Enterobacteriaceae Flashcards
Identify the E.coli strain with this description:
Major agent of “traveler’s diarrhea” + has two exotoxins (heat-labile and heat-stable) resulting in fluid loss
Enterotoxigenic E.coli
False about Escherichia coli
A. Facultative anaerobe
B. All strains are pathogenic
C. Lactose fermenters
B. All strains are pathogenic
Some even compete with pathogens!
Identify the E.coli strain with this description:
A.adheres to mucosa of small bowel
B.adherence factors lead to loss of microvilli & formation of filamentous actin structures
C. Cause watery diarrhea in developing countries, esp infants
Enteropathogenic E.coli
Identify the E.coli strain with this description:
• has invasive factor that destroy mucosa –> bloody diarrhea
• may ferment lactose or not
• non-motile
Enteroinvasive E.coli
Most common and impt isolate of EHEC, causes hemorrhagic colitis, haemolytic uremic syndrome + thrombocytopenic
E.coli O157:H7
False abt lab diagnosis of E.coli O157:H7
A. Sorbitol positive colonies formed
B. Use of SMAC or CT-SMAC
C. Both are false
A. Sorbitol positive colonies formed
Negative dapat
False about Enterobacteriaceae A) ferment glucose B) all are non-motile C) oxidase negative D) reduce nitrate E) catalase positive
B) all are non-motile
Some have peritrichous flagella
Capsules are large and regular in \_\_\_ species A)Shigella B)Enterobacter C)Klebsiella D)Salmonella
C)Klebsiella
False about Escherichia coli A. Positive for indole B. Produces gas from glucose C. Negative for lysine decarboxylase D. Ferments mannitol
C. Negative for lysine decarboxylase
Positive dapat
False about Klebsiella group A. Mucoid growth B. motile C. Positive for citrate D. Large polysacch capsules
B. motile
False about Enterobacter group A. Motile B. Positive for citrate C. No gas prod fr glucose D. Positive for ornithine decarboxylase
C. No gas prod fr glucose
True or false: Klebsiella-Enterobacter-Serratia group produces negative Voges-Proskauer reaction.
False
False about Proteus-Morganella-Providencia group A. Deaminate phenylalanine B. Non-Motile C. Grow on KCN D. Ferment xylose
B. Non-Motile
Proteus has ___ flagella
Peritrichous
I. Proteus
II. Morganella
III. Providencia
Which are usually urease positive?
I & II
I. Proteus
II. Morganella
III. Providencia
Which have little to no lactose fermentation?
I and III
True or false: Citrobacter decarboxylases lysine and ferments lactose quickly.
False. Both actions are false.
False about O antigen A. Most external part of cell wall B. Resistant to heat and alcohol C. Detected by bacterial agglutinatiob D. Antibodies: primarily IgG
D. Antibodies: primarily IgG
IgM dapat
True or false: a single organism may carry several O antigens
True
False about K antigens A. External to O antigens in all Enterobacteriaceae B. Some are polysacch, others:protein C. External part of Klebsiella's capsule D. May be assoc with virulence
A. External to O antigens in all Enterobacteriaceae
All –> some
False about H antigens A. Found in flagella B. Resistant to heat and alcohol C. Agglutinate with IgG D. May undergo phase variation
B. Resistant to heat and alcohol
False about bacteriocins A. Production controlled by nucleus B.also called colicins C. Pore-forming toxins D. Can be used for "typing" of organisms
A. Production controlled by nucleus
Plasmids dapat
True or false: Most UTIs are caused by small number of O antigen types that specifically elaborated virulence factors of growth/subsequent infection
True
True or false
Hemolysin facilitates tissue invasion; it is cytotoxic
True
Which toxin of ETEC is this? • under genetic control of plasmid • subunit B attaches to cell • subunit A activates adenyl cyclase • too much water, Cl secreted and too little Na reabsorbed • antigenic
Heat-labile exotoxin
Which toxin of ETEC is this?
• under genetic control of heterogenous grp of plasmids
• activates guanyl cyclase in enteric epith –> fluid secretion
Heat-stable enterotoxin
Which is false?
A.no heat-stable positive strains produce heat-labile exotoxins
B.strains with both toxins produce more severe diarhea
A.no heat-stable positive strains produce heat-labile exotoxins
No –> many
What strain of E.coli is this?
• cause acute/chronic diarrhea in persons in developing countries
• specific patterns of aherence
• diagnosis confirmed via tissue culture adhesion assays (not commercially available)
Enteroaggregative E.coli
False about Klebsiella pneumoniae
A. May cause hemorrhagic and necrotizing consolidation of the lung
B. May produce UTI/bacteremia in debilitated patients
C. Not found in feces of healthy people
D. None of the above
C. Not found in feces of healthy people
Found in feces of about 5% of normal individuals
False about granuloma inguinale
A. Caused by Klebsiella granulomatis
B. Uncommon sexually transmitted transmitted disease
C. Grows with ease on egg yolk media
D. Ampicillin/tetracycline: effective treatment
C. Grows with ease on egg yolk media
Ease –>difficulty
False about Enterobacter group
A. Ferment lactose
B. May have capsules that produce mucoid colonies
C. Non-motile
C. Non-motile
Chromosomal beta lactamase in Enterobacter species that renders them intrinsically resitant to ampicillin and first/second gen cephalosporin
AmpC
Identify this Gram negative rod
A.common opportunistic pathogen in hospitalized patients
B.may cause bacteremia,pneumonia and endocarditis
C. 10% of isolates form prodigiosin (red pigment)
D. Can be treated with third gen cephalosporin
Serratia marcascens
False about Proteus species A. P.mirabilis causes UTI B. P.vulgaris is a nosocomial pathogen C.produce urease D.has slow motility
D.has slow motility
Slow –>rapid
Which is false?
A. Proteus mirabilis is often inhibited by penicillin
B. Providencia species are not part the normal flora
C. Providencia species are often resistant to antimicrobial therapy
D. Aminoglycosides and cephalosporins may be used to treat infections caused by Proteus species
B. Providencia species are not part the normal flora
