members of the family enterobacteriaceae
DESCRIPTION
Members of the Family Enterobacteriaceae. Citrobacter. Resembles Salmonella but are ONPG (+) & LDC (-) Citrobacter species freundii (UTI, pneumonia, intraabdominal abscess) diversus (neonatal meningitis) amalonaticus (extraintestinal infections) C. freundiiS. diversus H2S+- - PowerPoint PPT PresentationTRANSCRIPT
MEMBERS OF THE FAMILY ENTEROBACTERIACEAE
Citrobacter Resembles Salmonella but are ONPG (+)
& LDC (-) Citrobacter species
freundii (UTI, pneumonia, intraabdominal abscess)
diversus (neonatal meningitis)amalonaticus (extraintestinal infections)
C. freundiiS. diversusH2S+-
Indole-+KCN+-
KlebsiellaKlebsiella -Enterobacter-Serratia-Hafnia
K. pneumoniae>Friedlander’s bacilli (encapsulated and
mucoid)> (+) String test
Klebsiella aerogenes is associated with hospital acquired infections of wounds and of the urinary tract
K. rhinoschleromatis – rhinoscleromatis (granulomatous disease of the nose and pharynx
with intense swelling and malformation of the entire face and neck)
The patient's K. pneumoniae isolate was string test positive (>5 mm
string length).
LABORATORY DIAGNOSES Specimens: Depending on the site of infection, specimens include urine, pus, sputum and infected tissue. Morphology Klebsiellae are Gram negative, non-motile, usually capsulated rods. Culture Klebsiellae are aerobes and facultative anaerobes. Blood agar: Klebsiellae produce large grey white usually mucoid
colonies. MacConkey agar and CLED medium: Most klebsiellae are lactose-
fermenting, producing mucoid pink colonies on MacConkey agar and yellow mucoid colonies on CLED medium
K. rhinoscleromatis is non-lactose fermenting. Biochemical tests Klebsiellae are indole negative, ornithine decarboxylase negative and do
not produce H2S.
Klebsiella on Macconkey medium show large mucoid pink lactose fermenting colony
Klebsiella on CLED medium show yellow lactose fermenting colony
Enterobacter
LDCADHODCUreaseYellowpigment
E. cloacae-++ V-E. aerogenes+-+- -
E. gergoviae+-++ -E. sakazakii-++- +E. taylorae-+- + -
-species: habitat: soil, water, dairy products-normal flora of the gut of animals & humans-motile, ODC & ONPG (+)
Edwardsiella
Edwardsiellatarda (human pathogen –
bacteremia and wound infection)hoshinae (snakes, birds and
water)ictaluri (enteric septicemia in
fish)
Serratiaopportunistic pathogensDNAse, lipase, gelatinase
○S. marcescens○S. liquefaciens○S. rubidaea○S. oderifera
Proteus
Tow important species , P. mirabilis and P. vulgaris
Morphology Proteus is actively motile with peritricous
flagella , non capsulate, Gram negative pleomorphic rods.
Rapid urease producers Swarming, burned chocolate odor
Proteus with peritricous flagella
PathogenicityP. mirabilis causes: 1- Urinary infections. in the elderly and young males and often following catheterization or cystoscopy..2- Abdominal and wound infections 3- secondary invader of ulcers, burns and damaged tissues. 4- Septicaemia 5- Meningitis and Chest infections.
Cultureaerobically, most Proteus cultures have a characteristic ‘fishy’ Odour and Swarming on the medium
MacConkey, CLED, XLD media: non-lactose fermenting colonies after overnight incubation at 35–37 ºCSwarming is prevented on MacConkey agar and XLD agar because these media contain bile salts.Swarming is inhibited on CLED agar because it
is electrolyte deficientBiochemical testsDo not ferment lactose. Rapidly hydrolyze urea (within 4 hours), early screening test in differentiating enteric pathogens, e.g. salmonellae and shigellae from Proteus.Phenylalanine deaminase (PDA), positive.Indole negative (P. vulgaris is indole positive).
Proteus P. mirabilis P. vulgaris
Indole-+ODC+-
Fermentation Maltose - + Xylose + + Salicin - +
ChloramphenicolSR
Proteus P. mirabilis P. vulgaris
Indole……….…… Maltose……….……Xylose..…….……Salicin ..…….……
Chloramphenicol..…………
Morganella Formerl known as Proteus M. morganii – only specie UTI’s and wound infections
Providencia Providencia ( 4 species – P. alcalifaciens,
P. Rustigianii, P. rettgeri, P. stuartii)P. rettgeri P. stuartii
Urease + - Citrate + +
Yersinia 11 species
Y. pestis (plague) – bipolar staining (wayson) Agent of bubonic plague, pneumonic and septicemic plagues
○ Bubonic – bite of infected flea○ Pneumonic○ Prefered growth at 25 deg C
Y. enterocolitica (acute enteritis – appendictis like)○ Pig, cats and dogs ○ Cold enrichment○ Motile at RT
Y. pseudotuberculosis○ Pathogen in animals (turkey, geese, doves, farm and
domestic animals)
YERSINIA
Safety pin appearance
Yersinia pestis
Revision Question 1- Characteristic of enterobacterceae all of the following
except : a- Gram negative rod b- Facultative anaerobic c- Ferment glucose d- Oxidase positive 2-Sworming is special characteristic of: a. Pseudomonades b- Proteus c- E. coli d- Klebsiella 3- Mucoid colony is special characteristic of: a. Pseudomonades b- Proteus c- E. coli d- Klebsiella
4- Bacteria which give green metallic sheen on EMB medium is:
a. Pseudomonades b- Proteus c- E. coli d- Klebsiella 5- Polysaccharide capsule present on which of the following
bacteria: a. Pseudomonades b- Proteus c- Shigella d- Klebsiella 6- Which of the following bacteria is urease positive : a. Pseudomonades b- Proteus c- E. coli d- Klebsiella 7- Which of the following bacteria is lactose fermenter: a. Pseudomonades b- Proteus c- E. coli
When we inoculate members of enterobacterceae on MacConkey agar, mention which organism grow producing lactose fermentor colony and which grow producing lactose fermentor colony
klebsiella and e.coli
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