exam Flashcards by Manar Almola

Question 1: What is the main reservoir for Shigella?
a) Soil
b) Humans and higher primates
c) Water
d) Livestock

b) Humans and higher primates

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Question 2: Which of the following virulence factors allows Salmonella typhimurium to compete with normal gut microflora?
a) Shiga toxin
b) Type III secretion system
c) Tetrathionate and ethanolamine utilization
d) Lipopolysaccharide

c) Tetrathionate and ethanolamine utilization

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Question 3: How does Vibrio cholerae’s quorum sensing affect its virulence?
a) It enhances virulence gene expression at high cell density.
b) It turns off virulence genes at high cell density.
c) It increases toxin production at low cell density.
d) It promotes biofilm formation regardless of cell density.

b) It turns off virulence genes at high cell density.

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Question 4: What role does urease play in Helicobacter pylori infections?
a) It facilitates biofilm formation.
b) It neutralizes gastric acid to promote survival.
c) It directly damages epithelial cells.
d) It inhibits the immune response.

b) It neutralizes gastric acid to promote survival.

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Question 5: Which virulence factor of Pseudomonas aeruginosa is primarily associated with chronic infections?
a) Type III secretion system
b) Pyocyanin production
c) Biofilm formation with alginate
d) Elastase secretion

c) Biofilm formation with alginate

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Question 6: What distinguishes primary syphilis from other stages of the disease?
a) Rash and systemic symptoms
b) Chancre at the site of infection
c) Severe arthritis
d) Heart failure

b) Chancre at the site of infection

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Question 7: Which fungal infection is commonly associated with bird and bat droppings?
a) Aspergillosis
b) Blastomycosis
c) Histoplasmosis
d) Candidiasis

c) Histoplasmosis

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Question 8: Which bioterrorism agent is categorized as a Category A agent due to its high public health impact?
a) Coxiella burnetti
b) Variola major
c) Burkholderia mallei
d) Yellow fever virus

b) Variola major

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Question 9: Which of the following bacteria causes foodborne gastroenteritis and is associated with poultry as a major reservoir?
a) Vibrio vulnificus
b) Campylobacter jejuni
c) Yersinia enterocolitica
d) Klebsiella pneumoniae

b) Campylobacter jejuni

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Question 10: What is the primary virulence factor of Shigella that allows it to inhibit host protein synthesis?
a) Lipopolysaccharide (LPS)
b) Shiga toxin
c) Type III secretion system
d) Exotoxin A

b) Shiga toxin

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Question 11: What characteristic of Pseudomonas aeruginosa contributes to its inherent antibiotic resistance?
a) Production of beta-lactamase only
b) Efflux pumps and outer membrane impermeability
c) Inactivation of antibiotics in the host
d) Use of quorum sensing to degrade antibiotics

b) Efflux pumps and outer membrane impermeability

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Question 12: Which symptom is most characteristic of bubonic plague?
a) Rice water stool
b) Bull’s eye rash
c) Swollen lymph nodes (buboes)
d) Severe arthritis

c) Swollen lymph nodes (buboes)

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Question 13: Why is penicillin ineffective against Chlamydia?
a) It lacks a cell membrane.
b) It lacks a significant peptidoglycan layer.
c) It produces beta-lactamases.
d) It is a facultative anaerobe.

b) It lacks a significant peptidoglycan layer.

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Question 14: What is the incubation period for pneumonic plague caused by Yersinia pestis?
a) 2-6 days
b) 1 day
c) 7-14 days
d) 12-24 hours

b) 1 day

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Question 15: What is the primary ecological environment of Vibrio cholerae?
a) Soil
b) Freshwater rivers
c) Brackish water environments
d) Human gastrointestinal tract

c) Brackish water environments

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Question 16: Which diagnostic test is used to confirm Helicobacter pylori infection by detecting urease activity?
a) Blood test
b) Endoscopy
c) Breath test
d) PCR test

c) Breath test

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Question 17: What is the primary mode of transmission for Lyme disease caused by Borrelia burgdorferi?
a) Airborne droplets
b) Vector-borne (tick bite)
c) Fecal-oral route
d) Direct contact with infected skin

b) Vector-borne (tick bite)

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Question 18: Which fungus is associated with infections in immunocompromised patients and can form biofilms on medical devices?
a) Blastomyces dermatitidis
b) Candida albicans
c) Coccidioides immitis
d) Aspergillus fumigatus

b) Candida albicans

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Question 19: What is a key feature of Neisseria meningitidis that contributes to its pathogenicity?
a) Production of Shiga toxin
b) Formation of biofilms on gallstones
c) Antiphagocytic polysaccharide capsule
d) Use of quorum sensing

c) Antiphagocytic polysaccharide capsule

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Question 20: Which of the following diseases is caused by Treponema pallidum?
a) Gonorrhea
b) Syphilis
c) Leptospirosis
d) Cholera

b) Syphilis

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Question 21: Which symptom is most characteristic of secondary syphilis?
a) Chancre at the infection site
b) Rash and lymphadenopathy
c) Gummas and blindness
d) Swollen, painful lymph nodes

b) Rash and lymphadenopathy

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Question 22: What is the main component of biofilms produced by Pseudomonas aeruginosa in cystic fibrosis patients?
a) Pyocyanin
b) Elastase
c) Alginate
d) Peptidoglycan

c) Alginate

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Question 23: Which enteric bacteria is primarily associated with biofilm formation on gallstones?
a) Escherichia coli
b) Klebsiella pneumoniae
c) Salmonella typhi
d) Shigella dysenteriae

c) Salmonella typhi

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Question 24: Which bacterial species is known to cause foodborne gastroenteritis from undercooked pork?
a) Yersinia enterocolitica
b) Vibrio parahaemolyticus
c) Salmonella typhimurium
d) Campylobacter jejuni

a) Yersinia enterocolitica

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Question 25: Which characteristic of Vibrio vulnificus is associated with its pathogenicity? a) Hemolysin production b) Capsule formation c) Quorum sensing d) Shiga toxin

b) Capsule formation

Question 26: What is the hallmark symptom of Lyme disease during its early phase? a) Severe arthritis b) Neurological symptoms c) Bull’s eye rash d) Fever and chills

c) Bull’s eye rash

Question 27: What is the primary treatment for cholera? a) Antibiotics like doxycycline b) Vaccination c) Rehydration therapy d) Antitoxin administration

c) Rehydration therapy

Question 29: Which fungal infection is commonly referred to as "Valley Fever"? a) Blastomycosis b) Histoplasmosis c) Coccidioidomycosis d) Aspergillosis

c) Coccidioidomycosis

Question 30: Which bioterrorism category includes agents like Ebola and Bacillus anthracis? a) Category A b) Category B c) Category C d) Category D

a) Category A

Question 31: What is the major toxin produced by Vibrio cholerae? a) Shiga toxin b) Cholera toxin (ctxA, ctxB genes) c) Exotoxin A d) Kanagawa hemolysin

b) Cholera toxin (ctxA, ctxB genes)

Question 32: Which pathogen is associated with Guillain-Barré Syndrome as a potential post-infectious complication? a) Campylobacter jejuni b) Helicobacter pylori c) Vibrio cholerae d) Yersinia pestis

a) Campylobacter jejuni

Question 33: What is the primary method of diagnosing Neisseria meningitidis infections? a) Gram stain of sputum b) Culture on chocolate agar c) PCR of blood samples d) Urease test

b) Culture on chocolate agar

Question 34: What is the primary function of the Type III Secretion System in Salmonella? a) Neutralizes gastric acid b) Promotes protein synthesis in host cells c) Injects effector proteins to rearrange host actin d) Stimulates quorum sensing

c) Injects effector proteins to rearrange host actin

Question 35: What is a distinguishing feature of spirochetes like Treponema pallidum? a) Gram-positive thick cell wall b) Obligate intracellular growth c) Helical shape and motility d) Production of exotoxins

c) Helical shape and motility

Question 36: What is the infectious form of Chlamydia during its growth cycle? a) Reticulate body b) Elementary body c) Spore form d) Trophozoite

b) Elementary body

Question 37: Which bacterial pathogen is a common cause of hot tub folliculitis? a) Vibrio parahaemolyticus b) Escherichia coli c) Pseudomonas aeruginosa d) Klebsiella pneumoniae

c) Pseudomonas aeruginosa

Question 38: What is the primary mechanism by which Shiga toxin inhibits protein synthesis? a) Binding to 30S ribosomal subunit b) Cleaving 28S rRNA of the ribosome and inhibit protein synthesis c) Inhibiting elongation factors d) Blocking RNA polymerase

b) Cleaving 28S rRNA of the ribosome and inhibit protein synthesis

Question 39: Which pathogen is responsible for rice-water stool diarrhea? a) Campylobacter jejuni b) Vibrio cholerae c) Salmonella typhi d) Shigella dysenteriae

b) Vibrio cholerae

Question 40: What is the primary mode of transmission for Neisseria gonorrhoeae? a) Fecal-oral route b) Sexual contact c) Inhalation of aerosols d) Contaminated water

