Gram-Negative Bacilli, Non-spore forming Flashcards
All members are non-encapsulated except for
Klebsiella and Enterobacter
Most of them are present in the intestinal tract as commensal microbiota except for
Plesiomonas, Salmonella, Shigella, and Yersinia
Some organisms like? may grow at 1C to 5C
Serratia and Yersinia
Biochemical test: (+) catalase; (-) oxidase except for
Plesiomonas shigellosis
They are not present as commensal microbiota of the human GIT
Overt/True Pathogens
They are acquired through ingestion of contaminated food or water
Overt/True Pathogens
Their presence in specimens is considered as very significant
e: E.coli, Citrobacter, Enterobacter, Klebsiella, Proteus, and Serratia
2.
Example of Overt/True Pathogen
Salmonella, Shigella, and Yersinia pestis
They are part of the intestinal microbiota of both humans and animals
They generally do not initiate disease in healthy, uncompromised human host
Oppurtunistic Pathogens
They may produce serious extraintestinal infection outside their normal body sites
They produce significant virulent factors
Opportunistic pathogens
Examples of Oppurtunistic pathogens are
: E.coli, Citrobacter, Enterobacter, Klebsiella, Proteus, and Serratia
heat-stable; located in the cell wall; used for E.coli and Shigella serotyping
Somatic O antigen
- heat-labile; found in the flagellum; used for Salmonella serotyping
Flagellar H antigen-
-heat-labile polysaccharide; found as K1 antigen of E.coli and Vi antigen of
S. entrica subsp. enterica serotype typh
Capsular K antigen
It may inhabit the female genital tract, although it is a microbiota of the large intestine
Escherichia coli
It is a primary indicator of fecal contamination in water purification
It is the leading cause of nosocomial urinary tract infection
Escherichia coli
It has both the sex pili and adhesive fimbrae
Escherichia coli
EMB-Colonies exhibit a greenish metallic sheen
Escherichia coli
IMViC- ++/–
TSIA reaction: A/A (acidic slant/acidic butt), (+) gas, (-) hydrogen sulfide or H2S
Escherichia coli
Pili that permit gastrointestinal colonization, Heat- Labile and Heat-stable enterotoxins that mediate secretion of water and electrolytles into the bowel lumen
Enterotoxigenic E.coli
Virulence factors uncertainm but organism invades enterocytes lining the large intestine in a manner nearly identical to shigella
Enteroinvasice E.coli
Bundle-forming pilus, intimin and other factors that mediate organism attachment to mucosal cells of the small bowel, resulting in changes in cell surface
Enteropathogenic E.coli
Toxin similar to Shiga toxin produced by Shighella dysenteriae. Most frequently associates with certain serotypes such as E.coli O157:H7
Enterohemorrhagic E.coli
Probably involves bindin by Pili, ST-like and hemolysin-like toxins, actual pathogenic mechanism is unkown
Enteroaggregative E.coli