Characterisation of the resistome and virulome of Pseudomonas aeruginosa isolates from patients with ventilatorassociated pneumonia

ABSTRACT : Introduction/objective: Ventilator-associated pneumonia (VAP) is the hospital-acquired infection with the greatest impact on patient outcomes and health care costs. Endogenous colonization by aerobic gram-negative bacteria such as Pseudomonas aeruginosa play a pivotal role in the pathogenesis of VAP. The aim of this work was the characterisation of the resistome and virulome of a collection of P. aeruginosa isolates from patients with VAP collected during a multicentre study. Material and methods: We analysed 38 isolates (1 per patient) of P. aeruginosa from patients with VAP. Minimum inhibitory concentrations (MICs) of 16 different antibiotics were determined by broth microdilution according to the Clinical and Laboratory Standard Institute (CLSI) and the European Committee on Antimicrobial Susceptibility Testing (EUCAST) clinical breakpoints. The complete genomes of all the isolates were sequenced using the MiSeq platform (Illumina) to determine their clonal relationship, as well as the presence of antibiotic resistance and virulence related genes. Results: According to antibiotic resistance, 10.5% (n=4) of the isolates were multi-susceptible and 23.7% (n=9) moderately resistant, while 21.1% (n=8) were multidrug-resistant and 44.7% (n=17) were extensively resistant. Forty-five genes related with antibiotic resistance were detected: blaGES-7 and blaVIM (1,2 and 20) were observed on extensively resistant isolates. According to the results obtained from the Virulence finder database (VFDB), the virulome of the whole population was made up of 294 genes, among which the most significant were the effectors (exo-) from the type III secretion system.Máster en Biología Molecular y Biomedicin