b) Sexual contact

Question 41: Which stage of syphilis is characterized by gummas? a) Primary b) Secondary c) Tertiary d) Congenital

c) Tertiary

Question 42: What virulence factor allows Klebsiella pneumoniae to evade phagocytosis? a) Capsule b) Lipopolysaccharide c) Fimbriae d) Exotoxin

a) Capsule

Question 43: What is a common diagnostic feature of Coccidioides immitis infection? a) Detection of Shiga toxin b) Formation of spherules in tissue samples c) Presence of biofilm in the lungs d) Bull’s eye rash at the infection site

b) Formation of spherules in tissue samples

Question 44: What is a primary symptom of leptospirosis caused by Leptospira interrogans? a) Conjunctival suffusion b) Bloody diarrhea c) Petechial rash d) Pneumonia

a) Conjunctival suffusion

Question 45: Which pathogen uses BabA and SabA adhesins for colonization of the stomach? a) Campylobacter jejuni b) Vibrio cholerae c) Helicobacter pylori d) Salmonella typhi

c) Helicobacter pylori

Question 46: What virulence mechanism is unique to Vibrio parahaemolyticus? a) Type III secretion system b) Kanagawa hemolysin production c) Urease activity d) Endotoxin release

b) Kanagawa hemolysin production

Question 47: Which enteric pathogen is most infectious, requiring the lowest infectious dose (ID50)? a) Salmonella typhi b) Escherichia coli (EHEC) c) Shigella species d) Campylobacter jejuni

c) Shigella species

Question 48: What symptom differentiates pneumonic plague from bubonic plague? a) High fever b) Bloody sputum and shortness of breath c) Swollen lymph nodes (buboes) d) Rash and neurological symptoms

b) Bloody sputum and shortness of breath

Question 49: What is the primary vector for Borrelia burgdorferi, the causative agent of Lyme disease? a) Mosquito b) Flea c) Tick d) Louse

c) Tick

Question 50: Which fungal pathogen forms a fungus ball (aspergilloma) in the lungs? a) Blastomyces dermatitidis b) Aspergillus fumigatus c) Candida albicans d) Coccidioides immitis

b) Aspergillus fumigatus

Question 51: What is the typical reservoir for Yersinia pestis, the causative agent of plague? a) Birds b) Rodents c) Humans d) Water sources

b) Rodents

Question 52: Which virulence factor of Neisseria gonorrhoeae prevents phagolysosome fusion in host cells? a) Pili b) Porin protein (Por) c) Lipooligosaccharide (LOS) d) Opa protein

b) Porin protein (Por)

Question 53: Which organism is known for its spiral shape and hooked ends, causing leptospirosis? a) Treponema pallidum b) Borrelia burgdorferi c) Leptospira interrogans d) Vibrio vulnificus

c) Leptospira interrogans

Question 54: What is a major complication of untreated pelvic inflammatory disease (PID) caused by Neisseria gonorrhoeae? a) Guillain-Barré syndrome b) Infertility c) Septicemia d) Toxic shock syndrome

b) Infertility

Question 55: What is the main symptom of infections caused by Vibrio vulnificus? a) Severe diarrhea with rice-water stools b) Necrotizing wound infections c) Swollen lymph nodes d) Chronic cough

b) wound infections

Question 56: Which factor enables Helicobacter pylori to survive the acidic environment of the stomach? a) Capsule formation b) Quorum sensing c) Urease enzyme production d) Type III secretion system

c) Urease enzyme production

Question 57: What is the typical causative agent of athlete’s foot, a common dermatophyte infection? a) Candida albicans b) Trichophyton species c) Blastomyces dermatitidis d) Aspergillus fumigatus

b) Trichophyton species

Question 58: What component of lipopolysaccharide (LPS) in Gram-negative bacteria triggers a strong immune response? a) Lipid A b) Core polysaccharide c) O-antigen d) Peptidoglycan

a) Lipid A

Question 59: Which pathogen commonly causes UTIs and produces a characteristic blue-green pigment? a) Escherichia coli b) Klebsiella pneumoniae c) Pseudomonas aeruginosa d) Enterobacter cloacae

c) Pseudomonas aeruginosa

Question 60: Which form of plague is the most severe and can spread directly from person to person via respiratory droplets? a) Bubonic plague b) Septicemic plague c) Pneumonic plague d) Enteric plague

c) Pneumonic plague

Question 61: What is the typical presentation of cholera infection? a) Bloody diarrhea with pus b) Watery diarrhea resembling rice water c) Fever with rash d) Vomiting and severe abdominal pain

b) Watery diarrhea resembling rice water

Question 62: Which characteristic of Candida albicans contributes to its ability to form biofilms on medical devices? a) Dimorphism b) Production of hemolysins c) Capsule formation d) Endospore production

a) Dimorphism

Question 63: What zoonotic bacterium is associated with gastroenteritis and can be transmitted through unpasteurized milk or undercooked meat? a) Campylobacter jejuni b) Yersinia enterocolitica c) Salmonella typhimurium d) Vibrio parahaemolyticus

a) Campylobacter jejuni

Question 64: What is the defining laboratory characteristic of Neisseria meningitidis? a) Acid production from maltose and glucose b) Pigment production on chocolate agar c) Growth at 42°C d) Urease activity

a) Acid production from maltose and glucose

Question 65: Which pathogen produces pyocyanin, a blue-green pigment? a) Pseudomonas aeruginosa b) Vibrio cholerae c) Escherichia coli d) Shigella dysenteriae

a) Pseudomonas aeruginosa

Question 66: What specific molecular target does the A subunit of Shiga toxin affect, leading to inhibition of protein synthesis? a) The ribosomal 16S rRNA b) The ribosomal 28S rRNA c) Elongation factor EF-G d) The ribosomal 23S rRNA

b) The ribosomal 28S rRNA

Question 67: Which specific metabolic byproducts produced during inflammation enhance the competitive advantage of Salmonella typhimurium in the gut? a) Tetrathionate and ethanolamine b) Acetate and propionate c) Butyrate and lactate d) Sulfate and hydrogen sulfide

a) Tetrathionate and ethanolamine

Question 70: What specific adhesin of Helicobacter pylori is associated with binding to sialylated glycans on gastric epithelial cells? a) BabA b) SabA c) Urease d) CagA

B. SabA

Question 81: What type of secretion system does Shigella use to inject effectors into host cells? a) Type I b) Type II c) Type III d) Type IV

c) Type III

Question 82: Which bacterial species forms biofilms on gallstones, contributing to its persistence as a chronic reservoir? a) Klebsiella pneumoniae b) Salmonella typhi c) Vibrio cholerae d) Helicobacter pylori

b) Salmonella typhi

Question 83: How does Salmonella typhimurium compete with the gut microbiota during an inflammatory response? a) By producing a Type II secretion system b) By utilizing tetrathionate and ethanolamine c) By producing Shiga toxin d) By forming biofilms in the intestinal lumen

b) By utilizing tetrathionate and ethanolamine

Question 85: What characteristic distinguishes pneumonic plague from other forms of plague? a) It is zoonotic and transmitted by fleas. b) It spreads through direct droplet nuclei between humans. c) It requires a high infectious dose. d) It causes swollen lymph nodes (buboes).

b) It spreads through direct droplet nuclei between humans.

Question 86: What virulence factor allows Vibrio cholerae to adhere to epithelial cells? a) Cholera toxin (CtxA and CtxB) b) Quorum sensing molecules c) Toxin co-regulated pilus (TCP) d) Kanagawa hemolysin

c) Toxin co-regulated pilus (TCP)

Question 87: Which virulence factor of Helicobacter pylori is directly associated with gastric carcinoma? a) BabA adhesin b) Urease enzyme c) CagA protein d) VacA toxin

c) CagA protein

Question 88: What is the role of quorum sensing in Pseudomonas aeruginosa infections? a) Suppresses immune recognition of biofilms b) Coordinates the production of virulence factors like elastase and pyocyanin c) Directs adhesion to epithelial cells d) Triggers apoptosis in host macrophages

b) Coordinates the production of virulence factors like elastase and pyocyanin

Question 89: What type of bacteria are Treponema pallidum, Borrelia burgdorferi, and Leptospira interrogans? a) Gram-positive cocci b) Gram-negative rods c) Spirochetes d) Facultative anaerobes

c) Spirochetes

Question 90: Which specific diagnostic technique is commonly used for identifying Treponema pallidum in suspected syphilis cases? a) Urease breath test b) Darkfield microscopy c) Culture on selective media d) Acid-fast staining

b) Darkfield microscopy

Question 92: Which pathogen is associated with rice-water stool diarrhea and is found in brackish water environments? a) Salmonella typhi b) Vibrio cholerae c) Campylobacter jejuni d) Shigella dysenteriae

b) Vibrio cholerae

Question 93: What is the primary mechanism by which Pseudomonas aeruginosa resists antibiotics in biofilms? a) Overproduction of beta-lactamases b) Impaired penetration due to alginate matrix c) Active efflux of antibiotics d) Quorum sensing suppression

b) Impaired penetration due to alginate matrix

Question 96: Which virulence factor of Neisseria meningitidis is primarily responsible for its hyperproduction of endotoxins, leading to severe inflammation? a) Lipooligosaccharide (LOS) b) Type IV pili c) IgA protease d) Porin protein (Por)

a) Lipooligosaccharide (LOS)

