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ENTEROBACTERIACEAE Flashcards

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1
Q

Characteristics of ENTEROBACTERIACEAE

A
  • Non acid fast gram (-) baccili
  • Commonly present in large intestine
  • Non-spore forming gram – rods
  • all are glucose fermenters, reduces nitrates to nitrites, oxidase (-)
  • grows on bile containing agar
  • motile except Shigella & Klebsiella
  • non-capsulated except Kelbsiella
  • non sporeforming
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2
Q

Cell wall -outer membrane of

ENTEROBACTERIACEAE

A

LPS (heat stable)
– O polysaccharide
– Core polysaccharide
– Lipid A

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3
Q

Lipid A

A

outer wall coponent responsible for producing fever and shock; inflammatory effect

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4
Q

Serological Identification of ENTEROBACTERIACEAE

A

– O polysaccharide
– K antigen
– H proteins

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5
Q

Virulence Factors of ENTEROBACTERIACEAE

A

O antigen, or somatic antigen- heat stable
H antigen, or flagellar antigen- heat labile
K antigen, or capsular antigen - heat labile
LPS (Lipid A)

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6
Q

Porins

A

Found on the outer membrane of cell wall that acts as sieve, allowing water-soluble mol. to enter cell

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7
Q

Lactose Fermenters Enterobacteriaceae

A

E.coli & Escherichia, Klebsiella

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8
Q

Late Lactose Fermenters Enterobacteriaceae

A

Shigella sonnei

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9
Q

Non-Lactose Fermenters Enterobacteriaceae

A

Salmonella & Shigella

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10
Q

MacConkey Agar

A
  • bile containing agar
  • selective and differential culture medium for bacteria
  • designed to selectively isolate some Gram-positive and enteric
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11
Q

Lactose fermenters:
morphology

E. COLI

A
  • appear in single or pairs
  • motile by petrichate flagella
  • 1-3 x 0.4-0.7 microns
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12
Q

Lactose fermenters: E.COLI

Culture characteristic

A
  • grows between 10-40 c optimal at 37
  • grown in simple medium
  • large grayish, thick-white moist smooth opaque colonies
  • may sometimes contain capsule
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13
Q

Lactose Fermenters in MacConkey Agar

A
  • Briight Pink colonies
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14
Q

Non- Lactose Fermenters in MacConkey Agar

A

Colorless colonies

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15
Q

Lactose fermenters: E.COLI

on Blood Agar

A
  • many strains are haemolytic on blood agar
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16
Q

Lactose fermenters: E.COLI

Biochemical Characteristics

A
  • Glucose, lactose, mannitol, and lactose fermenters
  • Citrate/ urease not produced
  • A/G indole + methyl red + voges Proskauer
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17
Q

Lactose fermenters: E.COLI

Antigenic structure

A

K - capsular 100
H - flagellar 75
O - somatic 170
Virulence factors

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18
Q

Antigen of Enterobacteriaceae that protects the bacteria from phagocytosis

A

K antigen (capsular)

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19
Q

Antigen of Enterobacteriaceae that is important in cases of UTI

A

H antigen (flagellar spcifically fimbriae)

  • absent in Shigella spp.
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20
Q

Antigen of Enterobacteriaceae that promotes endotoxic activity

A

O antigen (somatic)

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21
Q

Antigen of Enterobacteriaceae that is absent in shigella spp.

A

H antigen

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22
Q

Antigen of Enterobacteriaceae that present in extraintestinal infections caused by E. coli?

A

K antigen (capsular)

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23
Q

An isolated organism shows a negative lactose fermentation and negative in motility test. Which among the choices is the presumptive organism?

Salmonella spp.
Shigella spp.
Escherichia spp.

A

Shigella spp

  • non lactose and non-motile

Escherichia is lactose fermenter
Salmonella is non-lactose fermenter but it is motile.

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24
Q

Virulence factor of E.coli that is present in large numbers and can cause mannose sensitive haemagglutination

