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)
This is characterized by watery diarrhea, abdominal cramps, and sometimes nausea, usually with no vomiting or fever
Mild, self-limiting disease caused by ETEC
Characterized by watery to bloody diarrhea which is similar to shigella, it is RBC positive and WBC positive
enteroinvasive Escherichia coli (EIEC)
EIEC may produce a watery to bloody diarrhea as a result of direct invasion of the _______________ of the colon similar to _______________
Epithelial cells and Shigella spp., respectively
Produce dysentery with direct penetration, invasion, and destruction of the intestinal mucosa
Enteroinvasive strains
Charactarized by attachment and effacement lesion in the colon
enteropathogenic Escherichia coli (EPEC)
Characterized by prolonged (chronic), non bloody diarrhea; vomiting; and fever. IT is typical in infants or children
enteropathogenic Escherichia coli (EPEC)
The stool in this diarrhagenic E. coli typically contains large amounts of mucus but apparent blood is not present
enteropathogenic Escherichia coli (EPEC)
Pediatric diarrhea, foodborne outbreaks, and diarrhea in HIV- infected and AIDS patients. Stool in this diarrhagenic E. coli is not bloody and does not contain white blood cells
enteroadherent Escherichia coli (EAEC)
This gene in EAEC is responsible for cellular adherence
AggR gene
It produces hemorrhagic colitis and hemolytic uremic syndrome (HUS)
Shiga toxin-producing E. coli (STEC)
It is characterized by a hemolytic anemia and low platelet count and can often results to kidney failure and death
Hemolytic uremic syndrome (HUS)
Unlike in dysentery, no white blood cells are found in the stool of this diarrheagenic E. coli
Shiga toxin-producing E. coli (STEC); HUS
_________ is a component of the lipopolysaccharide of the outer membrane and the _________ is the specific flagellin associated with the organism
O antigen (156 serotypes) and H antigen (56 serotypes)
Characterized by live abscesses, pneumonia, septicemia, and urinary tract infections
Klebsiella spp.
Carry a heat-labile cytotoxin, which has been isolated from patients who have developed a self-limiting antibiotic associated hemorrhagic colitis
K. oxytoca
Characterized by community-acquired pyogenic liver abscesses and hypervirulent phenotype (hVKP)
K. pneumoniae
These have the ability to spread in healthy patients because of an intrinsic resistance to serum complement and the bactericidal effects of neutrophils
hvKP clinical variants
A Klebsiella sp., that is resistant to ampicillin
K. pneumoniae
K. pneumoniae may demonstrate multiple antibiotic resistance patterns from the acquisition of _______________ with enzymes such as ____________ and ______________
Multidrug-resistant plasmids; carbapenemase; cephalosporinases (in order)
Contains Klebsiella organisms and are increasingly isolated from community-acquired pyogenic liver abscesses worldwide and demonstrate a hypervirulent (hypermucoviscous) phenotype (hvKP)
K1 capsular clonal complex (CC23k1)
Associated with severe pnemonia and bloodstream infections
K1 capsular clonal complex (CC82k1)
A Klebsiella sp., that can be visualized in scrapings of lesions and is stained with wright or giemsa stain
Klebsiella granulomatis
This Klebsiella sp., is unculturable
K. granulomatis
K. granulomatis is an agent of?
Donovanosis or granuloma inguinale
Groups of this organisms are seen within mononuclear endothelial cells and is knowns as?
Donovan body
This organism staains as a blue rod with prominent polar granules, giving rise to a ‘‘safety pin’’ appearance and is surrounded by a large pink capsule
Donovan body
One of the most commonly isolated healthcare-associated infections
Enterobacter spp.
It is associated with contaminated medical
devices such as respirators and other medical instrumentation
Enterobacter spp.
These organisms are ingested from water, vegetable, and food products
Enterobacter spp.
Characterized by acute inflammatory colitis &
bloody diarrhea characterized by cramps, tenesmus, bloody & mucoid stool
Dysentery (in Shigella spp.)
A type of shigella spp. that may produce watery diarrhea
Shigella sonnei.
Infections are associated with consumption of
contaminated food such as meat and dairy
products
Hafnia Alvei
Most infections with these bacteria are identified in patients with severe underlying disease (e.g., malignancies) or after surgery or trauma
H. alvei
Often associated with stool specimen from patients with symptoms of diarrhea
Morganella spp.
An emerging enteric pathogen associated with food-and water-borne illness. Causes gastroenteritis, most
commonly in children
Pleasiomonas shigelloides
A freshwater inhabitant that is transmitted to humans by ingestion of contaminated water or by exposure of disrupted skin and mucosal surface
Pleasiomonas shigelloides
Often associated with urinary tract infections; however, it is isolated from wounds and ears. This is also associated with diarrhea and sepsis
Proteus spp.
These bacteria are easily identified by their classic “swarming” appearance on culture media
Proteus spp.
Known for colonization and the cause of pathogenic infection in health care setting
Serratia marcescens
Serratia spp. are resistant to ampicillin and first-generation
cephalosporins because of the presence of an?
AmpC beta-lactamase
This specie of Salmonella is associated with a severe disease called typhoid
Salmonella serotype typhi
These are not associated with typhoid fever
Diarrhea and vomiting
IDENTIFY:
The symptoms are often headache, abdominal cramping, constipation, and high fever. The patient may present with a rash and appear confused. Human carriers have been identified. The disease is transmitted person-to-person or through contaminated food and water
typhi or typhoid fever
These are facultative anaerobic, motile, gram-negative rods commonly isolated from the intestines
of humans and animals
Salmonella (all serotypes)
Serotypes are differentiated based on the characterization of?
- heat-stable O antigen,
included in the LPS - heat-labile H antigen flagellar protein
- heat-labile Vi antigen, capsular polysaccharide.
Serotyping in Shigella spp. is based on the?
Somatic LPS O antigen
Dysentery with stools that contain blood or mucus
Shigellosis
The most severe form of Shigella
S. dysenteriae 1
IDENTIFY:
May begin as watery diarrhea, fever, and abdominal cramps. Progressive infection then leads to dysentery with stools that contain blood or mucus. Lesions in the intestinal tract typically remain confined to the large intestine.
Bloodstream infections are rare
Shigellosis
These are capable of causing dysentery
All Shigella spp.
Out of all the Shigella spp., this is the one that produces the most severe forms of illness and may lead to hemolytic uremic syndrome (HUS)
S. dysenteriae 1
Most commonly transmitted by the bite of an infected flea resulting in bubonic plague
Y. pestis
Handling infected animals, inhaling infectious droplets, and ingestion of undercooked meat have resulted in this infection
Y. pestis
Human-to-human transmission is possible with the pneumonic (respiratory) form of disease.
Y. pestis
This is found in the gastrointestinal tract of swine, rodents, and dogs
Y.enterocolitica
Found in a variety of wild and domesticated animals including rodents, birds, and rabbits
Y. pseudotuberculosis