Other Enterobacteriaceae

8/8/2019 Other Enterobacteriaceae

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Other Enterobacteriaceae


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Tribe Genus

I Escherichiae Escherichia,Shigella

II Edwardsielleae Edwardsiella

III Salmonelleae Salmonella

IV Citrobactereae Citrobacter

V Klebsiellaea Klebsiella,

Enterobacter, Serratia

VIProteeae Proteus, Morganella,Providencia

VII Yersineae Yersinia

VIII Erwineae Erwina


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Tribe Proteeae

Proteus, Providencia and Morganellaspp.


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Morphology

GNR

Size- 1-3 m X 0.6 m

Actively motile by peritrichous flagella

Note:

Hauch Motile (Flagellar antigen)

Ohne Hauch Nonmotile (onlysomatic antigen)


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Virulencefactors

Production of urease

Siderophores are essential for bacteria to acquireiron


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EPIDEMIOLOGY

Habitat

Found in the faeces of animals and humans as wellas in associated materials such as decomposingmeat and sewage


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HUMAN INFECTIONS

Urinary tract infection

This bacterium has the ability to produce highlevels of urease, which hydrolyzes urea toammonia and thus makes the urine morealkaline.

If left untreated, the increased alkalinity can leadto the formation of crystals of struvite, calciumcarbonate, and/or apatite.


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LABORATORY DIAGNOSIS Nutrient, blood and MacConkeys agar

Fishy or seminal odour

Test P. mirabilis P. vulgaris Morganellamorganii

Providenciarettgeri

Providenciaspp.

Indole - + + + +

Citrate + - - + +

Urease + + + + -

Ornithinedecarboxylase

+ - + - -

H2S + + - - -


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Proteus spp. exhibits Swarming

Swarming inhibted by

Increase conc of agar(6%)Add chloral hydrateSodium azideBoric acidBile salt


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RESISTANCE TO ANTIMICROBIALS

Proteus bacilli are usually resistant to commonly usedantibiotics, butP. mirabilis is generally very susceptible to

antibiotics

Most isolates of Proteeae are susceptible toaminoglycosides

Proteeae are usually intrinsically resistant to the

polymyxins and nitrofurantoins Resistance to trimethoprim and fluoroquinolones are

increasing


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ENTEROBACTER SPECIES

Enterobacter spp. differ from Klebsiella spp. in

being motile There are 15 species in the genus:

E. cloacae,

E. aerogenes,

E. agglomerans (nowPantoea agglomerans)


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ENTEROBACTER SPECIES

They ferment glucose with production of acid

and gas and are Methyl red negative andVoges-Proskauerpositive.

Enterobacter (Pantoea) agglomerans andE.

sakazakii produce a yellow diffusible pigmentat20 Con agar


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PATHOGENICITY

Enterobacter spp. are importantnosocomial

and opportunistic pathogens.


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EPIDEMIOLOGY

Normal Habitat

Enterobacter spp. are found in soil and water butE. cloacaeandE. aerogenes can be a minoritycomponent of the intestinal flora of human andother animals


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ANTIMICROBIAL SUSCEPTIBILITY

Resistant to cephradine, cefuroxime and

amoxycillin, but most isolates remain sensitiveto cefotaxime, ceftazidime, cefpirome,imipenem, gentamicin and ciprofloxacin


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SERRATIA SPECIES

The red pigment produced byS. marcescens is

water insoluble,and is called prodigiosin Responsible for the appearance of blood onfoodstuffs throughout history

Its presence in sputum has also led to a

misdiagnosis of bronchiectasis or even bronchialcarcinoma


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Biochemical reactions

Serratia spp. are indole negative, produce

lecithinase and lipase and are more likely to begelatinase and DNAase positive

Voges-Proskauer positive


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Species

S. marcescens,S. liquefaciens and S. rubidaea

are most often associated with human infection


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DESCRIPTION

Straight rods

Motile by means of peritrichous flagella Fishy-urinary odour


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PATHOGENICITY

Class 3 fimbriae - virulence determinants

Ability to survive in disinfectant solution, togrow at relatively low temperatures and toadhere to plastics can provide a reservoir forinfection

Pore-forming haemolysin, allows the bacteriumto acquire haemoglobin and haem using anextracellular scavenger protein


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EPIDEMIOLOGY AND INFECTIONS

Normal Habitat

S

erratia spp. are widely distributed in theenvironment and can be found in the rodent gutand occasionally in the human intestinal tract.

Colonize the premature neonates intestinal tract -red diaper syndrome

Serratia spp. are nosocomial and opportunisticpathogens


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CLINICAL FEATURES

Serratia spp. can cause urinary tract infection,

pneumonia, meningitis (rarely),endophthalmitis, bacteraemia and woundinfections


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Antimicrobial Susceptibility

As forEnterobacter spp.,Serratia spp. are

generally resistantto cefuroxime, cephradineand amoxycillin but sensitive to ceftazidime,

imipenem, cefpirome and ciprofloxacin


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THANKS

Documents

Other Enterobacteriaceae