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