Virulence Constitution of Multi-Drug-Resistant Pseudomonas aeruginosa in Upper Egypt

Ventilator-associated pneumonia caused by Pseudomonas aeruginosa (P. aeruginosa) is a major health-care problem. In this study, we explored the epidemiology of virulence determinants among multi-drug-resistant (MDR) clinical P. aeruginosa isolates from hospitalized patients with ventilator-associated pneumonia in intensive care units in Upper Egypt.

MDR P. aeruginosa isolates were screened for the presence of eight virulence factors and typed by ERIC-PCR.

A total of 39 clinical MDR isolates were selected out of 173 isolated P. aeruginosa showing a combination of adhesion and cytotoxicity virulence patterns, with the detection of aprA, exoU, exoS, lasB, algD, toxA in 74.3%, 58.9%, 46.1%, 41.2%, 30.7%, 20.5% of the isolates, respectively. The MDR isolates were grouped into 13 different virulence profiles according to the pattern of virulence gene distribution. exoU genotype was more predominant among the P. aeruginosa isolates with more than 48% of the isolates harboring this gene alone, 7% harboring both exoU and exoS and 43.5% harboring exoS gene. An intermediate degree of diversity was detected by ERIC-PCR typing where the isolates were clustered in 7 major groups, indicating possible cross-infection within the hospital.

Our results highlight the increased frequency of virulent P. aeruginosa isolates with a shift to the more virulent cytotoxic exoU genotype. Further hospital infection-control measures are mandatory to control the hospital cross-transmission of these highly virulent isolates. This study could vastly be a help to develop efficient treatment policies against P. aeruginosa induced ventilator-associated pneumonia.