Genotypic characterisation and antimicrobial resistance of Pseudomonas aeruginosa strains isolated from patients of different hospitals and medical centres from Poland

Abstract

Background Pseudomonas aeruginosa is a Gram-negative bacillus responsible for infections in immunocompromised patients and is one of the most common causes of nosocomial infections particularly in intensive care and burn units. We aimed to investigate the population structure of P. aeruginosa strains isolated from patients at different hospital wards. Methods We analysed a possible presence of P. aeruginosa epidemic or endemic strains in hospitals of the selected region. A genotyping analysis was performed for 202 P. aeruginosa isolates collected from patients of eleven hospitals in north-western Poland. Collections of P. aeruginosa were genotyped using pulsed-field gel electrophoresis (PFGE). Phenotypic screening for antibiotic susceptibility was performed for the common antimicrobial agents. Results All P. aeruginosa isolates were distributed among 116 different pulsotype groups. We identified 30 groups of clonally related strains, each containing from 2 to 17 isolates. Typed the obtained 13 unique patterns, designated as A, D, J, K, M, N, Ó, P, T, X, AC, AD, and AH. The two largest clusters, D and E, contained 17 and 13 isolates, respectively. Strains of those groups were continuously isolated from patients at intensive care units and burn units, indicating transmission of those strains. Conclusions In this study, we demonstrate the clonal relatedness of P. aeruginosa strains and their constant exchange in hospitals over a period of 15 months. The obtained results indicate a predominantly non-clonal structure of P. aeruginosa .