Gram Negative Flashcards by Luke Cielonko

Gram negative, diplococci; glucose oxidizer; grows on Thayer-Martin media; causes STD; high variability of microbial antigenic structure

Neisseria gonorrhoeae

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Gram negative, diplococci; glucose and maltose oxidizer; grows on Thayer-Martin media; causes petecial rash, meningitis, and Waterhouse-Friderichsen syndrome

Neisseria meningitidis

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Gram negative rod; lactose non-fermenter; produces H2S; motile; cause of gastroenteritis; gained from undercooked chicken or turtles

Salmonella etneritidis

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Treatment for Salmonella enteritidis

fluid and electrolytes

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What antigen is found on the flagella of Salmonella enteritidis?

H antigen

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Gram negative rod, non-lactose fermenter, H2S producer, cause of thyphoid fever

Salmonella typhi

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what is the path of infection for Salmonella typhi?

1) Fecal-oral route
2) Taken up by macrophages in the peyer’s patches
3) Spread via phagocytes to gallbladder, liver, and spleen
4) Releases its endotoxin causing rose spots, fever, diarrhea, and abdominal pain

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Rose spots, fever, diarrhea, and abdominal pain

Typhoid fever caused by Salmonella typhi

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What is the carrier state found in Salmonella typhi?

1) It is where Salmonella that entered phagocytes and travel to the gallbladder remain their
2) They may reenter the bowel lumen and spread through feces

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What do sickle cell pt. get with a Salmonella typhi infection?

Osteomyelitis

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Gram negative bacteria; lactose fermenter; pili and flagella present; capsule present; May cause UTI or enteritis; contracted from hamburger meat

Escherichia coli

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E. coli that adhere to GI tract but do not invade; produce heat labile toxin/ heat stabile toxin (similar to cholera toxin); causes watery diarrhea

Enterotoxigenic E. coli (ETEC)

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E. coli that adhere to GI tract; secrete Shiga-like toxins; causes inflammtation and bleeding; does not ferment sorbitol and does not produce glucuronidase

Enterohemorrhagic E. coli (EHEC)

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What happens when Shiga-like toxins enter the blood stream?

Hemolytic uremic Syndrome- causes damage to the kidneys

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Fever, hemolytic anemia, thrombocytopenia, and acute renal failure; occurs after diarrheal/flu symptoms

Typical Hemolytic Uremic Syndrome

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Gram negative rod; lactose fermenter; large capsule; causes currant jelly sputum; atypical pneumonia; may also causes UTI

Klebsiella pneumoniae

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Common bacteria found in alcoholics; results in atypical pneumonia

Klebsiella pneumoniae

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What is the treatment for Klebsiella

3rd gen cephalosporin

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Gram negative diplococci; oxidase positive; has specialized pili and capsule; causes otitis media, sinusitis, and pneumonia

Moraxella catarrhalis

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2nd most common cause of bacterial pneumonia in COPD pt.

Moraxella catarrhalis

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Otitis media, sinusitis, and pneumonia

Moraxella catarrhalis

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Gram negative rod; does not ferment lactose, oxidase negative, does not produce H2S and non motile; causes bloody diarrhea

Shigella dysenteriae

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How does the Shiga toxin work?

It inactivates 60s ribosomes

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Gram negative rod, does not ferment lactose, oxidase negative, urease positive; motile with many flagella

Proteus mirabilis

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What can proteus mirabilis cause?

1) Struvite stones | 2) UTI (alkaline urine)

How are struvite stones formed?

1) Formed in increased pH due to urease activity of P. mirabilis 2) Urease splits urea to ammonium

Gram negative rod, non-lactose fermenter, oxidase positive, glucose fermenter; rice water diarrhea; comma shaped, single flagella; able to grow in alkaline rich medium

Vibrio cholerae

How does the cholera toxin work?

1) Increases Gs protein causing adenylate cyclase to be active increasing cAMP 2) Results in increased secretion of Cl leading to increased water loss

Gram negative rod, non-lactose fermenter, oxidase positive, non-glucose fermenter; blue-green colonies; burn wounds, endocarditis, pneumonia, external otitis, diabetic osteomylitis

Pseudomonas aeruginosa

Gram negative rod; non-lactose fermenter, mobile at 25 and non-mobile at 37; causes bloody diarrhea and mesenteric adenitis; may cause appendicitis like pain

Yersinia enterocolitica

Where does Yersinia enterocolitica localize?

