Micro - Bacteriology (Part 1) Flashcards Preview

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Flashcards in Micro - Bacteriology (Part 1) Deck (200)
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1
Q

A patient presents to your clinic with this painless lesion on his penis. What is the most likely diagnosis?

A

Syphilis

2
Q

What medication should be given for prophylaxis after a close contact is infected with the organism shown?

A

Rifampin

3
Q

A 25-year-old woman presents with vaginal discharge that looks like this on microscopy. What is your diagnosis and treatment plan?

A

Gardnerella vaginalis infection; treatment with metronidazole

4
Q

What type of organisms stain purple/blue with Gram staining?

A

Gram-positive organisms

5
Q

Gram-positive organisms are commonly classified into which two shapes?

A

Cocci or rods (bacilli)

6
Q

Name four gram-positive rods.

A

Clostridium, Listeria, Bacillus, and Corynebacterium

7
Q

Name one gram-positive anaerobic rod.

A

Clostridium

8
Q

Staphylococcus and Streptococcus are differentiated by which enzyme?

A

Catalase; Staphylococcus is catalase positive, and Streptococcus is catalase negative

9
Q

Which gram-positive cocci are found in clusters?

A

Staphylococcus

10
Q

Which gram-positive cocci are found in chains?

A

Streptococcus

11
Q

What differentiates Staphylococcus aureus from and other staph species?

A

Other staph species are coagulase negative

12
Q

Name two coagulase-negative Staphylococcus species.

A

Staphylococcus saprophyticus and Staphylococcus epidermidis

13
Q

Which Staphylococcus species is novobiocin sensitive?

A

Staphylococcus epidermidis

14
Q

Which Staphylococcus species is novobiocin resistant?

A

Staphylococcus saprophyticus

15
Q

If agar shows clear hemolysis, which Streptococcus species could be present?

A

Streptococcus pyogenes or Streptococcus agalactiae

16
Q

What type of hemolysis do both group A and group B streptococci have in common?

A

β-Hemolysis

17
Q

Streptococcus pyogenes is a type of group _____ Streptococcus, whereas Streptococcus agalactiae is a type of group _____ Streptococcus.

A

A, B

18
Q

How are -hemolytic streptococci differentiated from each other?

A

By their bacitracin sensitivity (Streptococcus pyogenes is sensitive, Streptococcus agalactiae is resistant)

19
Q

Name two streptococci that are -hemolytic.

A

Enterococcus and Peptostreptococcus (anaerobic)

20
Q

True or False: Enterococcus faecalis is a -hemolytic, gram-positive, catalase-negative cocci.

A

TRUE

21
Q

Which -hemolytic streptococcal species is bacitracin resistant?

A

Group B Streptococcus (Streptococcus agalactiae)

22
Q

Which -hemolytic streptococcal species is bacitracin sensitive?

A

Group A Streptococcus (Streptococcus pyogenes)

23
Q

Staphylococcus saprophyticus is novobiocin _____ (resistant, sensitive); staphylococcus epidermidis is novobiocin _____ (resistant, sensitive).

A

Resistant; sensitive (remember: On the staph retreat there was NO StRES; Novobiocin: Saprophyticus Resistant, Epidermidis Sensitive)

24
Q

Group A streptococci are bacitracin _____ (resistant, sensitive); group B streptococci are bacitracin _____ (resistant, sensitive).

A

Sensitive; resistant (remember: Bacitracin: group B are Resistant, whereas group A are Sensitive (B-BRAS)

25
Q

Streptococcus viridans is optochin _____ (resistant, sensitive); streptococcus pneumoniae is optochin _____ (resistant, sensitive).

A

Resistant; sensitive (remember, Optochin: Viridans Resistant and Pneumonia Sensitive; OVRPS- overpass)

26
Q

What bacterial enzyme degrades hydrogen peroxide?

A

Catalase

27
Q

What antimicrobial product produced by polymorphonuclear lymphocytes is a substrate for myeloperoxidase?

A

Hydrogen peroxide

28
Q

Which gram-positive cocci are catalase positive?

A

Staphylococci

29
Q

What differentiates Staphylococcus aureus from Staphylococcus epidermidis and Staphylococcus saprophyticus?

