GENERAL CHARACTERISTICS

•Facultative anaerobe or aerobe

•Motile or non-motile
•Some are with pili or fimbriae
•Grows well on Mc Conkey agar
•Ferments rather than oxidize
glucose and often with gas
production
•Catalase negative and Oxidase
positive
1. EMB
2. Mac Conkey Agar
3. GN Broth
4. Hektoen Enteric Agar ( HEA )
5. Salmonella Shigella Agar ( SSA )
6. Selenite Broth
7. Tetrathionate Broth
8. CIN ( Cesulodin Irgasan Novbiocin )
9. XLD ( Xylose Lysine Deoxycholate )
 Media : Triple Sugar Iron ( TSI )
( With Phenol Red and Ferrous Sulfate )
RESULT :
a) Non-Fermenter (NF)
Alkaline slant and butt, no sugar was fermented
Report as K/K
b) Non-Lactose Fermenter (NLF)
Alkaline slant and Acid butt , only glucose was fermented
Report as K/A
c) Lactose Fermenter (LF)
Acid slant and Butt, glucose was fermented , lactose and/or
sucrose was fermented
Report as A/A
 NLF
( Non-Lactose LF ( Lactose Fermenter )
Fermenter )
• Enterobacter
• • Escherichia
Edwardsiella • Klebsiella
• Hafnia
• Morganella
• Proteus LLF
( Late Lactose Fermenter )
• Providencia
• Salmonella
• Citrobacter
• Shigella
•Serratia
• Yersinia
•Arizona
 • Result:
• Based on the ability • Media : MRVP broth or
(+) = distinct red color
of organism to Clark Lubbs Broth
(-) = no color change
produce indole from Indicator : Methyl Red
Tryptophan
• Media :
Tryptophan broth
• Media: MRVP broth or • Result:
Reagent: KOVAC’s
Clark Lubbs Broth (+) = pink to red color
or Ehrlich’s Reagent
Reagent: Alpha naphthol (-) = no color change
• Result: and KOH
(+) = red ring
(-) = no color
development
• Media: Simmon Citrate Agar • Result:
Indicator: Bromthymol blue (+) = intense blue color
(-) = green color
 INDOLE TEST METHYL RED TEST

VOGUES-PROSKAUER TEST CITRATE UTILIZATION

 LACTOSE FERMENTERS

Indole Methyl VP Test Citrate

Red Test

E. Coli + + - -
Klebsiella - - + +
Enterobacter - - + +
Media: Christensen’s Urea Agar Media: TSI, LIA, SIM, HEA
Result (+) = pink/magenta Result: Production of Black
(-) = no color change color
• uses lysine, tryptophan or phenylalanine
• (+) Proteus ; Providencia and Morganella
PHENYLALANINE
DEAMINASE TEST
(PAD)
Media : Phenylalanine agar
or Tryptophan agar
Reagent: 10% Ferric
Chloride
Result:
(+) = green color on slant
( Phenylalanine agar )
(+) = brown
( tryptophan agar )
(+) Shigella and Klebsiella (+) Citrobacter
(+) Yersinia enterocolitica (22 degC) (-) Salmonella except: S.
arizonae
Result: (+) yellow
(-) no color change

Left : Motile
Right: Non-motile
 LYSINE DECARBOXYLASE TEST
• Detects ability of the
organism to remove Media : Lysine Iron Agar
the carboxyl group Result: (+) = purple color ( in butt )
from a specific amino (-) = yellow ( in butt )
acid
• Lysine, ornithine
and arginine usually
tested
 Serotypes of E. coli associated
with Diarrhea and Gastroenteritis
• ETEC ( Enterotoxigenic E. coli )
• Pink to red colonies • EIEC ( Enteroinvasive E. coli )
on Mac Conkey agar • EPEC ( Enteropathogenic E. coli )
• Greenish metallic • EHEC ( Enterohemorrhagic E. coli )/
sheen on EMB VTEC ( Vero Toxic E. coli )
• TSI : Acid butt and • EAEC ( Enteroaggregative E. coli )
slant with Gas
• ONPG (+)
• may cause UTI, Anaerogenic E. coli or Inactive E. coli
septicemia , Meningitis • negative gas production
in infants • lactose negative
• may cause diarrhea • non-motile
and gastroenteritis • previously called ALKALESCENS
DISPAR
 • causes bacillary dysentery
• Resembles E. coli but are lactose (-)
• non-motile
• Clear colonies on Mac Conkey
• TSI: K/A no gas
Subgroup Specie Lactose Mannitol ODC ONPG

A Shigella - - - -
dysenteriae/ Shiga
Bacillus
B Shigella - + - -
flexneri/Strong’s
Bacillus
C Shigella boydii - + - -

D Shigella sonnei/ - + + +
Duval’s Bacillus
 • resembles
Salmonella but
are ONPG (+) and
LDC (-) • identified as a source of GI
• C. freundii and infection
C. diversus may • identified by the abundance
cause UTI and of H2S on TSI
RTI • Biochemically resembles E.
• slow lactose coli except that it is
fermenter and H2S (=) and lactose (-),
citrate positive • IMViC Reaction is ( + + - - )
KLEBSIELLA- ENTEROBACTER-SERRATIA-HAFNIA
GROUP

1. Klebsiella pneumoniae
• a.k.a Friedlander’s Bacillus
• Mucoid colonies (+) String Test
• short, NM • Pink mucoid colonies on Mac Conkey
• ODC (-) • TSI : A/A + gas
• with large polysaccharide • (+) Neufeld Quellung
Capsule • Can cause severe pneumonia, lung
abscess
• Neonatal menigitis and wound
infections

Other Klebsiella spp.