Question 97: What laboratory medium is used for culturing Hemophilus influenzae, which requires both X (hemin) and V (NAD) factors for growth? a) MacConkey agar b) Chocolate agar c) Blood agar d) Eosin-methylene blue agar

b) Chocolate agar

Question 98: What symptom differentiates Coccidioidomycosis (Valley Fever) from other fungal infections? a) Bull’s eye rash b) Spherules in infected tissue c) Necrotizing fasciitis d) Chronic cough with thick sputum

b) Spherules in infected tissue

Question 99: What condition is commonly associated with Aggregatibacter actinomycetemcomitans (AA) in oral infections? a) Dental caries b) Aggressive periodontitis c) Chronic gingivitis d) Fungal biofilm formation

b) Aggressive periodontitis

Question 2: What is the major virulence mechanism of Shigella? a) Capsule formation b) Shiga toxin c) Quorum sensing d) Biofilm formation

b) Shiga toxin

Question 6: What is a hallmark sign of Shigella infection? a) Profuse watery diarrhea without blood b) Lower abdominal cramps, tenesmus, and blood in stool c) High fever and constipation d) Rash and joint pain

b) Lower abdominal cramps, tenesmus, and blood in stool

Question 7: Which Salmonella subspecies is primarily associated with cold-blooded animals? a) S. enterica var typhi b) S. typhimurium c) S. bongori d) S. enterica var enteritidis

c) S. bongori

Question 8: How does Salmonella typhimurium compete with normal gut flora during inflammation? a) By producing biofilms in the intestinal lumen b) By utilizing tetrathionate and ethanolamine c) By secreting Shiga toxin d) By inducing apoptosis in neighboring cells

b) By utilizing tetrathionate and ethanolamine

Question 9: What is the role of biofilm formation in S. typhi infections? a) Biofilms protect the bacteria in the intestinal lumen. b) Biofilms in the gallbladder contribute to chronic infection. c) Biofilms help S. typhi adhere to epithelial cells. d) Biofilms enhance antibiotic resistance in macrophages

Correct Answer: b) Biofilms in the gallbladder contribute to chronic infection.

Question 10: How does Salmonella inhibit the activation of T cells? a) By producing biofilms in lymphatic tissues b) By interfering with the MHC-II pathway in dendritic cells c) By cleaving host cytokines d) By inducing apoptosis in T cells directly

Correct Answer: b) By interfering with the MHC-II pathway in dendritic cells

Question 11: Which component of Salmonella's Type III secretion system is responsible for actin rearrangement in host cells? a) Effector proteins b) Lipopolysaccharide (LPS) c) Capsule polysaccharides d) Biofilm matrix proteins

Correct Answer: a) Effector proteins

Question 12: What clinical condition is associated with Klebsiella pneumoniae? a) Enteric fever b) Primary and secondary pneumonia c) Watery diarrhea d) Rash and joint pain

b) Primary and secondary pneumonia

Question 13: Which virulence factor contributes to the persistence of S. typhimurium during an inflammatory response? a) Lipopolysaccharide (LPS) b) Tetrathionate and ethanolamine utilization c) Shiga toxin production d) IgA protease activity

a) Lipopolysaccharide (LPS) b) Tetrathionate and

Question 14: Which enteric pathogen has the highest infectious dose (ID50) among those listed? a) Shigella b) EHEC c) S. typhi d) S. typhimurium

c) S. typhi

Question 15: What is a common feature of both Shigella and EHEC toxins? a) Both are endotoxins. b) Both target Gb3 receptors on host cells. c) Both cause host immune suppression. d) Both are encoded by plasmids.

b) Both target Gb3 receptors on host cells.

Question 2: What is the incubation period for bubonic plague? a) 1 day b) 2–6 days c) 7–10 days d) 12–24 hours

b) 2–6 days

Question 4: What virulence factor of Yersinia pestis allows it to evade phagocytosis? a) Kanagawa hemolysin b) Antiphagocytic protein capsule (F1 gene) c) Cholera toxin d) Flagellum

b) Antiphagocytic protein capsule (F1 gene)

Question 5: How does the plasminogen activator (pla) protease gene of Yersinia pestis contribute to virulence? a) It inhibits cytokine production. b) It disrupts actin filaments in host cells. c) It degrades fibrin clots and complement components. d) It stimulates cAMP production in host cells.

c) It degrades fibrin clots and complement components.

Question 6: What is the primary treatment for Yersinia pestis infections? a) Penicillin and rehydration therapy b) Streptomycin or gentamicin c) Doxycycline and azithromycin d) Ciprofloxacin and antifungal therapy

b) Streptomycin or gentamicin

Question 7: Which non-plague Yersinia species is associated with foodborne infections from undercooked pork? a) Yersinia pestis b) Yersinia pseudotuberculosis c) Yersinia enterocolitica d) Vibrio vulnificus

c) Yersinia enterocolitica

Question 8: What is the ecological environment of Vibrio cholerae? a) Freshwater lakes and rivers b) Brackish water environments c) Soil contaminated with animal feces d) Marine ecosystems with high salinity

b) Brackish water environments

Question 9: What is the primary mechanism by which cholera toxin causes diarrhea? a) Inhibits phagocytosis b) Stimulates cAMP production in intestinal cells c) Induces apoptosis in macrophages d) Degrades fibrin clots in the gut

b) Stimulates cAMP production in intestinal cells

Question 10: How does quorum sensing in Vibrio cholerae affect its virulence? a) High cell density increases toxin production. b) High cell density inhibits virulence genes and promotes detachment from the host. c) Low cell density suppresses biofilm formation. d) Low cell density enhances adhesion to epithelial cells.

b) High cell density inhibits virulence genes and promotes detachment from the host.

Question 11: What specific virulence factor of Vibrio parahaemolyticus lyses human blood cells? a) Kanagawa hemolysin b) Capsule formation c) Cholera toxin d) Toxin co-regulated pilus

a) Kanagawa hemolysin

Question 12: Which non-cholera Vibrio species is commonly associated with necrotizing wound infections and raw oyster consumption? a) Vibrio cholerae b) Vibrio vulnificus c) Vibrio parahaemolyticus d) Yersinia pseudotuberculosis

b) Vibrio vulnificus

Question 13: What is a unique characteristic of Vibrio cholerae biofilm growth? a) It requires tetrathionate for nutrient acquisition. b) It is stimulated by attachment to chitin. c) It inhibits quorum sensing under high cell density. d) It forms only in freshwater environments.

b) It is stimulated by attachment to chitin.

Question 14: Which type of plague is characterized by bleeding in the extremities and sudden fever? a) Bubonic plague b) Septicemic plague c) Pneumonic plague d) Enzootic plague

b) Septicemic plague

Question 15: Which Vibrio species is associated with gastroenteritis from consuming contaminated seafood (raw oysters)? a) Vibrio cholerae O1 b) Vibrio vulnificus c) Vibrio parahaemolyticus d) Yersinia enterocolitica

c) Vibrio parahaemolyticus

Question 1: What unique characteristic of Pseudomonas aeruginosa contributes to its identification in clinical settings? a) Growth at 42°C b) Production of a grape-like or tortilla-like odor c) Hemolysis on blood agar d) Presence of sulfur granules

b) Production of a grape-like or tortilla-like odor

Question 2: Which virulence factor of P. aeruginosa is controlled by quorum sensing and generates reactive oxygen species? a) Pyocyanin b) Elastase c) Alginate d) Peptidoglycan fragments

a) Pyocyanin

Question 3: How does Pseudomonas aeruginosa biofilm formation affect its antibiotic resistance? a) Biofilms prevent quorum sensing. b) Biofilm matrix reduces antibiotic penetration. c) Biofilms increase production of exotoxins. d) Biofilms attract other pathogens for synergy.

b) Biofilm matrix reduces antibiotic penetration.