A

Coagulase (Staphylococcus aureus is coagulase positive)

30
Q

Why do people with chronic granulomatous disease (nicotinamide adenine dinucleotide phosphate oxidase deficiency) get recurrent infections by catalase-producing organisms?

A

Bacterial catalase easily degrades the little hydrogen peroxide produced, compromising the ability of neutrophils to kill bacteria

31
Q

What is the function of Protein A, a Staphylococcus aureus virulence factor?

A

Binding to fragment crystallizable region-immunoglobulin G, to inhibit complement fixation and phagocytosis

32
Q

Name five types of infections caused by Staphylococcus aureus.

A

Skin infections, organ abscesses, pneumonia, acute bacterial endocarditis, and osteomyelitis

33
Q

Staphylococcus aureus can cause which toxin-mediated conditions?

A

Toxic shock syndrome (toxic shock syndrome toxin 1), scalded skin syndrome (exfoliative toxin), and rapid-onset food poisoning (enterotoxins)

34
Q

Which organism produces toxic shock syndrome toxin 1?

A

Staphylococcus aureus

35
Q

What is the pathophysiology of toxic shock syndrome?

A

Toxic shock syndrome toxin 1 acts as a superantigen and causes widespread release of cytokines from T cells

36
Q

Staphylococcus aureus can cause rapid-onset food poisoning as a result of what product?

A

Preformed enterotoxins

37
Q

Methicillin-resistant Staphylococcus aureus is resistant to methicillin because of its altered structure of what protein?

A

Penicillin-binding protein

38
Q

What bacterium found in normal skin flora commonly contaminates blood cultures and infects prosthetic devices and catheters?

A

Staphylococcus epidermis

39
Q

How does Staphylococcus epidermis infect prosthetic devices and intravenous catheters?

A

By producing adherent biofilms

40
Q

What four common infections does Staphylococcus pneumoniae cause?

A

Meningitis, Otitis media, Pneumonia, and Sinusitis (remember: MOPS are Most OPtochin Sensitive)

41
Q

What is distinct about the pneumonia caused by pneumococcus?

A

"Rust"-colored sputum

42
Q

Streptococcus pneumoniae sepsis occurs at a higher rate in what two patient populations?

A

Sickle cell anemia and asplenic patients

43
Q

Name two ways Streptococcus pneumoniae evades the immune system.

A

Immunoglobulin A protease, encapsulation

44
Q

What three pyogenic infections does Streptococcus pyogenes cause?

A

Pharyngitis, cellulitis, and impetigo

45
Q

What two toxigenic diseases does Streptococcus pyogenes cause?

A

Scarlet fever and toxic shock syndrome

46
Q

What two immunologic conditions does Streptococcus pyogenes cause?

A

Rheumatic fever and glomerulonephritis (remember: PHaryngitis gives you rheumatic "PHever" and glomerulonePHitis)

47
Q

Streptococcus pyogenes is associated with what three major classes of disease?

A

Infectious, immunogenic, and toxigenic

48
Q

Human antibodies to Streptococcus M protein enhance host defenses but increase the risk for which complication of streptococcal infection?

A

Rheumatic heart disease

49
Q

What blood test would detect a recent Streptococcus pyogenes infection?

A

An antistreptolysin O titer

50
Q

Rheumatic fever is associated with what five symptoms?

A

Subcutaneous nodules, Polyarthritis, Erythema marginatum, Chorea, and Carditis (remember, there is no "RHEUM" for SPECCulation)

51
Q

Streptococcus agalactiae are bacitracin _____ (sensitive/resistant) and _____(//) -hemolytic.

A

Resistant

52
Q

In what population does group B Streptococcus (Streptococcus agalactiae) cause pneumonia, meningitis, and sepsis?

A

Babies (remember: B for Babies)

53
Q

What two infections do enterococci cause?

A

Urinary tract infection and subacute bacterial endocarditis

54
Q

How can group D enterococci be differentiated from nonenterococcal group D streptococci by lab testing?

A

Enterococci can grow in 6.5% sodium chloride, other group D streptococci cannot

55
Q

Lancefield grouping is based on differences in what components of the bacteria?

