Enumeration, isolation, and identification of Pseudomonas aeruginosa

The samples were analyzed using a dilution method to achieve bacterial suspension concentration of 10⁻¹–10⁻³, then 1 ml of each concentration was inoculated in the petri dish containing 19 ml agar MacConkey and aerobically incubated at 37°C for 24 h. The colony number of P. aeruginosa were counted using a colony counter tool and then subcultured to fresh MacConkey agar plates, incubated at 37°C and further identified after 18–24 h. The colonies were verified using phenotypic identification and biochemical tests, i.e., oxidase test, triple sugar iron test, Indole test, motile test, carbohydrate fermentation (a serial fermentation test of glucose, lactose, sucrose, maltose, and mannitol), citrate test, Methyl Red, and Voges–Proskauer test. The identification results were then compared to the P. aeruginosa ATCC 27853 as bacterial standard.