Question 4: Which condition is NOT commonly caused by Pseudomonas aeruginosa? a) Cystic fibrosis lung infections b) Hot tub rash c) Endocarditis d) Diabetic food infections

c) Endocarditis

Question 5: What allows P. aeruginosa to thrive in cystic fibrosis lungs? a) Toxin-mediated damage to alveoli b) Formation of alginate-based biofilms c) Production of kanagawa hemolysin d) Use of host DNA for replication

b) Formation of alginate-based biofilms

Question 6: What is the function of the three quorum sensing systems in Pseudomonas aeruginosa? a) Inhibit immune response b) Coordinate virulence factor production and biofilm formation c) Increase antibiotic resistance by efflux pumps d) Target peptidoglycan in competing bacteria

b) Coordinate virulence factor production and biofilm formation

Question 7: What type of infections are polymicrobial communities involving P. aeruginosa particularly associated with? a) Biofilm-associated infections b) Vector-borne diseases c) Foodborne illnesses d) Opportunistic fungal infections

a) Biofilm-associated infections

Question 8: Which stage of syphilis is characterized by the appearance of a chancre? a) Primary syphilis b) Secondary syphilis c) Tertiary syphilis d) Congenital syphilis

a) Primary syphilis

Question 9: Which diagnostic technique is most commonly used for detecting Treponema pallidum? a) Gram staining b) Darkfield microscopy c) Culture on selective media d) Immunohistochemistry

b) Darkfield microscopy

Question 10: What metal does Borrelia burgdorferi rely on for metabolic processes, unlike most bacteria? a) Iron (Fe) b) Zinc (Zn) c) Manganese (Mn) d) Copper (Cu)

c) Manganese (Mn)

Question 11: Which zoonotic spirochete is associated with hooked ends and causes leptospirosis? a) Treponema pallidum b) Borrelia burgdorferi c) Leptospira interrogans d) Vibrio vulnificus

c) Leptospira interrogans

Question 12: What is a hallmark symptom of the early phase of Lyme disease caused by Borrelia burgdorferi? a) Neurological dysfunction b) Severe arthritis c) Bull’s eye rash d) Septicemia

c) Bull’s eye rash

Question 13: Which phase of Lyme disease is characterized by arthritis-like symptoms? a) Early localized phase b) Early disseminated phase c) Late persistent phase d) Congenital phase

c) Late persistent phase

Question 15: What is the primary treatment for syphilis? a) Streptomycin b) Gentamicin c) Penicillin d) Tetracycline

c) Penicillin

Question 1: What is the primary reservoir for Neisseria gonorrhoeae? a) Humans b) Rodents c) Soil d) Water

a) Humans

Question 2: What clinical symptom is most characteristic of gonorrhea in men? a) Pelvic inflammatory disease (PID) b) Dysuria and purulent discharge c) Petechiae and joint pain d) Chronic cough

b) Dysuria and purulent discharge

Question 3: Which virulence factor of N. gonorrhoeae prevents phagolysosome fusion in host cells? a) Opa protein b) Porin protein (Por) c) Pili d) Lipooligosaccharide (LOS)

b) Porin protein (Por)

Question 4: What is the consequence of untreated pelvic inflammatory disease (PID) in women caused by N. gonorrhoeae? a) Formation of granulomas b) Infertility due to fallopian tube scarring c) Urethritis and dysuria d) Chronic disseminated gonococcal infection

b) Infertility due to fallopian tube scarring

Question 5: Which diagnostic medium is used to grow N. gonorrhoeae in the laboratory? a) MacConkey agar b) Chocolate agar with CO₂ enrichment c) Blood agar d) Eosin-methylene blue (EMB) agar

b) Chocolate agar with CO₂ enrichment

Question 6: What treatment is used to prevent ophthalmia neonatorum in newborns caused by N. gonorrhoeae? a) Oral amoxicillin b) Intravenous penicillin c) 1% tetracycline or 0.5% erythromycin eye ointment d) Ciprofloxacin eye drops

c) 1% tetracycline or 0.5% erythromycin eye ointment

Question 7: What is a key virulence factor of Neisseria meningitidis that allows it to evade phagocytosis? a) Pili-mediated adherence b) Polysaccharide capsule c) Lipooligosaccharide (LOS) endotoxin d) IgA protease

b) Polysaccharide capsule

Question 8: How does N. meningitidis cause damage to host tissues? a) Through the production of Shiga toxin b) By hyperproduction of membrane vesicles and LOS endotoxin c) By inhibiting cytokine production in macrophages d) Through biofilm formation in the bloodstream

b) By hyperproduction of membrane vesicles and LOS endotoxin

Question 9: Which sugars does N. meningitidis ferment for acid production in laboratory tests? a) Glucose and lactose b) Glucose and maltose c) Maltose and sucrose d) Sucrose and lactose

b) Glucose and maltose

Question 10: What is the composition of the vaccine used for N. meningitidis prevention? a) Inactivated whole-cell bacteria b) Polysaccharide components from serogroups A, C, Y, W135 c) Recombinant Opa protein d) Live-attenuated N. meningitidis

b) Polysaccharide components from serogroups A, C, Y, W135

Question 11: What are the growth requirements for Hemophilus influenzae? a) Iron and calcium ions b) X factor (hemin) and V factor (NAD) c) Glucose and pyruvate d) Lactose and maltose

b) X factor (hemin) and V factor (NAD)

Question 12: Which medium is used to culture H. influenzae? a) MacConkey agar b) Chocolate agar c) Blood agar d) Thayer-Martin agar

b) Chocolate agar

Question 14: What characteristic of Hemophilus influenzae allows it to change its shape? a) Biofilm formation b) Pleomorphic morphology c) Production of endotoxins d) Capsule formation

b) Pleomorphic morphology

Question 1: What feature allows Helicobacter pylori to survive in the acidic environment of the stomach? a) Biofilm formation on the gastric epithelium b) Urease enzyme that buffers the acid by producing ammonia c) Capsule formation that protects from acidity d) Production of exotoxin that neutralizes stomach acid

b) Urease enzyme that buffers the acid by producing ammonia

Question 2: Which virulence factor of Helicobacter pylori is associated with gastric carcinoma? a) BabA b) SabA c) CagA d) VacA

c) CagA

Question 3: What was Barry Marshall's significant contribution to understanding Helicobacter pylori? a) Developed the breath test for urease detection b) Proved the link between Helicobacter pylori and gastric ulcers through self-inoculation c) Discovered the BabA and SabA adhesins d) Created a vaccine against Helicobacter pylori

b) Proved the link between Helicobacter pylori and gastric ulcers through self-inoculation

Question 6: What function does the BabA adhesin of H. pylori serve? a) Neutralizes gastric acid b) Binds to blood group antigens on epithelial cells c) Induces apoptosis in host cells d) Disrupts actin filaments in epithelial cells

b) Binds to blood group antigens on epithelial cells

Question 7: What is a key growth requirement for Campylobacter species? a) High oxygen concentration b) Low temperature (below 20°C) c) Microaerophilic conditions with 42°C incubation d) Anaerobic conditions and 37°C incubation

c) Microaerophilic conditions with 42°C incubation

Question 8: What immune disorder is associated with Campylobacter infection? a) Guillain-Barré Syndrome b) Rheumatoid arthritis c) Crohn's disease d) Systemic lupus erythematosus

a) Guillain-Barré Syndrome

Question 9: Why is Campylobacter difficult to grow in a laboratory? a) It requires high nutrient media and oxygen-free conditions. b) It is sensitive to oxygen and requires specialized low oxygen and high CO₂ conditions. c) It cannot be cultured outside of a host organism. d) It grows only in acidic environments.

b) It is sensitive to oxygen and requires specialized low oxygen and high CO₂ conditions.

Question 10: What is the primary reservoir for Campylobacter species? a) Human gastrointestinal tract b) Contaminated soil c) Poultry and other animals d) Freshwater environments

c) Poultry and other animals

Question 11: Why is penicillin ineffective against Chlamydia? a) Chlamydia is resistant to all beta-lactam antibiotics. b) Chlamydia lacks a significant peptidoglycan layer in its cell wall. c) Chlamydia produces enzymes that degrade penicillin. d) Chlamydia grows only inside host cells, preventing antibiotic action.

b) Chlamydia lacks a significant peptidoglycan layer in its cell wall.

Question 12: Which form of Chlamydia is infectious? a) Reticulate body (RB) b) Elementary body (EB) c) Sporulated body (SB) d) Vegetative body (VB)

b) Elementary body (EB)

Question 13: What is the metabolically active and non-infectious form of Chlamydia? a) Reticulate body (RB) b) Elementary body (EB) c) Sporulated body (SB) d) Vegetative body (VB)

a) Reticulate body (RB)

Question 14: Which antibiotic is commonly used to treat Chlamydia infections? a) Penicillin b) Azithromycin c) Vancomycin d) Ciprofloxacin

b) Azithromycin

Question 15: What is a severe outcome of untreated Chlamydia trachomatis infections? a) Blindness b) Sepsis c) Endocarditis d) Chronic diarrhea

a) Blindness

Question 1: What is the primary objective of bioterrorism? a) To promote scientific advancements in microbiology b) To produce death or disease in humans, animals, or plants for unlawful purposes c) To create vaccines for biological agents d) To establish environmental safety protocols

b) To produce death or disease in humans, animals, or plants for unlawful purposes

Question 3: Which category of bioterrorism agents includes pathogens with the highest risk to public and national security? a) Category A b) Category B c) Category C d) Category D

a) Category A

Question 4: Which of the following is an example of a Category A bioterrorism agent? a) Coxiella burnetii (Q fever) b) Bacillus anthracis (anthrax) c) Staphylococcus enterotoxin B d) Multidrug-resistant tuberculosis

b) Bacillus anthracis (anthrax)

Question 5: What is a defining characteristic of Category B bioterrorism agents? a) High mortality rates and major public panic b) Moderately easy to spread and cause moderate illness rates c) Emerging pathogens with potential for high morbidity and mortality d) Requires no special laboratory or monitoring capacity

b) Moderately easy to spread and cause moderate illness rates

Question 6: Which of the following is NOT a characteristic of an ideal bioweapon? a) Robust and stable under various environmental conditions b) Easy to detect and diagnose c) Contagious and virulent d) Resistant to drugs

b) Easy to detect and diagnose

Question 7: Which of the following is a possible delivery method for a bioterrorism agent? a) Contaminated mail b) Aerosolized via aircraft sprayers c) Introduced into food or water supplies d) All of the above

d) All of the above

Question 8: Which pathogen belongs to Category C bioterrorism agents? a) Yellow fever virus b) Yersinia pestis (plague) c) Francisella tularensis (tularemia) d) Burkholderia mallei (glanders)

a) Yellow fever virus

Question 9: What makes Category C bioterrorism agents particularly concerning? a) They have been eradicated globally. b) They are resistant to all forms of antibiotics. c) They are easily produced and have high potential for morbidity and mortality. d) They are undetectable in environmental samples.

c) They are easily produced and have high potential for morbidity and mortality.

