Prevalence of the Genes Associated with Biofilm and Toxins Synthesis amongst the Pseudomonas aeruginosa Clinical Strains.

Tomasz Bogiel,Dagmara Depka,Mateusz Rzepka,Joanna Kwiecińska-Piróg,Eugenia Gospodarek-Komkowska

doi:10.3390/antibiotics10030241

Tomasz Bogiel, Dagmara Depka + Show 3 more

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https://doi.org/10.3390/antibiotics10030241

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Abstract

Pseudomonas aeruginosa is one of the most commonly isolated bacteria from clinical specimens, with an increasing isolation frequency in nosocomial outbreaks. The hypothesis tested was whether carbapenem-resistant P. aeruginosa strains display an altered carriage of the virulence factor genes, depending on the type of carbapenem resistance. The aim of the study was to investigate, by PCR, the frequency of 10 chosen virulence factors genes (phzM, phzS, exoT, exoY, exoU, toxA, exoS, algD, pilA and pilB) and the genotype distribution in 107 non-duplicated carbapenem-resistant P. aeruginosa isolates. P. aeruginosa genes involved in phenazine dyes and exoenzyme T synthesis were noted with the highest frequency (100%). Fimbriae-encoding genes were detected with the lowest incidence: 15.9% and 4.7% for pilin A and B, respectively. The differences observed between the exoS gene prevalence amongst the carbapenemase-positive and the carbapenemase-negative strains and the pilA gene prevalence amongst the strains of different origins were statistically significant. Virulence genes’ prevalence and the genotype distribution vary amongst P. aeruginosa strains resistant to carbapenems, especially in terms of their carbapenemase synthesis ability and the strain origin.

Highlights

Pseudomonas aeruginosa is a ubiquitous Gram-negative non-fermenting rod, a typical bacterial opportunistic pathogen often found in a hospital environment
Little information on the virulence gene prevalence and genotype distribution amongst the carbapenem-resistant P. aeruginosa (CRPA) strains can be found in the relevant literature [10,11]
Three of the strains studied in the present work carried both of the mentioned genes. These results indicate that for the evaluated strains group, the potential for alginate synthesis, observed at least on a molecular level, might be one of the major determinants involved in biofilm formation

Summary

Introduction

Pseudomonas aeruginosa is a ubiquitous Gram-negative non-fermenting rod, a typical bacterial opportunistic pathogen often found in a hospital environment. P. aeruginosa rods are one of the most often isolated bacteria from clinical specimens. Their increasing resistance to carbapenems and their role in nosocomial outbreaks of different localizations are underlined by their involvement in severe respiratory and urinary tract infections, as well as skin and soft tissue infections or bacteremia [1]. P. aeruginosa rods are intrinsically resistant to numerous antimicrobials and acquire antibiotic resistance mechanisms to the majority of antibiotic groups, including carbapenems. These beta-lactam representatives (e.g., imipenem and meropenem) are often the last-resort antibiotics. P. aeruginosa resistance to carbapenems may result from a loss of OprD protein porins responsible for carbapenem transport into bacterial cells, overexpression of efflux pumps that actively pump out antimicrobials outside the cell or some other carbapenem-hydrolyzing enzymes

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