Terminal ileum and then may travel to mesenteric lymph nodes by lymphatics

Gram negative, coccobacilli, pleomorphic; growth on charcoal yeast agar; causes pontiac fever and atypical pneumonia; naturally inhabits water reservoirs (air conditioners, cruise ships); causes hyponatremia with pneumonia

Legionella pneumophila

How does Legionella pneumophila causes Legionnaire's disease?

1) Inhaled from respiratory devises/air conditioners 2) Adheres to respiratory epithelium via pilli 3) Phagocytosed by alveolar macrophages 4) Infected macrophages secrete neutrophil chemoattractants 5) Neutrophils arrive and form microabscesses

Acute flu-like illness lasting 2-5 days caused by a gram negative cocobacilli; may have gastric problems as well

Legionella pneumophila

Gram negative rod; cause of bubonic plague; has a capsular F-1 antigen that prevents phagocytosis; bipolar staining; resemble safety pin

Yersinia pestis

Describe the process of infection for Yersinia pestis

1) Transferred via tick 2) Phagocytized and tranported to regional lymph nodes 3) Regional lymphadenitis (buboes) occur in the groin 4) Intracellular replication occurs 5) Spread to liver, spleen, skin, and lungs 6) Endotoxin causes DIC 7) Cutaneous hemorrhagic necrosis causing black color

Gram negative rod with filamentous hemagglutin; growth on Bordet-Gengou medium; cause of whooping cough

Bordetella pertusis

How does Bordetella pertussis adhere to cilia of respiratory epithelium?

Filamentous hemaglutin

How does the pertusis toxin decrease phagocytosis?

1) Pertusis toxin causes inactivation of the Gi protein resulting in uninhibited adenylate cyclase causing increased cAMP which causes lymphocytosis and decreased phagocytosis

What are the three stages of whooping cough?

1) Catarrhal stage (1-2 weeks) - flu like symptoms 2) Paroxysmal stage (3 week - 2 months) intermittent bouts of many coughs on a single expiration followed by whooping 3) Recovery stage

Cause of undulating fever

Brucella

Fever that climbs during the day and declines at night

Undulating fever

What is the most common cause to contract Brucella?

1) Ingestion of goat cheese

Gram negative rod that requires cysteine for growth, facultative intracellular organism; cause of tularemias

Francisella tularenis

Organism primarily passed by ticks in rabbits; devolps into ulcer with black base and lymphadenopathy

Francisella tularensis

What are the clinical findings of a Bartonella henselae infx?

1) Regional lymphadenopathy 2) Fever of unknown origin 3) Ocular involvement 4) Hepatosplenomegaly

Cause of Cat Scratch Disease

Bartonella henselae

Gram negative coccobacilli; oxidase and catalse positive; contracted by animal bite; causes cellulitis and osteomyelitis

Pasteruella multocida

Gram negative rod; urease positive, curved and small; increased risk of PUD

Helicobacter pylori

Gram negative rod, S shaped; urease negative, curved and small; polar flagellum; causes blood or secretory diarrhea; grows best at 42 degrees

Campylobactor jejuni

Gram negative rod; strict anaerobe; normal flora of the GI; causes abscesses when rupture occurs; abscess acts as reservoir for organisms

Bacterioides fragilis

Only gram negative without endotoxin

Bacteroides fragilis

Gram negative rod that requires chocolate agar for growth and factors V(NAD) and X(hematin); Positive Quellung test

think: when child has "flu" mom goes to five (V) and dime (X) shops to buy chocolate Haemophilus influenzae

How do inhaled H. influenzae get protection from IgA? What other organisms has this protection?

1) IgA protease | 2) Neiserria meningitidis

Cause of epiglottitis; otitis media; pneumonia; meningitis, septic arthritis, and cellulitis

Haemophilus influenzae

Most common causes of meningitis in children 6 months to 6 years

1) Streptococcus pneumoniae 2) Nesseirria meningitidis 3) Haemophilus influenzae

What are the structural characteristics of gram negative bacteria?