A

Fimbriae

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25
What strain of E.coli produce enterotoxin
Enterotoxigenic strains (ETEC)
26
E.coli produces these toxins which causes a movement of water and ions from the tissues to the bowel resulting in watery diarrhea
Enterotoxin
27
Types of E.coli involved in different types of gastroenteritis
``` Shiga toxin-producing E. coli (STEC)—STEC may also be referred to as Verocytotoxin-producing E. coli (VTEC) or enterohemorrhagic E. (EHEC) Enterotoxigenic E. coli (ETEC) Enteropathogenic E. coli (EPEC) Enteroaggregative E. coli (EAEC) Enteroinvasive E. coli (EIEC) ```
28
Types of E.coli: Enteropathogenic EPEC
- EPEC 026/011 - produce Verocytotoxin - frequent in summer months - brush border of intestine is lost - Intimacin (EPEC adhesion factor)
29
Types of E.coli: Identification Enteropathogenic EPEC
- serotyping for B and o ags. - routine culture for isolation - fails to ferment sorbitol
30
Types of E.coli: Lab diagnosis Enteropathogenic EPEC
- Confirm (Polyvalent sera) - test sero groups w/ polyvalent and monovalent sera - HEp2 adherence
31
Enteropathogenic EPEC adhesion factor
Intimacin
32
Enterotoxigenic ETEC adhesion factos
Fimbriae specific receptors | CFA mortality in children
33
Types of E.coli: Enterotoxigenic ETEC
- produce heat stable/ heat labile toxins - HL like cholera toxin - causes accumulation of fluids - adheres to epithelium of sm
34
Types of E.coli: Lab diagnosis Enterotoxigenic ETEC
- Demonstration of Enterotoxin LT nd ST in tissue culture test - Passive agglutination test - Animal experiments in rabbit ileal loop test
35
Types of E.coli: Enteroinvasive (EIEC)
- resembles shigella - non lactose fermenter & non-motile - penetrate HeLa cells
36
Types of E.coli: Lab diagnosis Enteroinvasive (EIEC)
- Sereny test positive animal rabbit | - ELISA
37
Type of E.coli that is non lactose fermenter and non-motile
ENTEROINVASIVE E. COLI (EIEC)
38
Types of E.coli: Enterohemorrhagic (EHEC)
- produce verocytotoxin or shiga like toxin - hemorrhagic complication with 0157; H7 - present in human and animal feces - disease may manifest as food poisoning
39
Type of E.coli that produces verocytotoxin
Enteropathogenic EPEC | Enterohemorrhagic (EHEC)
40
Types of E.coli: Lab diagnosis Enterohemorrhagic (EHEC)
- DNA detection method - ctotoxic effects on vero cells - Detection w/ monovalent sera 0157/ h7
41
Type of diarrhea associated with EIEC
- mild diarrhea to frank dysentery
42
Type of diarrhea associated with ETEC
- travelers diarrhea | - present with nausea, vomiting and lose stool
43
Type of diarrhea associated with EPEC
- diarrheal disease in children | - infantile enteritis
44
Type of diarrhea associated with EHEC
- mild diarrhea; can be fatal hemorrhagic colitis and uremic syndrome
45
Type of diarrhea associated with EAEC
- persistent diarrheal
46
Types of E.coli: Enteroaggresive EAEC
- appear aggregated in S stacked brick formation hep-2 cell | - produce weight heat stable enterotoxin called as low molecular heat stable enterotoxin
47
Types of E.coli: Lab diagnosis Enteroaggresive EAEC
- Stool culture | - Detection of Enterotoxin
48
Leading cause of urinary tract infection which can lead to acute cystitis (bladder infection) and pyelonephritis (kidnet infection)
E. coli infections
49
Specimen used for Culturing of E.coli
- Mid stream sample of urine - culture by standard loop method - Antibiotic sensitivity tested
50
Which of the following choices grows on SMAC (MacConkey) Blood culture for EHEC Urine culture for EIEC Stool culture for EHEC Urine culture for EHEC
Stool culture for EHEC
51
Most commonly islated spp of Klebsiella
K. pneumoniae
52
Small cracks in the medium with black precipitates Which E coli strains causes infantile diarrhea? EHEC EPEC ETEC EAEC
EPEC
53
Which member of Enterobacterales has a positive result on Neufeld Quellung test? * ``` Escherichia coli Proteus vulgaris Klebsiella pneumoniae Shigella dysenteriae Salmonella enteritidis ```
Klebsiella pneumoniae
54
Lactose fermenters: Klebsiella morphology
- has polysaccharide capsule - has distinctive "yeasty" odor - non motile - has moist and mucoid in its colonies
55
Enterobactericiae spp that is the frequent cause of nosomical pneumonia, speticemia, and meningitis
Klebsiella spp
56
Lactose fermenters: Klebsiella Virulence factors
- capsule - adhesions - iron capturing ability
57
Lactose fermenters: Klebsiella Significant biochemical reactions
- lactose positive - Citrate (+) - non motile - urease (+) - has both O and K antigens - LIA K/K
58
Slow lactose fermenters: Serratia spp
- 7 spp. but S.marcescnes is the only clinically important - produce pink pigment esp. when cultures are left at room temp. - fairly resistant to antibiotics
59
Non-lactose fermenters: Hafnia spp
- H.alvei is the only specie - occasionally isolated from stools - delayed citrate reaction is major characteristic
60
pathogens of Enterobacteriaceae family that are part of normal intestinal flora---- also called as opporunistic pathogen
Proteus, Morganella, and Providencia spp. - they deaminate phenylalanine
61
Non-lactose fermenters | Enterobacteriaceae
- Hafnia spp - Proteus - Morganella - Providencia -
62
Non-lactose fermenters: Proteus spp. P. mirabilis P. vulgaris
- isolated from urine, wounds, and ear - both produces swarming colonies on non-selective media - distinctive "burned chocolate" odor - both urease (+) - both are phenylalanine deaminase (+)
63
Widely recognized Proteus spp human pathogens
P. mirabilis | P. vulgaris
64
Non-lactose fermenters: Proteus spp. Biochemical characteristic
A- exhibits "swarming" | B shows urease (+) on right
65
Non-lactose fermenters: Morganella spp.
- Morganella morganii is the only specie - urease (+) - phenylalanine deaminase (+) - isolated from other anatomical sites
66
Non-lactose fermenters: Providencia rettgeri
- pathogen of urinary tract and has caused nosomical outbreaks - phenylalanine deaminase (+)
67
Non-lactose fermenters: Providencia stuartii
- can cause nosomical outbreaks in BURN units nad has been isolated from urine - phenylalanine deaminase (+)
68
Late lactose fermenters: Citrobacter spp.
- C. freundii - resembles salmonell spp. - hydrolyze urea slowly - differentiated by their ability to convert tryptophan to indole
69
A magenta color develops after incubating inoculated bacteria throughout the medium for urea utilization. Which species would give such a result? * ``` Providencia spp. Pasteurella spp. Hemophilus spp. Pseudomonas spp. Proteus spp. ```
Proteus spp.
70
Links:
https: //www.austincc.edu/microbugz/negative_stain.php https: //drive.google.com/file/d/1MsBlYPVAYmg87vapD5WkkPl2wJHAipPA/view

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