Ch. 20 - Enterobacteriaceae Flashcards
Cytochrome oxidase reaction of enterics
Cytochrome oxidase negative
Carbohydrate fermented by all enterics
Glucose
Enterics that do not reduce nitrates to nitrites
- Erwinia
- Pantoea agglomerans
Non-motile enterics
- Shigella
- Klebsiella
Structure that enables enterics to be motile
Pili (fimbriae)
Gram reaction of enterics
Gram negative
Oyxygen requirements of enterics
Facultatively anaerobic
Culture media used for presumptive identification of enterics
- MAC
- HEA
- XLD
Rapid fermenting enterics
- Klebsiella
- Escherichia
- Enterobacter
Late fermenting enterics
- Citrobacter
- Hafnia
- Pantoea
- Serratia
Non-fermenting enterics
- Proteus
- Edwardsiella
- Morganella
- Providencia
- Yersinia
- Salmonella
- Shigella
Heat-stable antigen; located on the cell wall; made up of lipopolysaccharide (LPS)
O antigen/somatic antigen
Heat-labile antigen on the surface of flagella; structures responsible for motility; made up of proteins
H antigen/flagellar antigen
Heat-labile antigen; found in capsular polysaccharide; covers the O antigen
K antigen/capsular antigen/envelope antigen
Place where O/somatic antigen is found
Cell wall
Substance that makes up O/somatic antigen
Lipopolysaccharide (LPS)
Place where H/flagellar antigen is found
Surface of flagella
Substance that makes up H/flagellar antigen
Proteins
Place where K antigen is found
Capsular polysaccharide
Heat-stable antigen
O/somatic antigen
2 heat-labile antigens
- H/flagellar antigen
- K/capsular/envelope antigen
Organ where E. coli is commonly isolated from
Colon
Antigens of E. coli used for the identification of strains associated with serious enteric disease
O and H antigens
Antigen of E. coli that masks O antigen during bacterial agglutination by specific antiserum
K antigen
Carbohydrates fermented by E. coli
- glucose
- lactose
- trehalose
- xylose
IMViC results for E. coli
I: +
M: +
V: -
C: -
Most common cause of UTIs in humans
Uropathogenic E. coli
Virulence factors for uropathogenic E. coli
- pili
- cytolysins
- aerobactin
Virulence factor of uropathogenic E. coli which allows adherence to epithelial cells
Pili
Virulence factor of uropathogenic E. coli that kills immune effector cells and inhibits phagocytosis and chemotaxis of certain WBCs
Cytolysins
Virulence factor of uropathogenic E. coli that allows the bacterial cell to chelate iron
Aerobactin
E. coli that causes diarrhea of infants and adults in tropical and subtropical climates
Enterotoxigenic E. coli (ETEC)
Common names of the disease caused by ETEC
- Traveler’s diarrhea
- Montezuma’s Revenge
- Turista
2 types of toxins produced by ETEC
- heat-labile toxin (LT)
- heat-stable toxin (ST)
Fragment of heat-labile toxin of ETEC that activates adenylate cylase; causes hypersecretion of electrolytes and fluid (watery diarrhea); ATP to cAMP
A (active)
Fragment of heat-labile toxin of ETEC that confers specificity; provides entry for the A portion
B
Toxin by ETEC that stimulates guanylate cylase which causes increased production of cGMP
Heat-stable toxin (ST)
The only E. coli strain that grows in blood agar
ETEC
E. coli strain with the same toxins with Vibrio cholerae
ETEC
E. coli strain that is Shigella-like
Enteroinvasive E. coli (EIEC)
Test previously used to determine virulence of Shigellae and EIEC
Sereny Test
Test used to detect the invasiveness of EIEC
Monolayer cell cultures with human epithelial-2 cells (Hep-2)
E. coli strain that causes the stool to have large amounts of mucus but no blood
Enteropathogenic E. coli (EPEC)
E. coli strain that is noninvasive and does not produce toxins
EPEC
Test used yo identify EPEC
Serologic typing with pooled antisera
Other name of Enterohemorrhagic E. coli (EHEC)
E. coli 0157:H7
Former name of EHEC
Verotoxic E. coli (VTEC)
2 cytotoxins produced by EHEC
- verotoxin I
- verotoxin II
