Identification of Pseudomonas aeruginosa common among microorganisms isolated from ear infections in Karbala Governorate

Abstract

Abstract

Pseudomonas aeruginosa is one of pathogenic opportunistic microbes that can infect almost every tissues in the body due to its possession of a variety of virulent properties that contribute significantly to pathogenicity. To detect the prevalence of P 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 isolates (30.93%) were P. aeruginosa, with other 67 isolates (69.07%) belonging to various microbial genera. P. 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. P. aeruginosa was also investigated for some virulence factors, the results indicated that all isolates )100% (produced hemolysin, whereas 23 isolates (76.66%) were positive for Protease qualitative assay, and 24 of the isolates (80%) produced Pyocyanin pigment.