Minimum requirements for definitive identification of Pseudomonas aeruginosa

This post was most recently updated on February 2nd, 2015

If a Microbiologist isolated a pathogenic bacteria in the laboratory and suspected that this pathogenic bacteria is a Pseudomonas aeruginosa based on its Gram staining characteristics, colony morphology and biochemical tests.

Before reporting the isolate as Pseudomonas aeruginosa, the isolate must have fulfilled the following minimum requirements.

1. Gram staining: Gram negative rod
2. Oxidase positive
3. Typical smell (fruity grape-like odor or corn tortilla)
4. Recognizable colony morphology
   1. On blood agar or chocolate agar appear as give large colonies with metallic sheen, mucoid, rough, or pigmented (pyocyanin) and often Beta Hemolytic
   2. On MacConkey Agar colonies appear as lactose-negative with green pigmentation, or metallic sheen