A

C carbohydrate on the bacterial cell wall

56
Q

True or False? Penicillin G is effective treatment against enterococci.

A

False; enterococci are resistant to penicillin G

57
Q

Enterococci resistant to which antibiotic are an important source of nosocomial infection?

A

Vancomycin

58
Q

What two infections does Streptococcus bovis cause in colon cancer patients?

A

Bacteremia and subacute endocarditis

59
Q

A young patient presents with pseudomembranous pharyngitis; what medium could be used to culture the most likely etiologic agent?

A

Corynebacterium diphtheriae grows on tellurite agar (coryne = club shaped)

60
Q

The symptoms of diphtheria are caused by what kind of toxin?

A

Exotoxin (encoded on the -prophage)

61
Q

How does diphtheria toxin inhibit protein synthesis?

A

By the adenosine diphosphate ribosylation of elongation factor 2

62
Q

What disease is caused by Corynebacterium diphtheriae?

A

Diphtheria; characterized by pseudomembranous pharyngitis (grayish-white membrane) with lymphadenopathy

63
Q

How is a laboratory diagnosis of diphtheria made based on microscopic appearance?

A

The presence of gram-positive rods with metachromatic granules (blue and red in color)

64
Q

How can diphtheria be prevented?

A

Toxoid vaccine; usually administered in combination with tetanus vaccine

65
Q

What type of bacteria form spores?

A

Gram-positive rods

66
Q

What advantages do bacteria gain by taking the form of a spore?

A

They become highly resistant to destruction by heat and chemicals and require no metabolic activity in nutrient-poor settings

67
Q

Why is it important to autoclave surgical equipment?

A

To kill bacterial spores

68
Q

What five soil-dwelling, gram-positive rods are spore formers?

A

Bacillus anthracis, Bacillus cereus, Clostridium perfringens, Clostridium botulinum, and Clostridium tetani

69
Q

Which bacteria are gram-positive, spore-forming, obligate anaerobic bacilli?

A

Clostridia species

70
Q

Name four clostridia species that produce exotoxins.

A

Clostridium tetani, Clostridium botulism, Clostridium perfringens and Clostridium difficile

71
Q

What kind of toxin produced by Clostridium tetani causes symptoms of tetanus?

A

An exotoxin called tetanospasmin

72
Q

Describe the pathogenesis of the symptoms caused by Clostridium tetani?

A

Clostridium tetani toxins block glycine (an inhibitory neurotransmitter) release from Renshaw cells in the spinal cord, leading to spastic paralysis, lockjaw (trismus), and risus sardonicus (remember: TETanus is TETanic paralysis)

73
Q

Which gram-positive bacilli are responsible for the flaccid paralysis caused by exposure to improperly canned foods?

A

Clostridium botulinum (remember: BOTulinum is from bad BOTtles of food)

74
Q

What are the characteristics of the toxin produced by Clostridium botulinum?

A

Preformed, heat-labile toxin

75
Q

What is the predominant symptom of botulism?

A

Flaccid paralysis

76
Q

How does the toxin produced by Clostridium botulinum cause flaccid paralysis?

A

It inhibits acetylcholine release

77
Q

How does the pathogenesis of botulism differ between adults and babies?

A

Adults consume preformed toxin whereas babies consume spores in honey (floppy baby syndrome)

78
Q

Which exotoxin-producing, gram-positive bacillus is responsible for gas gangrene?

A

Clostridium perfringens (remember: PERFringens PERForates a gangrenous leg)

79
Q

What is the effect of the toxin produced by Clostridium perfringens?

A

Toxin (lecithinase) causes myonecrosis, gas gangrene, and hemolysis

80
Q

Which gram-positive bacillus is responsible for pseudomembranous colitis?

A

Clostridium difficile (remember: DIfficile causes DIarrhea)

81
Q

Pseudomembranous colitis often follows a course of which antibiotics?

A

Clindamycin or ampicillin

82
Q

What kind of toxin is produced by Clostridium difficile?

