SEMIFINAL: Enterobacteriaceae Flashcards
These are gram negative bacilli and coccobacilli, oxidase negative, and glucose fermenter
Enteterobacteriaceae
Members of this family produce large, moist, gray colonies on nonselective media
Enterobacteriaceae except for Klebsiella and sometimes Enterobacter
Members of this family are ubiquitous in nature and reside in the gastrointestinal (GI) tract
family Enterobacteriaceae
They can be resident microbiota if confined to their natural environment
Salmonella, Shigella, and Yersinia
Based on the clinical infections that they produce, members of the family Enterobacteriacea may be divided into two broad categories:
- Opportunistic pathogens
- Primary pathogens
This category if Enterobacteriacea, is often a part of the usual intestinal microbiota of both humans and animals
Opportunistic pathogens
Outside their normal body sites, these organisms can produce serious extraintestinal, opportunistic infections
Opportunistic pathogens
What bacteria causes Urinary tract infection (UTI)?
E. coli (90%), Proteus mirabilis, and Klebsiella pneumoniae
Pneumonia is cause by what bacteria?
Klebsiella pneumoniae
Bacteremias are cause by?
E. coli, Proteus Mirabilis, Klebsiella pneumoniae (same bacteria that causes UTI)
These are antibiotic resistant genera that causes hospital acquired infections
Citrobacter, Enterobacter, and Serratia
These bacteria causes diarrhea
- Shigella spp.
- Salmonella spp.
- E. coli
- Yersinia spp.
It is enterohemorrhagic (shiga toxin producing), enterotoxigenic, enteroinvasive, enteropathogenic, and enteroadherent
E. coli
IDENTIFY:
Somatic antigen; heat- stable antigen that is located on the cell wall
O antigen
IDENTIFY:
Capsular antigen; this is a heat-labile polysaccharide found only in certain encapsulated species
K antigen
Enumerate a few examples of K antigen
- K1 antigen of E.coli
- Vi antigen of Salmonella enterica subsp. enterica serotype Typhi
This is the leading cause of community acquired urinary tract infections
Escherichia coli or E. coli
This is the primary marker of fecal contamination in water quality testing
Escherichia coli or E. coli
The major cause of E. coli-associated community-acquired urinary tract infections
Uropathogenic E. coli
The E. coli strains that cause UTIs usually originate in the _____________ as resident biota
large intestine
E. coli strains that cause UTIs can exist either as the?
predominant E. coli population or small part of the E. coli strains in the large intestine
E. coli strains that cause acute pyelonephritis in immunocompetent hosts have been shown to be the?
dominant resident E. coli in the colon
The primary virulence factor associated with the ability of E. coli to cause UTIs
Pili
This allows the uropathogenic strains to adhere to epithelial cells and not be washed out with urine flow
Pili
What are the other factors that contribute to the virulence of uropathogenic E. coli?
Cytolysins and Aerobactins
Also often characterized as hemolysins, can kill immune effector cells and inhibit phagocytosis and chemotaxis of certain white blood cells
Cytolysins
Allows the bacterial cell to chelate iron
Aerobactin
This is generally unavailable within the host for use by bacteria
Free iron
Characterized by neonatal meningitis and a positive test for the K1 antigen
Meninges/sepsis associated- E coli (MNEC)
These organisms are spread to the meninges from a blood infection and gain acess to the central nervous system via membrane-bound vacuoles in microvascular endothelial cells
Meninges/sepsis associated- E coli (MNEC)
These organisms, once inside the cell, prevent lysosomal fusion and gain access to the central nervous system
Meninges/sepsis associated- E coli (MNEC)
Enumerate the five categories that are sometimes collectively referred to as enterovirulent E. coli or diarrheagenic E. coli
- enterotoxigenic Escherichia coli (ETEC)
- enteroinvasive Escherichia coli (EIEC)
- enteropathogenic Escherichia coli (EPEC)
- enterohemorrhagic Escherichia coli (EHEC)
- enteroadherent Escherichia coli (EHEC)
What are the two subtypes of enteroadherent Escherichia coli (EHEC)
- enteroaggregative Escherichia coli (EAEC)
- Diffusely adherent Escherichia coli (DAEC)
Produces a heat-labile enterotoxin (LT) and heat-stable enterotoxin (ST)
enterotoxigenic Escherichia coli (ETEC)
Associated with cases of traveler’s diarrhea
enterotoxigenic Escherichia coli (ETEC)
This is characterized by mild, watery diarrhea; no blood nor leuocytes and abdominal cramping
Traveler’s diarrhea (associated to ETEC)