Term
Enterobacteriaceae generalities
-morphology
-transmission
-metabolism
-toxins
-clinical
-diagnostics
-antigenic classification |
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Definition
Gram-negative rods
fecal-oral migration up the urethra, colonization of catheters
Catalase-positive
Oxidase-negative
ferments glucose
facultative anaerobic
many have enterotoxins
all have endotoxin: LPS
many cause diarrhea
also UTI, pneumonia, sepsis
EMB: inhibitory to gram-pos bacteria
MacConkey agar: inhibit gram-pos bacteria
O-Ag: outer portion of LPS
K-Ag: Kapsule
H-Ag: flagella |
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Term
E. coli
reservoir
transmission
metabolism
virulence
toxins
clinical
diagnostics
misc |
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Definition
humans: GI and urinary tract
fecal-oral
migration up the urethra
colonization of catheters in hospitalized patients
aspiration of oral E. coli
Beta-hemolytic
ferments lactose
fimbriae (pili): colonization
siderophore
adhesins
K-antigen
H-antigen
Enterotoxins:
LT (heat labile, i/c cAMP)
ST (heat stable, i/c cGMP)
Shiga-like toxin: inhibits pr synthesis by inactivating 60S ribosomal subunit
Newborn meningitis
UTI
Hospital acquired sepsis, pneumonia
Diarrhea
-ETEC: LT, ST, traveler's
-EHEC: bloody, no fever/pus, Shiga-like toxin, hemorrhagic colitic, hemolytic uremic syndrome, O157:H7
EIEC: bloody, pus, fever, + fecal leukocytes
Gram stain
culture: urine, sputum, CSF, or blood
Stool
EMB: metallic sheen
MacConkey: pink-purple
index organism for fecal contamination of H2O |
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Term
Klebsiella pneumo
metabolism
virulence
clinical
misc |
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Definition
Ferments lactose
Capsule
Nonmotile
Pneumonia: lung necrosis, bloody sputum, commonly in alcoholics or those with underlying lung disease
Nosocomial UTI and sepsis
Alcoholics |
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Term
Shigella dysenteriae
reservoir
transmission
metabolism
virulence
toxins
clinical
diagnostics
misc |
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Definition
Humans
fecal-oral
Does not ferment lactose
Ferments glucose
Oxidase-neg
Invades submucosa of intestinal tract
No H-Ag
Shiga toxin: inactivates 60S ribosome, inhibiting protein synth and killing intestinal epithelial cells
Bloody diarrhea with mucus and pus (similar to EIEC), + fecal leukocytes
Never part of NF in stool
Culture is diagnostic
IgA is best for immunity |
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Term
Salmonella typhi
reservoir
transmission
metabolism
virulence
clinical
diagnostics
misc |
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Definition
S. typhic only in humans
Non-typi Salmonella: zoonotic, uncooked eggs
Fecal-oral
Does not ferment lactose
Ferments glucose
H-Ag +
Capsule (VI Ag), protects from intracellular killing
Siderophore
Typhoid Fever: fever, ab pain, liver or spleen enlargement, Rose spots on abdomen
Paratyphoid fever: caused by non-typhi Salmonella
Chronic carrier state
Gastroenteritis
Sepsis
Osteomyelitis: esp in sickle cell patients
Culture: blood, stool or urine may contain S. typhi
never part of NF
Facultative intracellular parasite - lives within macrophages in lymph nodes
Can live in gallbladder for year (carriers)
Those who are asplenic or with sickle cell anemia are at i/c risk of infxn |
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Term
Yersinia enterocolitica
reservoir
transmission
metabolism
virulence
toxins
clinical
diagnostics
misc |
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Definition
Zoonotic: pigs
contaminated food or water
unpasteurized milk
Non-lactose fermenter
Virulence factors are expressed at 37C
V and W antigens
motile
Enterotoxin similar to heat stable toxin of E. coli: i/c cGMP levels
Acute enterocolitis: fever, diarrhea, ab pain
stool or blood may be +
colonscopy: mucosal ulceration
can survive refrigeration
closely related to Yersinia pestis |
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Term
Vibrio cholerae
transmission
morphology
metabolism
virulence
toxins
clinical
diagnostics |
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Definition
fecal-oral
short comma shaped, gram-neg rod with a single polar flagellum
ox-pos
ferments sugars (but not lactose)
motile (H Ag)
mucinase: digests mucous layer so V. cholerae can attach
Fimbriae: attachment
Noninvasive
Choleragen (enterotoxin): like LT of E. coli, i/c cAMP, causing secretion of electroyltes
Cholera: severe diarrhea with rice water stool, no pus
Dark field microscopy of stool: motile organisms immobilized with antiserum
selective media: TCBS agar |
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Term
Campylobacter jejuni
reservoir
transmission
morphology
metabolism
virulence
toxins
clinical
diagnostics
misc |
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Definition
zoonotic: esp poultry
uncooked meat (esp poultry)
unpasteurized milk
fecal-oral
curved gram-neg rods
single polar flagellum
microaerophilic
ox-pos
motile, H-Ag
Invasive
Enterotoxin: similar to cholera toxin and the LT of E. coli
Cytotoxin: destroys mucosal cells
Secretory or bloody diarrhea
Microscopic exam of stool: motile, curved gram-neg rods
Selective media with antibiotics at 42C - fastidious, req's special medium
one of the 3 most common causes of diarrhea in the world |
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Term
Helicobacter pylori
morphology
metabolism
clinical |
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Definition
curved gram-neg rods
tuft of polar flagellum
microaerophilic
urease-pos
duodenal ulcers
chronic gastritis |
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Term
Pseudomonas aeruginosa
metabolism
virulence
toxins
clinical
diagnostics
misc |
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Definition
obligate aerobe
ox-pos
non-lactose fermenter
doesn't ferment glucose
motile (polar flagellum)
Hemolysin
Collagenase
Elastase
Fibrinolysin
Phospholipase C
DNAase
some have antiphagocytic capsule
Exotoxin A (similar to diphthera toxin): inhibits protein synth by EF2
Pneumonia
-CF patients, immunocompromised
Osteomyelitis
-diabetic pts, IV drug users, children
Burn wound infxns
Sepsis
UTI
Endocarditis (IV drug abusers)
Malignant external otitis
Corneal infxns in contact lens wearers
Culture: greenish-metallic colonies on blood agar, fruity (grape) smell
Opportunistic pathogen
Produces pigments when cultured:
-Pyocyanin: blue
-Pyoverdin: fluorescent green |
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Term
Bacteroides fragilis
transmission
metabolism
toxins
clinical
diagnostics
misc |
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Definition
part of NF of intestine
Anaerobic
Gram-neg rod
Non-spore former
Polysaccharide capsule
Doesn't contain lipid A, no endotoxin
Abscesses in GI tract, pelvis, lungs
Gram-stain
Anaerobic culture
Infxn occurs when organism enters into the peritoneal cavity |
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