Question 10: Which toxin is associated with Category B bioterrorism agents? a) Clostridium botulinum toxin b) Epsilon toxin of Clostridium perfringens c) Filoviruses (Ebola, Marburg) d) Multidrug-resistant tuberculosis

b) Epsilon toxin of Clostridium perfringens

Question 11: Why is detecting a bioterrorism incident challenging? a) Most bioweapons cannot infect humans. b) Symptoms often mimic common illnesses, making diagnosis difficult. c) Bioweapons only affect animals and plants. d) There are no laboratory methods to detect bioterrorism agents.

b) Symptoms often mimic common illnesses, making diagnosis difficult.

Question 12: What role do local public health departments play in responding to a bioterrorism event? a) Conducting military operations against perpetrators b) Assessing health impacts in the community and ensuring water safety c) Developing new vaccines within days of detection d) Enforcing quarantine laws globally

b) Assessing health impacts in the community and ensuring water safety

Question 13: How can clinical and epidemiological data help identify a bioterrorism event? a) By making standard diagnostic procedures obsolete b) By identifying unusual patterns of disease spread c) By eliminating the need for infection control protocols d) By proving that bioterrorism agents cannot affect humans

b) By identifying unusual patterns of disease spread

Question 14: What is a critical step for preparing the healthcare system to respond to a bioterrorism incident? a) Removing all standard infection control measures b) Familiarizing medical staff with bioterrorism agents and their symptoms c) Eliminating epidemiological data analysis protocols d) Training healthcare workers to ignore unverified reports of unusual illness

b) Familiarizing medical staff with bioterrorism agents and their symptoms

Question 1: What is the primary cause of gingivitis? a) Systemic infections b) Plaque accumulation on teeth c) Deficiency in vitamin D d) Chronic viral infections

b) Plaque accumulation on teeth

Question 2: What condition is associated with untreated gingivitis that progresses to bone destruction? a) Dental caries b) Periodontal disease c) Apical abscess d) Pericoronitis

b) Periodontal disease

Question 3: How can periodontal disease during pregnancy affect maternal health? a) It decreases the risk of gestational diabetes. b) It increases the risk of preterm births. c) It causes permanent tooth loss. d) It prevents gestational hypertension.

b) It increases the risk of preterm births.

Question 4: How does periodontal disease relate to diabetes? a) It improves glycemic control. b) It reduces the risk of developing diabetes. c) It likely contributes to diabetes development. d) It causes insulin overproduction.

c) It likely contributes to diabetes development.

Question 5: What role does Streptococcus mutans (S. mutans) play in tooth decay? a) Produces glucans and lactic acid, contributing to enamel erosion b) Invades dentinal tubules and induces immune suppression c) Produces toxins that destroy dental pulp d) Prevents the formation of bacterial biofilms

a) Produces glucans and lactic acid, contributing to enamel erosion

Question 6: Which bacterial species is primarily involved in producing acid from sugars during the tooth decay process? a) Aggregatibacter actinomycetemcomitans b) Lactobacilli c) Staphylococcus aureus d) Porphyromonas gingivalis

b) Lactobacilli

Question 7: Which of the following describes the progression of tooth decay? a) Plaque formation → dentin destruction → pulp infection b) Enamel erosion → periodontal disease → tooth fracture c) Biofilm formation → apical abscess → pulp necrosis d) Tartar accumulation → gum infection → bone loss

a) Plaque formation → dentin destruction → pulp infection

uestion 8: Which of the following is a type of periodontal disease? a) Necrotizing ulcerative gingivitis (NUG) b) Acute necrotizing ulcerative gingivitis (ANUG) c) Necrotizing ulcerative periodontitis (NUP) d) All of the above

d) All of the above

Question 9: What is an important feature of the oral cavity as a microbial ecosystem? a) It is dominated by viral pathogens only. b) Co-aggregation and biofilm formation are key for microbial colonization. c) It lacks polymicrobial interactions. d) Microbial populations are entirely anaerobic.

b) Co-aggregation and biofilm formation are key for microbial colonization.

Question 10: Which pathogen exhibits altered gene expression in the presence of S. gordonii? a) Aggregatibacter actinomycetemcomitans (AA) b) Streptococcus mutans c) Porphyromonas gingivalis d) Lactobacilli

a) Aggregatibacter actinomycetemcomitans (AA)

Question 11: Which of the following is NOT a method for preventing oral infections? a) Regular brushing and flossing b) Fluoride treatment c) Antibiotic prophylaxis for every individual d) Scaling and plaque removal Correct Answer: c) Antibiotic prophylaxis for every individual

c) Antibiotic prophylaxis for every individual

Where are fungi typically found in the environment? A) In animal tissues B) In soil and on plants C) Only in tropical climates D) Only in human bodies

B) In soil and on plants

What does it mean for a fungus to be 'dimorphic'? A) It only exists as yeast B) It can exist in both yeast and mold forms C) It produces spores only in the yeast form D) It does not reproduce sexually

B) It can exist in both yeast and mold forms

How do fungal spores differ from bacterial endospores? A) Fungal spores are more resistant to heat B) Fungal spores are not dormant and cannot survive harsh conditions C) Fungal spores are involved in asexual reproduction, while bacterial endospores are for survival D) Fungal spores are not produced in both forms of fungi

C) Fungal spores are involved in asexual reproduction, while bacterial endospores are for survival

What is the primary difference between a superficial and systemic fungal infection? A) Superficial infections affect the skin, while systemic infections affect internal organs B) Systemic infections are always caused by yeasts C) Superficial infections are less common than systemic ones D) Systemic infections do not require antifungal treatment

A) Superficial infections affect the skin, while systemic infections affect internal organs

What is the significance of the term 'mycoses'? A) It refers to the process of fungal reproduction B) It describes a group of fungal infections C) It is the name for the fungal cell wall D) It refers to fungal spores only

B) It describes a group of fungal infections

What is the most common portal of entry for Aspergillus species? A) Gastrointestinal tract B) Respiratory tract C) Skin contact D) Bloodstream

B) Respiratory tract

What is an Aspergilloma, and where does it form in the body? A) A type of yeast infection in the mouth B) A fungal ball in the lungs C) A skin infection caused by Aspergillus D) A systemic infection in the liver

B) A fungal ball in the lungs

Which antifungal treatment is considered more effective for Aspergillosis: voriconazole or amphotericin B? A) Voriconazole B) Amphotericin B C) Both are equally effective D) Neither

A) Voriconazole

What is the causative agent of blastomycosis, and where is it typically found? A) Aspergillus fumigatus; in the lungs B) Blastomyces dermatitidis; in soil in wooded areas C) Coccidioides immitis; in dry alkaline soils D) Candida albicans; on mucosal surfaces

B) Blastomyces dermatitidis; in soil in wooded areas

What forms does Blastomyces dermatitidis take during its lifecycle? A) Only as a mold B) Only as a yeast C) Mold and yeast (dimorphic) D) Bacteria and yeast

C) Mold and yeast (dimorphic)

How does blastomycosis typically spread in the body? A) Through the gastrointestinal tract B) From the lungs to other body parts C) By direct skin contact D) Through the bloodstream only

B) From the lungs to other body parts

What is the most common species responsible for candidiasis? A) Aspergillus fumigatus B) Candida albicans C) Blastomyces dermatitidis D) Coccidioides immitis

B) Candida albicans

Why are patients with medical devices at higher risk for candidiasis? A) Devices prevent fungal spores from being cleared B) Candida species can form biofilms on the devices C) Medical devices kill Candida species D) Biofilms prevent antifungal treatments from working

B) Candida species can form biofilms on the devices

How is Coccidioidomycosis transmitted to humans? A) By insect bites B) By inhaling spores from the soil C) By direct skin contact D) By contaminated water

B) By inhaling spores from the soil

Which fungus causes Pneumocystis pneumonia, and who is at risk for this infection? A) Histoplasma capsulatum; elderly B) Pneumocystis jirovecii; people with AIDS C) Candida albicans; newborns D) Aspergillus fumigatus; cancer patients

