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.

Background: Pseudomonas aeruginosa is one of the most important causative agents among the hospital acquired infections, especially in ICU and burn units. Enzymatic inactivation of aminoglycosides by aminoglycoside-modifying enzymes is the main mechanism of resistance to these antibiotics in Pseudomonas aeruginosa. The aim of this study was to study the aminoglycoside resistance and ant (2”)-I in Pseudomonas aeruginosa isolated from burn specimens in Yazd, Iran.

Materials and Methods: This cross-sectional study was carried out on Pseudomonas aeruginosa isolates (no=73) during July 2014 to April 2015. All burn wound samples were initially identified by the standard biochemical methods and their aminoglycoside resistance was studied using the disc diffusion method according to CLSI recommendations. PCR method was carried out for the detection of aminoglycoside resistance using ant (2”)-I gene specific primers.

Results: Forty (54.8%) out of 73 cases were male (mean age 29±2.25 years). The resistance rates as determined by the disk diffusion method were: Kanamycin (89%), Gentamicin (67.1%), Tobramycin (58.9%) and Amikacin (60.3%). The PCR results showed that 63 (86.3%) of the isolates were harbored the ant (2”)-I gene.

Conclusion: The results of this study show that resistance to aminoglycosides is high in pseudomonas aeruginosa isolated from burn wounds. The presence of gene ant (2”)-I was widely reported. In addition, there was a significant relationship between this gene and resistance to aminoglycosides.