1) LPS is present | 2) Thin cell wall

What does LPS consist of?

1) Lipid A (endotoxin) | 2) Polysaccharide

Diagnostic test in which specific antiserum causes the capsule to swell

Quellung reaction

Treatment for Haemophilus influenzae

Third generation cephalosporin (ceftriaxone)

Treatment for Bacteroides fragilis?

1) Drain abscess | 2) Tazobactam and Piperacillin

Treatment of Campylobacter jejuni

1) Erythromycin (macrolide, inhibit 50s subunit) | 2) Ciprofloxacin (Fluoroquinolone- DNA gyrase)

What is the treatment of heliobacter pylori?

1) PPI + amoxicillin + clarithromycin | 2) PPI + BMT

Treatment for Haemophilus influenzae type b

1) third generation cephalosporin (ceftriaxone) | 2) rifampin for prophylaxis

Treatment for Moraxella catarrhalis

1) amoxicillin + clavulanate (beta lactamase inhibitor) | 2) ceftriaxone

Treatment for Klebsiella pneumoniae

Third generation cephalosporin

Treatment for Neisseria gonorrhoeae

1) ceftriaxone

Treatment for Pseudomonas aeruginosa

1) anti-pseudomonal penicillin + aminoglycoside | 2) fluoroquinolone

Treatment for legionella pneumophilla

1) Erythromycin (inhibits ribosome 50s subunit) Think a "wreath" is laid down by the legionnaire's grave

Woman from Arkansas presents with a small persistent black ulcer. Axillary lymph nodes enlarged on same side. Believed to be caused by a tick bite that occurred while caring for rabbits

Francisella tularenis

Woman has flu-like illness. She complains of a fever that rises during the day and peaks after dinner. Lymph nodes are enlarged. Woman ate goat cheese at a local French village?

Undulating fever + goat cheese = | Brucella infection

Treatment for Proteus mirabilis?

TMP-SMX (inhibits formation of tetrahydrofolate; trimethoprim + sulfamethoxazole)

Treatment for UTI caused by E. coli?

TMP/SMX

Treatment for meningitis/sepsis caused by E. coli?

Ceftriaxone

Rice water diarrhea

Vibrio cholerae

Treatment for Francisella tularensis?

1) Streptomycin (aminoglycoside)

Cause of Waterhouse-Friderichsen syndrome

Neisseria meningitidis

PRP (Polyribosyl-ribitol-phosphate)

H. influenzae

What does H. influenze require for growth?

1) NAD | 2) Hematin (blood)

What is the function of IgA protease?

1) It facilitates mucosal penetrance | 2) IgA is found in dimer form in the mucosa and prevents infiltration of organisms

Complications of Pseudomonas

Think: BE PSEUDO 1) Burn infections 2) External otitis 3) Pneumonia 4) Endocarditis 5) UTI 5) Diabetic Osteomyelitis

How does Pseudomonas exotoxin work? What gram positive exotoxin works similarly?

1) Exotoxin A inhibits EF2 | 2) Corynebacterium diphtheria

Microorganism that is visualized with silver stain and demonstrates growth on media with cysteine and buffered by charcoal yeast extract agar

Legionella penumophila

What gram negative bacteria are the lactose fermenters?

think: EKES! lactose! 1) E. coli 2) Klebsiella 3) Enterobacter 4) Serratia

What gram negative bacteria are non-lactose fermenters and oxidase negative?

think: SSP 1) Shigella 2) Salmonella 3) Proteus mirabilis

What gram negative bacteria are comma shaped

1) Vibrio cholera | 2) Campylobacter jejunum

What should you think with ecthyma gangrenosum (dark spots with black centers)

Pseudomonas

What does Haemophilus type b cause speciically?

1) Sepsis 2) Meningitis 3) Pneumonia

What can cause Bacillary angiomatosis

Bartonella hensalae

Pt. presents with red-purple papular skin lesions that may also be found within the viscera. Fatal if untreated

Bacillary angiomatosis

What results from consumption of raw oysters?

1) Vibrio parahaemolyticus

Pneumonia with fever of 104, smoker, accompanied with diarrhea, confusion, and cough

Legionella pneumophelia

Bacteria that causes hyponatermia

Legionella pneumophelia

Gram Negative Flashcards

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