B) Pneumocystis jirovecii; people with AIDS

What diagnostic tools are used to confirm Pneumocystis pneumonia? A) Blood cultures and CT scan B) Chest X-ray and fluorescent antibody tests C) Skin biopsy and blood test D) Urine test and culture

B) Chest X-ray and fluorescent antibody tests

What are some examples of dermatophyte infections? A) Thrush and candidiasis B) Athlete’s foot, ringworm, jock itch C) Pneumonia and tuberculosis D) Skin lesions and oral thrush

B) Athlete’s foot, ringworm, jock itch

How are dermatophyte infections typically transmitted? A) Airborne spores B) Skin-to-skin contact or contaminated surfaces C) Blood contact D) Insect bites

B) Skin-to-skin contact or contaminated surfaces

What is the standard treatment for dermatophyte infections? A) Oral antifungals B) Topical fungicides (azoles) C) Steroid creams D) Antibiotics

B) Topical fungicides (azoles)

PFGE (Pulsed-Field Gel Electrophoresis) is primarily used for: a) Amplifying DNA sequences exponentially b) Comparing bacterial strains in epidemiological studies c) Identifying specific DNA/RNA sequences d) Producing fluorescent probes

b) Comparing bacterial strains in epidemiological studies

What is the main purpose of FISH (Fluorescent In Situ Hybridization)? a) Amplifying DNA sequences b) Diagnosing antibiotic resistance c) Identifying specific organisms or genes in complex samples d) Separating large DNA fragments

c) Identifying specific organisms or genes in complex samples

Which enzyme is critical for PCR? a) Urease b) Taq polymerase c) Lysozyme d) Mycolic acid

b) Taq polymerase

Sensitivity in diagnostic tests is defined as: a) The ability to correctly identify true negatives b) The ability to correctly identify true positives c) Detecting antimicrobial resistance d) Balancing false positives and false negatives

b) The ability to correctly identify true positives

MIC (Minimum Inhibitory Concentration) refers to: a) The lowest concentration of an antibiotic that kills 99.9% of bacteria b) The lowest concentration of an antibiotic that inhibits visible growth c) A method to measure DNA amplification d) A technique for immune cell activation

b) The lowest concentration of an antibiotic that inhibits visible growth

What is opsonization? a) Engulfment of pathogens by neutrophils b) Coating of pathogens to enhance phagocytosis c) Systemic inflammatory response causing organ failure d) Direct lysis of bacterial cell walls

b) Coating of pathogens to enhance phagocytosis

The vaccine against tuberculosis is called: a) Mantoux vaccine b) PPD vaccine c) BCG vaccine d) Latent TB prophylaxis

c) BCG vaccine

Which is a defining feature of Gram-positive bacteria? a) Outer membrane with endotoxins b) Thick peptidoglycan layer c) Acid-fast cell wall d) High motility

b) Thick peptidoglycan layer

EHEC infections are commonly associated with: a) Contaminated water b) Undercooked poultry c) Eating ground beef contaminated with cattle feces d) Antibiotic overuse

c) Eating ground beef contaminated with cattle feces

What differentiates LD50 from ID50? a) LD50 measures infectivity, while ID50 measures lethality. b) LD50 measures lethality, while ID50 measures infectivity. c) Both LD50 and ID50 measure toxin concentration. d) LD50 and ID50 are interchangeable

b) LD50 measures lethality, while ID50 measures infectivity.

Which of the following bacteria is a common cause of "walking pneumonia"? a) Klebsiella pneumoniae b) Streptococcus pneumoniae c) Mycoplasma pneumoniae d) Haemophilus influenzae

c) Mycoplasma pneumoniae

Which bacteria is known for its "swarming motility"? a) Escherichia coli b) Proteus mirabilis c) Bacillus anthracis d) Clostridioides difficile

b) Proteus mirabilis

What immune cell produces antibodies? a) T cells b) B cells c) Macrophages d) Neutrophils

b) B cells

What type of immunity is provided by maternal antibodies? a) Artificial active b) Artificial passive c) Natural active d) Natural passive

d) Natural passive

Which pathogen causes Lyme disease? a) Borrelia burgdorferi b) Yersinia pestis c) Vibrio cholerae d) Treponema pallidum

a) Borrelia burgdorferi

The primary toxin associated with cholera is: a) Shiga toxin b) Cholera toxin c) Alpha toxin d) Endotoxin

b) Cholera toxin

What is a characteristic feature of late-stage syphilis? a) Erythema migrans b) Rash on palms and soles c) Neurosyphilis and gummas d) Bull's-eye rash

c) Neurosyphilis and gummas

What is a primary treatment for septic shock? a) Opsonins b) Complement inhibitors c) Fluid resuscitation and vasopressors d) Mycolic acid

c) Fluid resuscitation and vasopressors

Which bacteria is associated with gastric ulcers? a) Campylobacter jejuni b) Vibrio cholerae c) Helicobacter pylori d) Shigella dysenteriae

c) Helicobacter pylori

hat is the shape and Gram status of Mycobacteria? a) Cocci, Gram-negative b) Rod-like, Gram-positive c) Cocci, Gram-positive d) Rod-like, Gram-negative

b) Rod-like, Gram-positive

hy are Mycobacteria classified as acid-fast? a) Presence of peptidoglycan b) Presence of mycolic acids in their cell wall c) Lack of a cell wall d) Resistance to basic dyes

b) Presence of mycolic acids in their cell wall

Which of the following is NOT true about Mycobacteria? a) They are aerobic. b) They form spores. c) They grow slowly. d) They are obligate human pathogens.

b) They form spores.

What is a key difference between latent TB and active TB? a) Latent TB is symptomatic; active TB is asymptomatic. b) Active TB is contagious; latent TB is not. c) Latent TB requires no treatment; active TB requires no treatment. d) Active TB shows a normal chest X-ray; latent TB shows an abnormal chest X-ray

b) Active TB is contagious; latent TB is not.

What test is commonly used to diagnose TB infection? a) Gram stain b) PPD skin test (Mantoux test) c) Acid-fast stain d) Wright’s stain

b) PPD skin test (Mantoux test)

What is the correct sequence of biofilm development? a) Early biofilm growth → dispersion → reversible attachment → irreversible attachment → maturation b) Dispersion → early biofilm growth → maturation → reversible attachment → irreversible attachment c) Reversible attachment → irreversible attachment → early biofilm growth → biofilm maturation → dispersion d) Irreversible attachment → reversible attachment → early biofilm growth → dispersion → biofilm maturation

c) Reversible attachment → irreversible attachment → early biofilm growth → biofilm maturation → dispersion

Biofilms are important in microbiology because: a) They are only found in laboratory conditions. b) They do not contribute to antibiotic resistance. c) They protect bacteria and increase resistance to antibiotics. d) They are a sign of poor bacterial survival strategies.

c) They protect bacteria and increase resistance to antibiotics.

Which type of E. coli is associated with travelers' diarrhea? a) Enterohemorrhagic E. coli (EHEC) b) Enteropathogenic E. coli (EPEC) c) Enteroinvasive E. coli (EIEC) d) Enterotoxigenic E. coli (ETEC)

d) Enterotoxigenic E. coli (ETEC)

Pediatric diarrhea caused by watery stools is most commonly associated with which E. coli? a) EHEC b) ETEC c) EPEC d) EIEC

c) EPEC

What toxin is characteristic of EHEC infections, such as O157:H7? a) Shiga-like toxin on a lysogenetic phage b) Cytolethal distending toxin c) Endotoxin d) Cytotoxic necrotizing factors

a) Shiga-like toxin on a lysogenetic phage

Eating undercooked ground beef contaminated with cattle feces is a risk factor for which E. coli infection? a) EPEC b) EHEC c) ETEC d) EIEC

b) EHEC

Watery diarrhea that may lead to dysentery is caused by: a) EPEC b) ETEC c) EHEC d) EIEC

d) EIEC

What structural component of Mycobacteria contributes to its slow growth rate and resistance to desiccation and chemical disinfectants? a) High lipid content in the outer membrane b) Thick peptidoglycan layer c) Mycolic acids in the cell wall d) Presence of porins

c) Mycolic acids in the cell wall

Which of the following is a potential outcome if latent TB is left untreated? a) Reactivation into active TB under immunocompromised conditions b) Complete resolution without any health impact c) Spontaneous elimination of TB bacteria d) Formation of granulomas leading to fibrosis and scarring

a) Reactivation into active TB under immunocompromised conditions

How do mycolic acids influence the staining properties of Mycobacteria during the acid-fast staining process? a) They form a hydrophobic layer that prevents dye penetration. b) They trap the primary stain, resisting decolorization with acid alcohol. c) They absorb the counterstain more effectively than the primary stain. d) They dissolve during the decolorization step

b) They trap the primary stain, resisting decolorization with acid alcohol.

