GRAM NEGATIVE BACILLI

Morphology Cultural Characteristic Biochemical test Diseases

Escherichia coli

Klebsiella pneumonia

Salmonellae

Shigella

Enterobacter aerogenes

Proteus

and plump motile rods

non-motile gram (-) capsulated rods

Gram (-) aerobic rods; motile (peritrichous) except S. gallinarum and S. pullorum

Gram (-) slender, non encapsulated and non-motile

motile

motile gram (+)

-develops greenish metallic sheen (EMB)-produce pinkish colonies (MacConkey)-produce yellow colonies (XLD)

develop large mucoid colonies that exhibit + string test (EMB, MacConkey, XLD)

-organisms develop colorless colonies (EMB, MacConkey, and Salmonella and Shigella agar SSA)

-Colorless colonies (EMB, SSA, MacConkey)-pinkish to redish colonies (XLD)-green to blue green colonies (HEA)

pink colony (MacConkey)

swarm on BAP

TSI : A/AgIMViC : + + - -

TSI : A/AgIMViC : - - + +

TSI : K/A + H2SIMViC : - + - +

TSI – K/AIMViC – V + -

TSI : A/AgIMViC : - - + +

TSI: K/A + H2S

-UTI -neonatal meningitis -Bacteremia -pneumonia -nosocomial wound

-Severe enteritis -pneumonia -septicemia-bacteremia -meningitis

S. typhi – typhoid fever, meningitis, osteomyelitisS. paratyphi A & B – paratyphoid feverS. paratyphi C – septicemiaSalmonella enteritidis – gastroenteritis

Bacillary dysentery (abdominal cramps, diarrhea and fever)

-UTI - wound - septicemia

Typhus fever

Edwardsiella tarda

Arizona hinshawii

Citrobacter freundii

Serratia marescens

Morganella morgani (proteus morgani)

Yersinia pestis:

Yersinia enterocolitica

VibrionaceaeVibrio cholera (comma bacillus)

pleomorphic rods

motile

motile, late lactose fermenter

similar to E. coli

motile

plaque bacillusGram - , non motile

Motile

Curved/comma shaped rod, gram (–) rods, exhibits darting motility, “fish in the stream”.

Blue color (sodium malonate medium)

production of DNAse

similar to Proteus

Reddish pink colony (Deoxycholate agar), stalactite streamers (broth cultures).

Bull’s eye colony

yellow colonies with opaque centers and transparent periphery thiosulfate citrate bile salts

IMVIC:P. vulgaris + + - VP. mirabilis - + V VSerological test: Weil Felix

TSI: K/Ag + H2SIMVIC: + + - -

TSI: A/A + H2S

TSI: K/AIMVIC: - - + +

TSI: K/AIMVIC: - + - -

TSI: A/A

Nitroso indo test (Cholera red test)TSI: A/A

Diarrhea, wound, bacteremia

C. freundii: UTI, pneumonia, endocarditis, abscessC. diversus: neonatal meningitis

nosocomial (pneumonia, bacteremia, UTI)

plague

Cholera

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Vibrio parahaemolyticus

Pseudomonas aeroginosa

Pseudomonas mallei (Glander’s bacillus)

Pseudomonas pseudomallei (whitmore’s bacillus)

Pseudomonas maltophilia

Alcaligenes faecalis

Flavobacterium meningosepticum

Haemophilus influenzae

Gram (-) rods, non encapsulated

Non-motile, non encapsulated

non motile

motile with lopotrichous flagella,

motile with peritrichous flagella, short gram (-) rods.

non-motile gram (-) aerobic bacilli

Gram-negative, coccobacillary, facultatively anaerobic bacterium

sucrose (TCBS), Tellurite Taurocholate gelatin Agar (TTGA).

Green (TCBS)

Produce large flat colonies with round glass appearance (BAP). Sweet aromatic; fruity or grape like odor.

Wrinkled colony (ashdown medium)

produces yellow tan pigments develops an ammoniacal odor (BAP).

Colorless (Mac Conkey agar)

produce yellow pigment (BAP & CAP)

Blood agar growth - appear as convex, smooth,

catalase and oxidase tests - positive

Gastro enteritis (Sea food)

Wound, burn, cystic fibrosis, UTI.

Glander’s disease (Farcy)

Meliordosis or Glander’s like

meningitis -bacteremia

bacteremia, pneumonia, epiglottitis and acute bacterial meningitis

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Bordetella pertusisgram (-) minute coccobacilli, encapsulated, non-motile

pale, grey or transparent colonies

pearl like (Bordet gengou)whooping cough

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