Cytotoxin by EHEC that is phage-encoded identical yo Shiga toxin (Stx); damages Vero cells; neutralized by the antibody against Stx
Verotoxin I
Cytotoxin by EHEC; biologically similar but immunologically different from Stx; AKA Shiga toxigenic E. coli
Verotoxin II
Appearance of EHEC from stool culture in SMAC
Colorless
Culture medium used to identify EHEC
SMAC (MAC agar containing sorbitol)
2 types of Enteroadherent E. coli
- diffusely adherent E. coli (DAEC)
- enteroaggregative (EAEC)
E. coli strain associated with both UTI(chronic or reccuring) and diarrheal disease; causes cystitis in children and acute pyelonephritis in pregnant women
Diffusely adherent E. coli (DAEC)
Disease caused by DAEC in children
Cystitis
Disease caused by DAEC in pregnant women
Acute pyelonephritis
E. coli strain that packs in an aggregative “stacked brick” pattern; causes diarrhea by adhering to the surface of the intestinal mucosa (Hep2 cells)
Enteroaggregative E. coli (EAEC)
Escherichia sp. isolated from CSF, wounds and blood; yellow-pigmented
E. hermannii
Escherichia sp. isolated from humans with infected wounds; yellow-pigmented colonies
E. vulneris
Escherichia sp. associated with diarrheal disease in children
E. albertii
6 genus under Tribe Klebsiella
- Klebsiella
- Cronobacter
- Hafnia
- Enterobacter
- Pantoea
- Serratia
MRVP reaction of Tribe Klebsiella
MR (-) and VP (+)
Most commonly isolated Klebsiella sp.
K. pneumoniae
Substance that makes up the capsule of K. pneumoniae
Polysaccharide
Organism that frequently causes lower respiratory tract infections among hospitalized patients and immunocompromised hosts
K. pneumoniae
Klebsiella sp. that is identical to K. pneumoniae; indol (+) and ornithine (+); from blood and stool cultures
K. oxytoca
Klebsiella sp. responsible for atrophy of the nasal mucous membranes with fetid odor; isolated from blood and stool cultures
K. ozanae
Klebsiella sp. that causes Rhinoscleroma; causes destructive granuloma of the nose and pharynx
K. rhinoscleromatis
Infection of the nasal cavity that manifests as an intense swelling and malformation of the entire face and neck
Rhinoscleroma
2 Klebsiella sp. isolated from urine, blood and the respiratory tract
- K. ornithinolytica
- K. planticola
2 culture media for the growth of Tribe Klebsiella
- Simmons citrate agar
- potassium cyanide broth
Enterobacter sp. that is the predominant isolate; causes UTI and wound infections
E. cloacae
Enterobacter sp. that resembles E. aerogenes; has strong urease activity
E. gergoviae
Enterobacter sp. that causes endocarditis and meningitis
E. aerogenes
Enterobacter sp. that resembles E. cloacae; yellow-pigmented; associated with neonatal sepsis
E. sakazakii
Enterobacter sp. that causes osteomyelitis following traumatic wounds; lactose negative; ONPG positive
E. taylorae (E. cancerogenus)
Organism from Tribe Klebsiella that is associated with contaminated IV fluids; yellow-pigmented; negative to ADH, LDH and ODC
Pantoea agglomerans
Serratia sp. that causes pneumonia and septicemia; clinically significant
S. marcescens
Serratia sp. that ferments arabinose
S. liquefaciens
Serratia sp. that has rancid or potato-like odor; ferments sucrose, raffinose and ornithine
S. odorifera
Part of Tribe Klebsiellae that is not known to cause gastroenteritis but occasionally isolated from stool cultures
Hafnia
Hafnia sp. that is negative to lactose, sucrose, sorbitol, citrate, DNAse, and lipase
H. alvei
Hafnia sp. that grows in beer wort of breweries; not isolated clinically
H. alvei biotype 1
3 genera under Tribe Proteeae
- Proteus
- Providencia
- Morganella
MRVP reaction of Tribe Proteeae
MR (+) and VP (-)
Urease activity of Proteus
Rapid
Genera in Tribe Proteeae that causes acute glomerulonephritis
Proteus
2 Proteus sp. with ‘swarming’ motility in BA
- P. mirabilis
- P. vulgaris
Distinct odor of P. mirabilis and P. vulgaris
Burnt chocolate
2 Proteus sp. that are H2S+
- P. vulgaris