A

A cytotoxin, which is an exotoxin that kills enterocytes and causes pseudomembranous colitis

83
Q

What is the treatment of choice for pseudomembranous colitis caused by Clostridium difficile?

A

Metronidazole

84
Q

What gram-positive, spore-forming rod that produces a toxin causes a respiratory illness that is associated with black skin lesions and exposure to animal hides and fur?

A

Bacillus anthracis

85
Q

Bacillus anthracis toxin causes what kind of skin lesion?

A

Black skin lesions (painless eschars, necrosis) surrounded by edematous ring

86
Q

The skin changes of cutaneous anthrax are caused by which two toxins?

A

Lethal factor and edema factor cause a black eschar with surrounding edema at the site of inoculation

87
Q

The inhalation of Bacillus anthracis spores leads to which symptoms?

A

Flu-like symptoms that rapidly progress to fever, mediastinitis, pulmonary hemorrhage, and shock

88
Q

What are the two modes of anthrax inoculation?

A

Cutaneous and pulmonary

89
Q

What is Woolsorters disease?

A

Pulmonary infection of Bacillus anthracis due to inhalation of spores from contaminated wool

90
Q

How is the capsule produced by Bacillus anthracis unique?

A

It is the only bacterium to have a polypeptide capsule (contains D-glutamate)

91
Q

What diseases does Listeria monocytogenes cause in pregnant women?

A

Amnionitis, septicemia, and spontaneous abortions

92
Q

How does the disease caused by Listeria monocytogenes differ among adults, neonates, and immunocompromised individuals?

A

In healthy individuals it causes a mild gastroenteritis but can cause meningitis in neonates and immunocompromised patients

93
Q

How is Listeria monocytogenes acquired?

A

By ingestion of unpasteurized milk, cheese, or deli meats or by vaginal transmission during birth

94
Q

How does Listeria monocytogenes move from cell to cell?

A

Listeria is an intracellular organism that induces "actin rockets" to move into new cells

95
Q

Listeria monocytogenes has what identifying characteristic on microscopy?

A

Tumbling motility

96
Q

What distinguishes Listeria monocytogenes from all other gram-positive bacteria?

A

It is the only gram-positive bacterium to have an endotoxin

97
Q

Which two bacteria are gram-positive rods that form long-branching filaments that resemble fungi?

A

Actinomyces israelii and Nocardia asteroides

98
Q

Which is an anaerobe: Actinomyces israelii or Nocardia asteroides?

A

Actinomyces israelii

99
Q

Which is a weakly acid-fast aerobe in soil: Actinomyces israelii or Nocardia asteroides?

A

Nocardia asteroides

100
Q

Describe the lesions caused by Actinomyces israelii.

A

Oral/facial abscesses that may drain through sinus tracts

101
Q

True or False? Actinomyces are part of the normal oral flora.

A

TRUE

102
Q

What type of disease does Nocardia asteroides cause in immunocompromised individuals?

A

Pulmonary infection

103
Q

How are infections with Actinomyces israelii and Nocardia asteroides treated?

A

SNAP: Sulfa for Nocardia; for Actinomyces, use Penicillin

104
Q

What is a characteristic finding in the draining sinuses caused by Actinomyces israelii infection?

A

Yellow "sulfur granules"

105
Q

What two mycobacteria species are often resistant to multiple drugs?

A

Mycobacterium tuberculosis and Mycobacterium avium-intracellulare

106
Q

What symptoms are caused by Mycobacterium kansasii?

A

Pulmonary tuberculosis-like symptoms

107
Q

Infection with Mycobacterium avium-intracellulare is symptomatic in which patient group?

A

Patients with AIDS

108
Q

What are the symptoms of tuberculosis?

A

Fever, night sweats, weight loss, and hemoptysis

109
Q

Describe the leonine facies of leprosy caused by Mycobacterium leprae.

A

Loss of eyebrows, nasal collapse, and lumpy earlobe

110
Q

What is another name for leprosy?

A

Hansens disease

111
Q

The organism that causes leprosy has what animal reservoir in the United States?

A

Armadillos

112
Q

Because Mycobacterium leprae likes cool temperatures, it tends to infect what areas of the body?

A

The skin and the superficial nerves

113
Q

What is the treatment of choice for leprosy?

