Background: Pseudomonas aeruginosa is a gram-negative, non-fermentative bacillus and one of the most common opportunistic human pathogen causing 10-15% of nosocomial and burn wound infections worldwide. These bacteria are resistant to most of the antibiotics. This study aimed to investigate the frequency of extended spectrum β-lactamase (ESBL) and metallo-β-lactamase (MBL) enzymes in P.aeruginosa strains isolated from burn wounds.

Materials and Methods: In this descriptive cross-sectional study, 180 wound specimens were collected from patients hospitalized in burn hospital and then cultured. The suspected colonies were identified using the conventional biochemical methods. Susceptibility testing was performed using the Kirby-Bauer method. Moreover, the Combination Disk and E.test methods were used for the determination of ESBLs and MBL, respectively.

Results: Fifty-four (30%) out of 180 cultured samples were identified as p.aeruginosa 12 (22%) and 16 (29.5%) isolates were ESBLs and MBL producer, respectively. Overall, 42 (79%), 40 (74%), 40 (74%), 38 (70%), 35 (66%) and 34 (62%) isolates were resistant to ceftizoxime, imipenem, gentamycin, piperacillin, cefepime, meropenem and ertapenem, respectively.

Conclusion: Results reveal that the antimicrobial resistance and prevalence of ESBLs and MBL producing P.aeruginosa strains is increasing in our hospital and it is necessary to perform susceptibility testing, control risk factors and reasonably prescribe the appropriate antibiotics. Considering the diversity of ESBL and MBL classes and their prevalence in different areas, performing molecular research is needed.