Gram Negative Bacteria - JU Medicine · lactose fermenter o Swarming motility ( flagellated ) ... Pseudomonas aeruginosa Most isolated q specie non lactose fermentas r Very special

Gram Negative Bacteria

selective forisolation Macconkey Enterobacteriaceae Gram0

Agar differentialis

lactose non lactosefermentas fermentas

(E.coli)1. Escherichia coli

Mostcommon typelactose tNo specific character DrycolonyRods

2. Klebsiella

• Large mucoid polysaccharide capsule .

weakor lateqlactose fermentas

Give Mucoid colonybecause it is encapsulated

3. EnterobacterNo specificcharacterSimilar to Ecoli

4. Citrobacter

o Gram negative rods , nonlactose fermenter

o Swarming motility ( flagellated )

o Prevent swarming by culturingit on CLED or Macconkey media

Proteus

e

pedal

spread inthe Media

used More 4than Macc

I l I d

identified by :•Gram negative rods•odor : grape-like smell.•Oxidase positive.•Produce different pigments colors:

• Pyocyanine (blue-green)• Pyoverdin (fluorescent yellow –greenish

pigment).• Pyorubrin (red).• Pyomelanin (brown).

Pseudomonas aeruginosaMost isolated qspecie

non lactosefermentas

r Veryspecialcharacter

Gives violet color

IThe color depend on the type ofPigment produced

Pseudomonas aeruginosa on mueller hintion agar

gm 1 Pr

TheTediatakesthecolor of the pigment