A

Long-term oral dapsone

114
Q

What toxicity is associated with long-term oral dapsone treatment?

A

Hemolysis and methemoglobinemia

115
Q

What are two alternative treatment options for leprosy?

A

Rifampin and the combination of clofazimine and dapsone

116
Q

What are the two forms of Hansens disease?

A

Lepromatous and tuberculoid

117
Q

Which of the two forms of leprosy indicates failed cell-mediated immunity and has a worse prognosis?

A

Lepromatous = Lethal

118
Q

Which of the two forms of leprosy is self-limited?

A

Tuberculoid

119
Q

True or False? Mycobacterium leprae can be grown in vitro.

A

FALSE

120
Q

How can the skin lesions of lepromatous and tuberculoid leprosy be differentiated?

A

Lepromatous skin lesions present diffusely over the skin and are communicable (failed cell-mediated immunity) whereas tuberculoid skin lesions are limited to a few hypoesthetic nodules

121
Q

Gram-negative organisms can be classified into what three shapes?

A

Cocci, coccoid rods, and rods

122
Q

Name four organisms that are gram-negative, coccoid rods.

A

Haemophilus influenzae, Bordetella pertussis, Pasteurella, and Brucella

123
Q

What is a common source of Pasteurella infections?

A

Animal bites

124
Q

Name two gram-negative cocci.

A

Neisseria meningitidis and Neisseria gonorrhoeae

125
Q

How are the two gram-negative cocci differentiated from each other?

A

By maltose fermentation (Neisseria meningitidis is a maltose fermenter; Neisseria gonorrhoeae is not)

126
Q

Gram-negative rods are differentiated by the fermentation of what substance?

A

Lactose

127
Q

Name three fast lactose-fermenting, gram-negative rods.

A

Klebsiella, Escherichia coli, and Enterobacter

128
Q

Name two slow lactose-fermenting, gram-negative rods.

A

Citrobacter and Serratia

129
Q

Among nonlactose fermenters, the presence of what substance can be used to differentiate Pseudomonas from Shigella, Salmonella, and Proteus?

A

Oxidase (Pseudomonas is oxidase positive, Shigella, Salmonella, and Proteus are oxidase negative)

130
Q

What type of bacteria grows pink colonies on MacConkeys agar?

A

Lactose-fermenting enteric bacteria

131
Q

Name five bacteria that grow pink colonies on MacConkeys agar.

A

Citrobacter, Klebsiella, Escherichia coli, Enterobacter, and Serratia (remember: test with MacConKEES)

132
Q

True or False? Gram-negative organisms are resistant to penicillin and all of its derivatives.

A

False; some gram-negative organisms are susceptible to penicillin derivatives such as ampicillin

133
Q

What part of gram-negative organisms inhibits the entry of penicillin G and vancomycin?

A

The outer membrane

134
Q

Neisseria meningitides _____ (does/does not) have a polysaccharide capsule; Neisseria gonorrhea _____ (does/does not) have a polysaccharide capsule.

A

Does; does not

135
Q

Neisseria meningitides _____ (does/does not) have a vaccine; Neisseria gonorrhea _____ (does/does not) have a vaccine.

A

Does; does not

136
Q

Neisseria meningitides _____ (does/does not) ferment lactose; Neisseria gonorrhea_____ (does/does not) ferment lactose.

A

Does; does not

137
Q

What five types of infection can Neisseria gonorrhea cause?

A

Gonorrhea, pelvic inflammatory disease, septic arthritis, Fitz-Hugh-Curtis syndrome, and neonatal conjunctivitis

138
Q

What three clinical syndromes can Neisseria meningitides cause?

A

Septicemia, meningitis, and Waterhouse-Friderichsen syndrome

139
Q

How is Neisseria gonorrhoeae transmitted?

A

Sexually transmitted

140
Q

How is Neisseria meningitidis transmitted?

A

Respiratory and oral secretions

141
Q

Why can a vaccine to Neisseria gonorrhea not be created?

A

Rapid antigenic variation

142
Q

Name four diseases that can be caused by Haemophilus influenzae.

