enterobacteriaceae

SERRATIA

MORPHOLOGY

entire margins umbonate elevation. Gram negative motile bacillus shape mucoid colonies

CULTURE facultative anaerobe grown on nutrient agar 48 h at 25˚C. Optimum growth: pH 9 and at temperatures from 20-37 C.

SEROLOGY

difficult to treat because of resistance to a variety of antibiotics P-Lactam resistance Aminoglycoside resistance

BIOCHEMICAL TEST

oxidase test (positive) negative for methyl red test. Reduce nitrate Indole negative Simmon's citrate positive

ESCHERICHIA

a) Morphology

Colony: size: small shape: circular margin: smooth. elevation: raised

Gram Stain: negative rod shaped.

b) Culture

Mac conkey agar : pink pigmentation (lactose fermenter)

c) Biochemical test Indole(+) Methyl red test(+) Catalase(+)

d) Serology test

O antigen: part of lipopolysaccharide layer; H: flagellin; K antigen: capsule

ENTEROBACTER

1)morphology

-gram negative rod -capsulated -motile -Straight rod shape. -0.6-1.0 micrometers wide X 1.2-3.0 micrometers long.

2)Culture

-Facultative anaerobe. -Best results are obtained when Enterobacter cultures are incubated at 30°C. At 37°C.

3)Biochemical test

-Indole negative. -Lysine negative (except E. gergoviae). -Voges-Proskauer positive (mostly). Simmons citrate positive (mostly).

4)Serology test

extremely strong cross-reactivity with Shigella dysenteriae.

PROTEUS :

MORPHOLOGY • shape : rod • Gram Negative • motile

CULTURE • Facultative anaerobes • Do not form endospores • Exhibit swarming behavior - form concentric rings as they spread across the surface of agar plates.

SEROLOGY • Treatment with ampicillin and aminoglycosides

BIOCHEMICAL TESTS • Oxidase negative • Catalase positive • Nitrate positive • Urease positive • Phenylalanine deaminase positive

PROVIDENCIA

MORPHOLOGY : • Gram Negative • Motile • Non-sporeforming

CULTURE : • Aerobic or facultative anaerobic

BIOCHEMICAL TESTS : • Citrate utilization - Positive • d-Mannose fermentation - Positive • Gelatin liquefaction (22°C) -Negative • H2S production (TSI) - Negative • Lipase (corn oil) - Negative • Ornithine decarboxylase - Negative

• Swarming - Negative

SEROLOGY : • Sensitive to ampicillin

MORGANELLA

MORPHOLOGY

Straight rods, 0.6-0.7 um in diameter and 1.0-1.7 um in Motile by means of peritrichous flagella large,gray, moist colonies

CULTURE

grow on nutrient agar,MacConkey agar, trypticase soy agar. Facultatively anaerobic Gram-negative

SEROLOGY

The 0 antigens were used for grouping the H antigens were used for further subclassification.

BIOCHEMICAL TEST

catalase :+ve gelatinase : -ve oxidase : -ve VP : -ve indole : +ve urease :+ve

CITROBACTER

Morphology

Belong to gammaproteobacteria Gram negative Non-spore forming Rod-shaped bacteria Mostly surrounded by flagella Motile Facultative anaerobes Culture

Most will grow in wide temperature range in ordinary culture media including nutrient agar and blood agar. On BA, enterobacteria produce large, shiny, grey colonies that may be haemolytic. A coliform & fecal coliform

Biochemical test

Indole test: posite. Ability to convert tryptophan to indole. ferment lactose, and use malonate.

Serology test

Some produce Vi (virulence) antigen

K.pneumoniae

morphology

- gram ngtve bact -non motile -slimy grayish white colonies on NA/muccoid appearance -small size ( 1-2 um) coccobacilli capsulated -arranged in pairs n cluster

culture

-facultative anaerobes -growth on NA - produce distinctive yeasty odor serology test - prodce nzyme (carbapenemase) makes it ressintant to drug carbapenem -inhibit growth of similar related strains bact by prodcng proteinaceous toxins

biochemical test -gram stain (-ve) -simmon citrate agar (+ve)

-indole(-ve) -carbohydrates fermentation(