- P. mirabilis
Indole and ornithine reactions of P. mirabilis
Negative indole, positive ornithine
Indole and ornithine reactions of P. vulgaris
Positive indole, negative ornithine
Proteus sp. isolated from patients with diarrhea
P. penneri
Proteus sp. isolated from gypsy moths; characterized by large amounts of slime it produces
P. myxofasciens
Morganella sp. documented to cause UTI but has not been isolated
M. morganii
Providencia sp. associated with UTI and occasional nosocomial outbreaks
P. rettgeri
Providencia sp. associated with nosocomial outbreaks in burn units; isolated from urine cultures
P. stuartii
Edwardsiella sp. that is a human pathogen; source of GI infection, wound infections and abscesses; biochemically similar to E. coli; does not grow in Simmons citrate
E. tarda
Edwardiella sp. that is isolate from snakes, birds and water
E. hoshinae
Edwardsiella sp. that causes enteric septicemia in fish
E. ictaluri
Medium where all Citrobacter sp. will grow
Simmons Citrate agar
Citrobacter sp. that can be isolated in diarrheal stool cultures; extraintestinal pathogen; associated with endocarditis in IV drug abusers
C. freundii
Citrobacter sp. that is responsible for nursery outbreaks of neonatal meningitis and brain abscesses
C. diversus (C. koseri)
Colony description of Salmonella
Metallic colonies with black ring (BSA and BGA)
What substance inhibits the growth of Salmonella sp. in media?
Potassium cyanide
3 antigenic structures of Salmonella spp.
- Somatic O antigens (Groups A, B, C, and D)
- Flagellar H antigen (1, 2, 3, and 4)
- Vi antigen
Phase of Flagellar H antigen of Salmonella spp.; occurs only in small number of serotypes; antigens agglutinate only with homologous antisera; specific phase
Phase 1
Phase of Flagellar H antigen of Salmonella spp.; occurs among several strains; reacts with heterologous antisera; non-specific phase
Phase 2
Antigenic structure of Salmonella; surface polysaccharide capsular antigen; prevents phagocytosis; often blocks O antigen during serologic typing; can be removed by heating
Vi antigen
Salmonella sp. that causes enteric fever: typhoid and paratyphoid
S. typhi
Salmonella sp. that causes septicemia
S. choleraesuis
Salmonella spp. that causes gastroenteritis
- S. typhimurium
- S. enteritidis
An agglutination test for the presence of antibodies against Salmonella organisms that cause typhoid fever
Widal Test
Antigen in Widal test that signifies active infection of Salmonella spp.
O antigen
Antigen in Widal test that signifies past immunization or infection
H antigen
Antigen in Widal test that signifies of being a carrier
Vi antigen
Test for Salmonella spp. endotoxins; amebocytes of horse crab (visible gel)
Limulus Test
Test for Salmonella spp. enterotoxins; ballooning of the intestinal tract (accumulation of fluid)
Ileal Loop Test
Bacillary dysentry caused by Shigella spp.; bloody, mucoid diarrheic stool with pus cells and fishy odor
Shigellosis
Shigella sp. that is most prevalent in the US; releases beurotoxin and enteroxin
S. dysenteriae
2 toxins produced by S. dysenteriae
- beurotoxin
- enterotoxin
Yersinia sp. that caused the Black Death
Yersinia pestis
2 stains used fot Y. pestis; bipolar staining (intense staining)
- methylene blue
- Wayson stain
Appearance of Y. pestis after staining with Wayson stain or methylene blue
Safety-pin appearance
Yersinia sp. with stalactite patterns
Y. pestis
3 forms of Y. pestis
- bubonic/glandular
- septicemic
- pneumonic
Yersinia sp. associated with enterocolitis; ingestion of contaminated water, pork, beef or milk products; fecal-oral transmission
Y. enterocolitica
Colony appearance of Y. enterocolitica
Red “bull’s-eye” colonies with colorless halo (CIN medium)
Yersinia sp. that causes lymphadenitis in children
Y. psedotuberculosis
Yersinia sp. that spreads to mesenteric lymph nodes when ingested; caseuos swelling
Y. pseudotuberculosis