Genetic study of extended spectrum beta-lactamase genes; bla-TEM, blaOXA-10, blaSHV and per-1 in pseudomonas aeruginosa from hospital-acquired infections

Abstract

Pseudomonas aeruginosa, an opportunistic pathogen, is a major contributor to hospital-acquired infections. This Gram-negative bacterium relies on aerobic respiration and cannot ferment. Various mechanisms of antibiotic resistance closely link to its pathogenicity. This study aimed to determine how common the bla-TEM, blaOXA-10, blaSHV, and per-1 genes were in Pseudomonas aeruginosa samples taken from hospitalized patients. We conducted a retrospective cross-sectional analysis on 100 isolates of the bacterium. The double-disc test detected extended-spectrum beta-lactamase (ESBL) activity and assessed antibiotic susceptibility. Using polymerase chain reaction (PCR), we found that the bla-TEM, bla-SHV, blaOXA-10, and per-1 genes were present. Pseudomonas aeruginosa isolates were highly resistant to meropenem (80%), imipenem (77%), piperacillin (77%), and ceftazidime (76%). However, they were not resistant to colistin. 91% of the isolates exhibited multidrug resistance (MDR), and 76% phenotypically showed ESBL production.Gene analysis revealed that bla-TEM was the most prevalent (38%), then per-1 (31%), bla-SHV (15%), and OXA-10 (9%). We identified the bla-TEM gene in 50.8% of ESBL-positive Pseudomonas aeruginosa, the per-1 gene in 40.8%, and the bla-SHV and OXA-10 genes in 19.7% and 2.6% respectively. The phenotypic method failed to detect ESBL activity in 24 isolates with the per-1 gene and 7 isolates with the OXA-10 gene. In conclusion, clinical isolates of Pseudomonas aeruginosa show a high prevalence of ESBL activity, but reliance on phenotypic methods alone may overlook some cases. The most frequently detected ESBL-associated genes are bla-TEM, followed by per-1, bla-SHV, and OXA-10. Additionally, Pseudomonas aeruginosa isolates demonstrate a high incidence of multiple drug resistance.