Pseudomonas aeruginosa, a widely distributed bacterium in the environment, is commonly found in soils, natural water sources, lakes, and rivers. While its presence is infrequent in drinking water, its detection is crucial in specific settings, particularly healthcare facilities, where it can pose a risk of infection. Although regular consumption of drinking water is not a typical source of P. aeruginosa infection for the general population, control measures are essential to limit the formation of biofilms and reduce the proliferation of these microorganisms.
Detection Method: ISO 16266:2006
The sample is filtered according to the specifications outlined in ISO 8199.
Place the membrane post-filtration in Pseudomonas CN Agar.
Incubate at 36 ºC ± 2 ºC for 44 ± 4 hours.
Examine growth after 22 hours and at the end of incubation.
Reading under Natural Light:
a) Blue/green colonies are counted as Pseudomonas aeruginosa.
b) Red/brown colonies are considered presumptive, and confirmatory tests are required.
After subculture in Nutrient Agar, perform the following tests:
Oxidase reaction (+)
Inoculate on Acetamide broth (+)
Inoculate on King B Medium (+)
Reading under UV Light:
Fluorescent colonies not producing pyocyanin are considered presumptive Pseudomonas aeruginosa.
Confirmation (UV Light):
After subculture in Nutrient Agar, perform inoculation on:
Acetamide broth (+)
The ISO 16266:2006 procedure provides a comprehensive method for the detection and count of Pseudomonas aeruginosa. By following these meticulous steps, professionals can ensure accurate identification, enabling effective control measures to minimize the risk of infection in various environments. The integration of natural and UV light readings enhances the specificity of the detection process, contributing to the overall safety and quality of water systems.