A

Epiglottitis, Meningitis, Otitis media. and Pneumonia (remember: HaEMOPhilus)

143
Q

What is the method of transmission of Haemophilus influenzae?

A

Aerosol

144
Q

Which type of Haemophilus influenzae causes the most invasive disease?

A

Capsular type B

145
Q

Escherichia coli, Salmonella, Shigella, Klebsiella, Enterobacter, Serratia, and Proteus belong to which bacterial family?

A

Enterobacteriaceae

146
Q

All species in the enterobacteriaceae have what type of antigen?

A

Somatic (O) antigen, which is the endotoxin polysaccharide

147
Q

All enterobacteriaceae species ferment _____ and are oxidase _____.

A

Glucose; negative

148
Q

What is the somatic (O) antigen?

A

The polysaccharide of endotoxin

149
Q

What does the capsular (K) antigen tell you about the enterobacteriaceae species?

A

Certain K antigens are correlated with more virulent species

150
Q

Motile enterobacteriaceae species have what type of antigen?

A

Flagellar (H) antigen

151
Q

Aside from diarrhea/dysentery, what diseases does Escherichia coli commonly cause?

A

Cystitis, pyelonephritis, pneumonia, neonatal meningitis, and septic shock

152
Q

What three types of Escherichia coli do not invade the intestinal mucosa?

A

Enterohemorrhagic, enterotoxigenic, enteropathogenic; only enteroinvasive Escherichia coli invades the mucosa

153
Q

Which Escherichia coli species produces shiga-like toxin?

A

Enteroinvasive and enterohemorrhagic Escherichia coli

154
Q

What differentiates the disease caused by enteroinvasive Escherichia coli and enterohemorrhagic Escherichia coli?

A

Both cause dysentery, but with enteroinvasive, both the toxin and the microbe cause necrosis and inflammation; with enterohemorrhagic, only the toxin does

155
Q

Which toxins mediate the diarrhea caused by enterotoxigenic Escherichia coli?

A

Labile toxin/stable toxin

156
Q

What disease is caused by enterotoxigenic Escherichia coli?

A

Travelers diarrhea

157
Q

How does enteropathogenic Escherichia coli cause diarrhea?

A

It adheres to the apical surface, flattens villi, decreasing absorption (this is NOT toxin mediated)

158
Q

What population tends to get diarrhea following enteropathogenic Escherichia coli infection?

A

Children

159
Q

What potentially fatal systemic complication can be caused by enterohemorrhagic Escherichia coli infection?

A

Hemolytic uremic syndrome

160
Q

A seven-year-old child has a burger at a barbeque and subsequently develops diarrhea. He then ceases urinating, becomes lethargic, and is found to have low red blood cell and platelet counts. What is your diagnosis?

A

Hemolytic uremic syndrome secondary to infection with enterohemorrhagic Escherichia coli

161
Q

What is the pathophysiology of hemolytic uremic syndrome?

A

Endothelial swelling and narrowing leads to mechanical hemolysis (anemia) and reduced renal blood flow (acute renal failure), with damaged endothelium consuming platelets (thrombocytopenia)

162
Q

What bacteria classically causes "red currant jelly" sputum in a patient with pneumonia?

A

Klebsiella

163
Q

An alcoholic man is admitted to the hospital with fever, dyspnea and is coughing up gelatinous red sputum. Chest x-ray is consistent with an abscess. What infection do you suspect?

A

Klebsiella (remember the "4 As": Abscess, Alcoholic, Aspiration, and diAbetics)

164
Q

Klebsiella is a cause of what other nosocomial infection in addition to pneumonia?

A

Urinary tract infection

165
Q

What do Salmonella and Shigella have in common?

A

They are both nonlactose-fermenting bacteria that invade the intestinal mucosa causing bloody diarrhea

166
Q

Which of the following is motile and can disseminate hematogenously: Salmonella or Shigella?

A

Salmonella

167
Q

How does Shigella propel itself within the cell?

A

By actin polymerization

168
Q

Which antibiotics should be used to treat salmonellosis?

A

Salmonellosis should not be treated with antibiotics; doing so can prolong symptoms

169
Q

Which leukocyte response is seen in salmonellosis?

