Unravelling the Features of Success of VIM-Producing ST111 and ST235 Pseudomonas aeruginosa in a Greek Hospital.

Costas C Papagiannitsis,Jaroslav Hrabak,Aggeliki Verra,Vasiliki Galani,Ibrahim Bitar,Stelios Xitsas,Efthymia Petinaki

doi:10.3390/microorganisms8121884

Abstract

The objective of this study was to analyze the characteristics that contribute to the successful dissemination of VIM-producing Pseudomonas aeruginosa (P. aeruginosa), belonging to ST111 and ST235, in a Greek hospital. A total of 120 non-repetitive P. aeruginosa, which had meropenem minimal inhibitory concentrations (MICs) greater than 2 mg/L, were studied. VIM-encoding genes were amplified and sequenced within their integrons. Isolates were typed by multilocus sequence typing (MLST). Six VIM-producers, representative of different integron structures and sequence types (STs), were completely sequenced using Illumina platform. Sixty-one P. aeruginosa were confirmed to produce VIM-type carbapenemases. ST111 dominated (n = 34) among VIM-producers, while 15 VIM-producers belonged to ST235. The blaVIM-like genes were located in three integron types, including In59, In595 and In1760, which were integrated into P. aeruginosa chromosomes. Whole genome sequencing (WGS) data demonstrated that ST111 and ST235 MBL producers carried several resistance and virulence genes. Additionally, the presence of type I-C and type I-E clustered regularly interspaced short palindromic repeats (CRISPR)/Cas locus was observed in ST235 and ST395 isolates, respectively. In conclusion, our findings confirmed the clonal spread of ST111 P. aeruginosa, carrying the VIM-2-encoding integron In59, in the University Hospital of Larissa (UHL). In addition, they highlighted the important role of high-risk clones, ST111 and ST235, in the successful dissemination and establishment into hospital settings of clinically important pathogens carrying resistance determinants.

Highlights

Pseudomonas aeruginosa is an opportunistic pathogen causing a wide range of infections, including pulmonary infections, wound and sepsis
Twenty-four P. aeruginosa isolates had minimal inhibitory concentrations (MICs) to meropenem of 4–8 mg/L and were categorized as susceptible at increased exposure, whereas 96 isolates had MIC >8 mg/L and were categorized as resistant according to the 2019 European Committee on Antimicrobial Susceptibility Testing (EUCAST) definition
We analyzed the molecular characteristics of P. aeruginosa isolates belonging to the I and R susceptibility category according to meropenem MICs, recovered during surveillance program in University Hospital of Larissa (UHL) in 2018

Summary

Introduction

Pseudomonas aeruginosa is an opportunistic pathogen causing a wide range of infections, including pulmonary infections, wound and sepsis. P. aeruginosa show a great tendency to form biofilms on medical devices [1]. P. aeruginosa express virulence factors, like exotoxins, proteases and pigment. These factors help the bacterium to facilitate successful colonization and infection across a wide range of environments. P. aeruginosa show a high prevalence of antimicrobial resistance. 13% of P. aeruginosa, causing infections, are multidrug-resistant (MDR) strains. Recently, the World Health Organization (WHO) has considered P. aeruginosa as a target of high priority for the development of new antibiotics [2]

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