Isolation and Identification of Pseudomonas aeruginosa common among microorganisms causing ear infections in Karbala Governorate

الملخص

To detect the prevalence of Pseudomonas aeruginosa from different stages of ear infections and to study some of the virulence factors possessed by this bacterium, 110 swabs from ear infections were collected and cultured on blood agar, MacConkey agar and cetrimide agar plates media. The plates were incubated for 24 to 48 hours at 37°C, and growth was determined using these media. The microbial isolates were differentiated using a variety of biochemical techniques. The common isolates identified using standard bacteriological methods namely morphology, colony characteristics and biochemical tests. The results showed that 30.93% (30/97) were Pseudomonas aeruginosa, with other 69.07% (67/97) isolates belonging to various microbial genera. Pseudomonas aeruginosa was Gram-negative, showed hemolysis upon blood agar, and were motile. Biochemical assays revealed that each isolate were positive for catalase, oxidase, citrate, and indole. The results were confirmed using VITEK 2 system and the polymerase chain reaction (PCR) to investigate the 16srRNA gene. PCR results revealed that 100% of the isolates possessed this gene with a size of 956 base pairs. Pseudomonas aeruginosa was also investigated for some virulence factors, the results indicated that all isolates 100% produced hemolysin, whereas 76.66% (23/30) were positive for protease qualitative assay, 80% (24/30) of the isolates produced pyocyanin pigment.