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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