Prevalence of blaVEB and blaTEM genes, antimicrobial resistance pattern and biofilm formation in clinical isolates of Pseudomonas aeruginosa from burn patients in Isfahan, Iran

Abstract Background Pseudomonas aeruginosa is very common in burn wound infections. The biofilm formation and the production of beta-lactamase enzymes have made this bacterium resistant to many antibiotics. This study aimed to evaluate antibiotic resistance, biofilm formation, and the frequency of strains that carry blaTEM and blaVEB. Methods A cross-sectional study was carried out from March 2017 to March 2018 on 103 clinical isolates of P. aeruginosa, identified from 420 burn wound infection samples by phenotypic tests. Antibiotic resistance and biofilm formation were evaluated by the Kirby-Bauer disk diffusion method and microtiter plate assay, respectively. Double disk synergy test (DDST) was used for phenotypical detection of Extended-spectrum beta-lactamases (ESBL) producing isolates. ESBL genes were detected by polymerase chain reaction (PCR). Result Of 103 strains isolated from burn wound infection, 91.3% were multiple drug resistance (MDR). The resistance to levofloxacin was the highest (93.2%). The ability of biofilm formation was observed in three groups: 47.6% of isolates had no biofilm formation, 38.8% were weak, and 13.6% showed moderate biofilm formation. The prevalence of DDST-confirmed ESBL was 54 (43.9%). The isolates had 28.15% and 21.35% of blaVEB and blaTEM genes, respectively. Conclusion This study showed that MDR strains are common in burn infections. Biofilm formation and produce beta-lactamase enzymes also showed a growing trend.