A

Monocyte response

170
Q

Which is more virulent: Salmonella or Shigella?

A

Shigella (101 Shigella organisms vs 105 Salmonella organisms)

171
Q

Which has an animal reservoir: Salmonella or Shigella?

A

Salmonella (except Salmonella typhi, which is only found in humans); Salmonella is often acquired from reptiles and poultry

172
Q

What are the modes of transmission of Shigella?

A

The "4 Fs": Food, Fingers, Feces, and Flies

173
Q

A woman presents to the clinic with fever, diarrhea, headache, and rose spots on her abdomen. What is the likely diagnosis?

A

The woman has typhoid fever caused by Salmonella typhi

174
Q

Chronic carriers of Salmonella harbor the bacteria where in their bodies?

A

The gallbladder

175
Q

What mode of propulsion do Salmonella use to disseminate?

A

Flagella

176
Q

What are the usual modes of transmission of Yersinia enterocolitica?

A

Pet feces (eg, puppies) and contaminated milk or pork

177
Q

Yersinia enterocolitica outbreaks are common in what setting?

A

Day-care centers

178
Q

Yersinia enterocolitica infections can mimic what other diseases, particularly in teenagers?

A

Crohns disease or appendicitis

179
Q

Heliobacter pylori causes what two pathologies in the gastrointestinal tract?

A

Duodenal ulcers and gastritis

180
Q

Heliobacter pylori is a urease _____ (positive/negative), gram _____ (positive/negative) _____ (rod/cocci).

A

Urease-positive, gram-negative rod

181
Q

What enzyme in Helicobacter pylori helps to create an alkaline environment?

A

Urease

182
Q

Heliobacter pylori is a risk factor for what two cancers?

A

Gastric adenocarcinoma and lymphoma

183
Q

A patient with a chronic ulcer is found to have a positive urease breath test. How would you treat the patient?

A

Triple therapy: (1) Bismuth, metronidazole, and either tetracycline or amoxicillin; or (2) (more costly) metronidazole, omeprazole, and clarithromycin

184
Q

What are the three spirochete species that most commonly affect humans?

A

Borrelia (Big size), Leptospira, and Treponema (remember: BLT)

185
Q

What is the only spirochete that can be visualized by light microscopy with aniline dyes (ie, Wrights or Giemsa staining)?

A

Borrelia (remember: Big size)

186
Q

Which spirochete species is visualized by dark-field microscopy?

A

Treponema, which causes syphilis

187
Q

A farmer in the tropics with contaminated water sources presents with fever, headache, abdominal pain, photophobia, and conjunctivitis. What infection do you suspect?

A

Leptospira

188
Q

Leptospirosis is most prevalent in which geographical locations?

A

The tropics

189
Q

What is Weils disease?

A

Severe leptospirosis, which presents with severe jaundice, azotemia, fever, hemorrhage, and anemia

190
Q

What is another name for Weils disease?

A

Icterohemorrhagic leptospirosis

191
Q

Where is Leptospira interrogans commonly found in the environment?

A

In water contaminated with animal urine

192
Q

What is the cause of azotemia and jaundice in patients with Weils disease?

A

Renal and liver failure

193
Q

The organism that causes Lyme disease is transmitted by what vector?

A

The Ixodes tick

194
Q

What bacteria causes Lyme disease?

A

Borrelia burgdorferi

195
Q

The classic symptom of Lyme disease, erythema chronicum migrans, has what appearance?

A

An expanding "bulls eye" red rash with central clearing

196
Q

What organs are affected in patients with Lyme disease?

A

The skin, the joints, the central nervous system, and the heart

197
Q

Which mammals are required for the life cycle of the Ixodes tick?

A

Deer and mice

198
Q

What are the treatments of choice for Lyme disease?

A

Doxycycline and ceftriaxone

199
Q

In what region of the United States is Lyme disease common?

A

The northeastern United States

200
Q

What are the three stages of Lyme disease and their associated symptoms?

A

Stage 1: erythema chronicum migrans and flu-like symptoms;

stage 2: neurologic and cardiac manifestations;

stage 3: autoimmune migratory polyarthritis