2. Klebsiella oxytoca
3. Klebsiella ozonae
4. Klebsiella rhinoscleromatis
KLEBSIELLA- ENTEROBACTER-SERRATIA-HAFNIA
GROUP

• opportunistic pathogens
Hafnia alvei
• (-) lactose, • clear colonies on Mac Conkey
sucrose, Dnase, Lipase & gelatinase (+)
sorbitol TSI : K/A
• (-) sorbitol &
raffinose
• Citrate (-) SERRATIA SPP.
• DNase and 1. Serratia marcescens
Lipase (-) 2. Serratia liquifaciens
3. Serratia rubidaea
4. Serratia odorifera
 KLEBSIELLA- ENTEROBACTER-SERRATIA-
HAFNIA GROUP
• normal flora of GIT; motile and ODC (+)
• TSI : A/A + gas
Urease Yellow Lactose LDC ADH ODC
Pigment Fermentation
Enterobacter - - + + - +
aerogenes
Enterobacter V - + - + +
cloacae
Enterobacter + - V + - +
gergoviae
Enterobacter - + + - + +
sakazakii
Enterobacter - - - - + +
taylorae
 Genus SALMONELLA
• Pathogenic ; motile ; NLF ; Produce H2S
• S. typhi does not form gas & produce only small amount
of H2S
• Clear Colonies on Mac Conkey
• Green colonies with black centers on HEA
• TSI: K/A + gas

Subgroup 1
1. Salmonella typhi/ Eberth’s Bacillus
2. Salmonella paratyphi
2.1 Salmonella paratyphi B / Salmonella scottmuelleri
2.2 Salmonella paratyphi C /Salmonella hirschfeldii
3. Salmonella cholerasuis
4. Salmonella gallinarum
Salmonella pullorum
 Genus SALMONELLA
1. Enterocolitis/gastroenteritis
( S. typhimurium , S. gallinarum , S. enteritidis )

2. Bacteremia ( S. cholerasuis )

3. Enteric Fever / Typhoid Fever

- maybe caused by S. typhi
- fecal-oral route
- (+) Rose spots on the skin, abdomen and chest

4. Paratyphoid fever ( S. paratyphi )

 PROTEUS- PROVIDENCIA –MORGANELLA
GROUP

PROTEUS
• rapid
urease
activity
• swarming
motility on
BAP
• TSI : K/A +
gas, H2S
• Clear
colonies on
Mac Conkey
PROTEUS- PROVIDENCIA –MORGANELLA
GROUP

Proteus mirabilis
• Indole negative
• Susceptible to ampicillin, cephalosporin &
chloramphenicol

Proteus vulgaris
• Indole positive
• Resistant to ampicillin, cephalosporin and
chloramphenicol
 PROTEUS- PROVIDENCIA –MORGANELLA
GROUP

PROVIDENCIA MORGANELLA
• normal intestinal
flora
• all cause UTI Morganella morganii
• lactose & H2S • lactose, citrate, H2S and LDC
negative negative
• Deaminase & • urease and deaminase positive
Citrate positive • UTI’s and RTI’s
• Do not Swarm on
BAP
Povidencia rettgeri
Providencia stuartii
• exhibits bipolar staining (safety pin appearance on Wayson stain)
• small coccobacilli, with small pinpoint colonies on Mac Conkey
• weak acid production
• NM at 37 degC
• all are motile at room temperature (25-30 degC) except Y. pestis

Yersinia pestis
• agent of PLAGUE

Yersinis
enterocolitica
• most common
Yersinia isolated
from human
• causes
enterocolitis
swollen lymph glands (buboes) caused
by plague bacteria in bubonic plague
 Plague patient
displaying a swollen
axillary lymph node

Gangrene is one of
the manifestations of
plague, and is the
origin of the term
"Black Death" given
to plague throughout
the ages 
 IDENTIFICATION OF ENTEROBACTERIACEAE

SPECIES Indole Methyl VP Citrate H2S Urea

Red
Escherichia coli + + - - - -
Shigella serogroups V + - - - -
A,B,C
Salmonella typhi - + - - + -
Salmonella paratyphi A - + - - - -
Citrobacter freundii - + - + V V
Citrobacter diversus + + - + - V
Edwardsiella tarda + + - - + -
Klebsiella pneumoniae - - + + - +
Klebsiella oxytoca + V + + - +
 IDENTIFICATION OF ENTEROBACTERIACEAE

SPECIES Indole Methyl VP Citrate H2S Urea

Red
Enterobacter aerogenes - - + + - -
Hafnia alvei - v v - - -
Serratia marcescens - v + + - v
Proteus mirabilis - + - v + +
Proteus vulgaris + + - v + +
Morganella morganii + + - - - +
Yersinia pestis - v - - - -
Yersinia enterocolitica - + - - - v
 IDENTIFICATION OF ENTEROBACTERIACEAE

SPECIES PDA LDC ODC MOTILITY

Escherichia coli - + v +
Shigella serogroups A,B,C - - - -
Salmonella typhi - + - +
Salmonella paratyphi A - - + +
Citrobacter freundii - - v +
Citrobacter diversus - - + +
Edwardsiella tarda - + + +
Klebsiella pneumoniae - + - -
Klebsiella oxytoca - + - -
 IDENTIFICATION OF ENTEROBACTERIACEAE

SPECIES PDA LDC ODC Motility

Enterobacter aerogenes - + + +
Hafnia alvei - V + -
Serratia marcescens - + + +
Proteus mirabilis + - + +
Proteus vulgaris + - - +
Morganella morganii + - + +
Yersinia pestis - - - -
Yersinia enterocolitica - - + -