What triggers the transition from reversible to irreversible attachment during biofilm formation? a) Depletion of nutrients in the surrounding environment b) Production of extracellular polymeric substances (EPS) c) Increase in population density d) Release of biofilm-dispersing factors

b) Production of extracellular polymeric substances (EPS)

In what clinical situations are biofilms particularly problematic? a) Respiratory tract infections caused by Mycobacteria b) Contaminated intravenous catheters and prosthetic devices c) Gastroenteritis caused by E. coli d) Acute infections treated with broad-spectrum antibiotics

b) Contaminated intravenous catheters and prosthetic devices

Which of the following mechanisms allows EHEC (O157:H7) to evade host defenses? a) Inhibition of macrophage activity by Shiga-like toxin b) Formation of actin pedestals to adhere tightly to intestinal epithelial cells c) Inhibition of complement system activation d) Secretion of enterotoxins that suppress immune response

b) Formation of actin pedestals to adhere tightly to intestinal epithelial cells

How does the enzyme urease contribute to the formation of kidney stones in Proteus mirabilis infections? a) By directly binding calcium ions to promote crystal formation b) By hydrolyzing urea into ammonia, which increases urine pH and leads to struvite precipitation c) By breaking down magnesium ions in the urinary tract d) By increasing the concentration of oxalates in urine

b) By hydrolyzing urea into ammonia, which increases urine pH and leads to struvite precipitation

Which of the following differentiates UPEC (uropathogenic E. coli) from Proteus mirabilis in UTIs? a) UPEC causes uncomplicated cystitis, while Proteus mirabilis is more commonly associated with catheter-associated UTIs. b) UPEC produces urease, while Proteus mirabilis does not. c) UPEC demonstrates swarming motility, while Proteus mirabilis does not. d) UPEC infections often result in kidney stones, while Proteus mirabilis infections rarely do.

a) UPEC causes uncomplicated cystitis, while Proteus mirabilis is more commonly associated with catheter-associated UTIs.

What feature of Proteus mirabilis is responsible for its characteristic swarming motility on agar plates? a) Flagellar arrangement b) Biofilm production c) Urease activity d) Spore formation

a) Flagellar arrangement

What is the primary toxin produced by Clostridium perfringens that leads to tissue necrosis and gas gangrene? a) Beta toxin b) Alpha toxin c) Tetanospasmin d) Botulinum toxin

b) Alpha toxin

Which feature is common to all pathogenic Clostridium species? a) Obligate aerobes b) Gram-positive, spore-forming, strict anaerobes c) Non-spore-forming rods d) Catalase-positive

b) Gram-positive, spore-forming, strict anaerobes

Match the clinical presentation with the appropriate Clostridium species: Tightening of the jaw and muscle spasms Gas bubbles and blackened skin in infected tissue Blurred vision and flaccid muscle paralysis Antibiotic-associated diarrhea and colitis a) C. difficile, C. tetani, C. perfringens, C. botulinum b) C. tetani, C. perfringens, C. botulinum, C. difficile c) C. perfringens, C. botulinum, C. tetani, C. difficile d) C. botulinum, C. difficile, C. perfringens, C. tetani

b) C. tetani, C. perfringens, C. botulinum, C. difficile

What is the function of the plasmids pXO1 and pXO2 in Bacillus anthracis? a) pXO1 codes for capsule formation, while pXO2 codes for toxin production. b) pXO1 codes for toxin production, while pXO2 codes for capsule formation. c) Both pXO1 and pXO2 code for spore formation. d) Both pXO1 and pXO2 code for antibiotic resistance.

b) pXO1 codes for toxin production, while pXO2 codes for capsule formation.

What differentiates cutaneous anthrax from pulmonary and gastrointestinal anthrax in terms of severity and presentation? a) Cutaneous anthrax is the most common and non-fatal, while pulmonary and gastrointestinal anthrax are rare but highly fatal. b) Cutaneous anthrax results in respiratory distress, while pulmonary and gastrointestinal anthrax result in skin lesions. c) Pulmonary anthrax is associated with black eschars, while cutaneous anthrax is not. d) Gastrointestinal anthrax is non-fatal and only affects the skin.

a) Cutaneous anthrax is the most common and non-fatal, while pulmonary and gastrointestinal anthrax are rare but highly fatal.

How does Clostridium difficile spread in healthcare settings? a) Airborne droplets b) Fecal-oral route c) Direct blood contact d) Sexual transmission

b) Fecal-oral route

What colony morphology is characteristic of Clostridium difficile when cultured on selective media? a) Smooth, convex colonies with a shiny appearance b) Flat, irregular, rough-edged colonies resembling a drumstick c) Swarming motility with a hazy growth pattern d) Mucoid colonies with a greenish tinge

b) Flat, irregular, rough-edged colonies resembling a drumstick

How does the increased pH caused by Proteus mirabilis directly affect urinary tract physiology? a) It increases immune cell activity in the urinary tract. b) It inhibits the growth of most bacterial pathogens. c) It promotes precipitation of magnesium ammonium phosphate crystals, leading to stone formation. d) It enhances the antibiotic susceptibility of the bacteria.

c) It promotes precipitation of magnesium ammonium phosphate crystals, leading to stone formation.

Which laboratory test would most effectively confirm urease activity in a suspected Proteus mirabilis UTI? a) Citrate utilization test b) Urease test c) Oxidase test d) Indole test

b) Urease test

In cases of gas gangrene caused by C. perfringens, what role does the alpha toxin play in pathogenesis? a) It activates immune cells to attack host tissues. b) It disrupts cell membranes, leading to cell death and tissue necrosis. c) It inhibits neutrophil migration to the site of infection. d) It induces apoptosis of endothelial cells.

b) It disrupts cell membranes, leading to cell death and tissue necrosis.

Which of the following methods is most effective for preventing the spread of Clostridium difficile in healthcare settings? a) Routine use of broad-spectrum antibiotics b) Frequent handwashing with soap and water c) Use of alcohol-based hand sanitizers d) Disinfecting surfaces with hydrogen peroxide alone

b) Frequent handwashing with soap and water

Which of the following bacterial pathogens is most likely to cause bloody diarrhea and is associated with contaminated ground beef? a) Escherichia coli (EHEC) b) Salmonella spp. c) Shigella spp. d) Clostridioides difficile

a) Escherichia coli (EHEC)

Which of the following is a characteristic feature of Shigella spp. infection? a) Watery diarrhea without blood b) Dysentery with mucus and blood in the stool c) Diarrhea with abdominal cramps and fever, but no blood d) Severe vomiting and watery diarrhea

b) Dysentery with mucus and blood in the stool

Which bacterium is primarily associated with antibiotic-associated diarrhea and the development of pseudomembranous colitis? a) Salmonella spp. b) Campylobacter jejuni c) Clostridioides difficile d) Mycoplasma pneumoniae

c) Clostridioides difficile

Which of the following is the most common bacterial cause of community-acquired pneumonia (CAP)? a) Mycoplasma pneumoniae b) Klebsiella pneumoniae c) Streptococcus pneumoniae d) Haemophilus influenzae

c) Streptococcus pneumoniae

Legionella pneumophila is most commonly transmitted through which of the following sources? a) Contaminated food b) Water systems, such as cooling towers and hot tubs c) Airborne particles from coughing d) Person-to-person transmission

b) Water systems, such as cooling towers and hot tubs

Klebsiella pneumoniae is most commonly associated with pneumonia in which of the following settings? a) Community-acquired infections in healthy individuals b) Nosocomial (hospital-acquired) infections, especially in immunocompromised patients c) Pneumonia in young, otherwise healthy children d) Viral pneumonia in elderly patients

b) Nosocomial (hospital-acquired) infections, especially in immunocompromised patients

Which bacterium is the most common cause of urinary tract infections and utilizes adhesins to attach to the urinary tract? a) Proteus mirabilis b) Escherichia coli (UPEC) c) Klebsiella pneumoniae d) Staphylococcus saprophyticus

b) Escherichia coli (UPEC)

Proteus mirabilis contributes to kidney stone formation due to which of the following mechanisms? a) Adhesin-mediated attachment to the urinary tract b) Urease production, raising the pH of urine c) Capsule formation preventing immune dete

b) Urease production, raising the pH of urine

During which stage of pertussis do the characteristic "whooping" sounds occur? a) Catarrhal stage b) Paroxysmal stage c) Convalescent stage d) Recovery stage

b) Paroxysmal stage

What is the primary mode of transmission for Bordetella pertussis? a) Contaminated food b) Airborne droplets c) Direct contact with infected individuals d) Waterborne routes

b) Airborne droplets

Which type of anthrax is associated with mediastinal widening on a chest X-ray? a) Cutaneous anthrax b) Inhalational anthrax c) Gastrointestinal anthrax d) Injectional anthrax

b) Inhalational anthrax

What are the three main virulence factors of Bacillus anthracis? a) Endotoxins, capsule, flagella b) Capsule, anthrax toxin, spores c) Capsule, edema factor, lethal factor d) Protective antigen, spores, biofilm formation

c) Capsule, edema factor, lethal factor

Which of the following is the primary function of the "B" subunit in AB toxins? a) Binding to host cell receptors b) Entering the host cell and disrupting pathways c) Altering protein synthesis in the host cell d) Damaging the cytoskeletal integrity

a) Binding to host cell receptors

What unique clinical feature differentiates gastrointestinal anthrax from other forms? a) Mediastinal widening b) Severe abdominal pain and vomiting c) Eschar formation on the skin d) Rapid progression to shock

b) Severe abdominal pain and vomiting

Which microorganism is commonly associated with infections in burn patients and individuals with cystic fibrosis? a) Candida albicans b) Pseudomonas aeruginosa c) Staphylococcus epidermidis d) Enterococcus faecalis

b) Pseudomonas aeruginosa

What is a key risk factor for developing opportunistic infections? a) Regular exercise b) Immunosuppression c) A high-protein diet d) Normal microbiota

b) Immunosuppression

Staphylococcus epidermidis infections are most commonly associated with which of the following? a) Use of broad-spectrum antibiotics b) Implanted medical devices c) Burn wounds d) Cystic fibrosis

b) Implanted medical devices

What mechanism allows Candida albicans to cause infection in individuals? a) High motility in the bloodstream b) Immune system evasion and biofilm formation c) Resistance to antifungal medications d) Adherence to ciliated epithelium

b) Immune system evasion and biofilm formation

What distinguishes opportunistic pathogens from true pathogens? a) Opportunistic pathogens always produce severe disease in healthy hosts. b) Opportunistic pathogens only cause disease in immunocompromised hosts or sterile body sites. c) True pathogens require immunosuppression to establish infection. d) True pathogens are unable to colonize healthy hosts.

