Investigation of Genetic Similarities of the Isolated Pseudomonas Aeruginosa from Hospitals and their Surrounding Areas by Rep-PCR Method

Background: Pseudomonas (P.) aeruginosa is one of the most common causes of nosocomial infections. The aim of this study was to explore the antibiotic resistance pattern and genetic association of P. aeruginosa strains isolated from Kermanshah hospitals and their surrounding areas. Methods: The samples included both soils from around three hospitals and clinical specimens of the same hospitals. Once the samples were enriched and the colonies were isolated, the positive samples of this bacterium were confirmed using biochemical tests. Then, antibiotic susceptibility testing (AST) was performed using the disc diffusion method (DDM). Finally, the phylogenetic relationship between the isolates was examined using the repPCR technique. In all experiments, the standard strain (ATCC:27853) was used as a positive control. Results: Thirteen and 36 (27 urines, 7 burns and 2 septa) isolates were detected from environmental and clinical samples, respectively. Results showed that clinical strains had the highest resistance to ceftriaxone (94.44%) and the lowest resistance to imipenem (72.2%). On the other hand, environmental strains around the hospital showed the highest resistance to amikacin (92.3%) and the lowest resistance to imipenem (53.84%). Overall, 46 patterns were observed in the strains. The dendrogram indicated that a number of clinical and environmental strains had close genetic similarities. Strains 35C and 9E (clinical strain 35 and environmental strain 9) were 100% similar, which could imply that they originated from a clonal strain. Also, strains 3C, 26C, and 13E were 100% similar. Conclusion: Despite the differences in antibiotic resistance pattern between hospital and environmental isolates, there were genetic similarities between the two isolates.