b) Opportunistic pathogens only cause disease in immunocompromised hosts or sterile body sites.

Which pathogen is a leading cause of surgical site infections in healthcare settings? a) Pseudomonas aeruginosa b) Clostridioides difficile c) Staphylococcus aureus (including MRSA) d) Klebsiella pneumoniae

c) Staphylococcus aureus (including MRSA)

How is Pseudomonas aeruginosa typically transmitted in healthcare environments? a) Through airborne droplets b) Contaminated food c) Medical equipment like catheters or ventilators d) Direct contact with infected animals

c) Medical equipment like catheters or ventilators

What is the most effective method to prevent nosocomial infections? a) Avoiding hospital admissions b) Administering broad-spectrum antibiotics c) Hand hygiene, equipment sterilization, and infection control protocols d) Routine patient isolation

c) Hand hygiene, equipment sterilization, and infection control protocols

What does LD50 measure in terms of pathogen virulence? a) The number of microorganisms required to infect 50% of a test population b) The number of microorganisms or toxin dose required to kill 50% of a test population c) The rate of pathogen transmission in a population d) The time required for symptoms to appear after infection

b) The number of microorganisms or toxin dose required to kill 50% of a test population

Why is Shigella considered highly infectious? a) It produces a lethal toxin. b) It has an ID50 of 10-100 cells. c) It resists stomach acid better than Vibrio cholerae. d) It causes high mortality rates.

b) It has an ID50 of 10-100 cells.

Why does Vibrio cholerae have a higher ID50 compared to Shigella? a) It is less virulent. b) It requires more time to colonize the host. c) It is more susceptible to stomach acid. d) It only infects immunocompromised individuals.

c) It is more susceptible to stomach acid.

Which of the following is a characteristic of active immunity? a) Immediate onset of protection b) Short-lived protection lasting weeks to months c) Memory cells are produced d) Transfer of antibodies

c) Memory cells are produced

What is an example of passive immunity acquired naturally? a) Immunity after recovering from influenza b) Maternal antibodies transferred to the fetus c) Hepatitis B vaccine protection d) Rabies immunoglobulin post-exposure

b) Maternal antibodies transferred to the fetus

Why is passive immunity considered short-lived? a) It takes weeks to develop. b) Antibodies are not produced by the recipient’s immune system. c) It requires booster doses. d) It does not involve antigen exposure.

b) Antibodies are not produced by the recipient’s immune system.

Which of the following is an example of artificial active immunity? a) Polio vaccine b) Rabies immunoglobulin post-exposure c) Breastfeeding providing IgA antibodies d) Maternal IgG antibodies crossing the placenta

a) Polio vaccine

What is a key feature distinguishing active immunity from passive immunity? a) Active immunity involves antibody transfer. b) Passive immunity induces memory cells. c) Active immunity provides long-lasting protection. d) Passive immunity is slower to develop

c) Active immunity provides long-lasting protection.

What is the primary function of phagocytosis? a) Production of antibodies against pathogens b) Engulfing and destroying pathogens, dead cells, or debris c) Creating memory cells for future immune responses d) Neutralizing toxins released by pathogens

b) Engulfing and destroying pathogens, dead cells, or debris

What is the first step in the process of phagocytosis? a) Ingestion of the pathogen into a vesicle b) Binding of the phagocyte to the pathogen c) Chemotaxis, where phagocytes are attracted to infection sites by chemical signals d) Fusion of the phagosome with a lysosome

c) Chemotaxis, where phagocytes are attracted to infection sites by chemical signals

What structure is formed when a phagosome fuses with a lysosome? a) Phagolysosome b) Endosome c) Lysophagosome d) Granulocyte

Phagolysosome

Which of the following cells are key players in phagocytosis? a) B cells and T cells b) Natural killer cells and eosinophils c) Macrophages, neutrophils, and dendritic cells d) Mast cells and basophils

c) Macrophages, neutrophils, and dendritic cells

What is opsonization? a) The process of destroying pathogens within a phagolysosome b) Coating pathogens with molecules to enhance phagocytosis c) Binding antibodies to neutralize toxins d) The activation of Toll-like receptors on phagocytes

b) Coating pathogens with molecules to enhance phagocytosis

Which molecules act as opsonins to enhance phagocytosis? a) Cytokines and chemokines b) IgG antibodies and complement protein C3b c) Endotoxins and exotoxins d) Interleukins and interferons

b) IgG antibodies and complement protein C3b

How do opsonins improve the efficiency of phagocytosis? a) By neutralizing the pathogen’s toxins b) By increasing the number of phagocytes at the infection site c) By binding to the pathogen and facilitating recognition by phagocytes d) By triggering apoptosis of infected cells

c) By binding to the pathogen and facilitating recognition by phagocytes

Which receptor on phagocytes recognizes opsonins like antibodies? a) Toll-like receptors b) Fc receptors c) Complement receptors d) Pattern recognition receptors

b) Fc receptors

What triggers septic shock? a) Excessive antibody production b) Overwhelming immune response to infection, often caused by endotoxins or exotoxins c) Blockage of lymphatic vessels d) Chronic inflammation from autoimmune disorders

b) Overwhelming immune response to infection, often caused by endotoxins or exotoxins

Which bacterial component is commonly associated with septic shock in Gram-negative infections? a) Lipopolysaccharides (LPS) b) Peptidoglycan c) Flagellin d) Mycolic acid

a) Lipopolysaccharides (LPS)

Which type of bacteria is most affected by lysozyme? a) Gram-negative bacteria due to their lipopolysaccharide layer b) Gram-positive bacteria due to their thick peptidoglycan layer c) Acid-fast bacteria due to mycolic acid presence d) Both Gram-positive and Gram-negative bacteria equally

b) Gram-positive bacteria due to their thick peptidoglycan layer

Where is lysozyme commonly found in the body? a) Blood plasma and lymph b) Tears, saliva, and mucus c) Sweat and sebaceous glands d) Hair follicles and skin keratinocytes

b) Tears, saliva, and mucus

Why is lysozyme less effective against Gram-negative bacteria? a) They lack peptidoglycan in their cell walls. b) Their outer membrane shields peptidoglycan from lysozyme. c) Their cell walls are resistant to enzymatic hydrolysis. d) They produce enzymes that inactivate lysozyme.

b) Their outer membrane shields peptidoglycan from lysozyme.

Where do B cells mature in the human body? a) Thymus b) Bone marrow c) Spleen d) Lymph nodes

b) Bone marrow

What type of cells do activated B cells differentiate into to secrete large amounts of antibodies? a) Memory B cells b) Helper B cells c) Plasma cells d) Cytotoxic B cells

c) Plasma cells

Which function is NOT associated with antibodies produced by B cells? a) Neutralization of pathogens b) Opsonization to enhance phagocytosis c) Complement activation d) Direct killing of infected cells

d) Direct killing of infected cells

Where do T cells mature in the body? a) Thymus b) Bone marrow c) Spleen d) Peyer's patches

a) Thymus

What is the role of helper T cells (CD4+)? a) Directly killing pathogens b) Suppressing autoimmunity c) Coordinating the immune response by releasing cytokines d) Producing antibodies to neutralize toxins

c) Coordinating the immune response by releasing cytokines

What is the function of regulatory T cells? a) Activating macrophages to phagocytose pathogens b) Suppressing immune responses to prevent autoimmunity c) Presenting antigens to helper T cells d) Producing antibodies to neutralize pathogens

b) Suppressing immune responses to prevent autoimmunity

What do memory T cells provide in the immune system? a) Immediate production of cytokines during inflammation b) Long-term immunity by responding quickly to re-exposure of the same antigen c) Direct phagocytosis of pathogens during subsequent infections d) Activation of complement proteins upon re-infection

b) Long-term immunity by responding quickly to re-exposure of the same antigen

exam Flashcards

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