The Frequency of VIM 2, 3, 9, 11 and VIM all among Metallo-beta-Lactamase Producing Pseudomonas aeruginosa

Abstract

Introduction: Antibiotic resistance crisis has always been a serious problem for human health and many hospitalized patients are affected worldwide. Pseudomonas aeruginosa is a gram-negative pathogen and one of the most common causes of nosocomial infections. The main mechanism of resistance to beta-lactam antibiotics is the presence of metallo-beta-lactamase (MBL) enzymes. Most of the MBL genes are found in plasmids. The aim of this study was to evaluate the frequency of MBL-producing P. aeruginosa isolates caused by VIM-all and VIM 2, 3, 9, 11and16 genes. Materials & Methods: Antimicrobial susceptibility of 127 clinical isolates of P. aeruginosa was determined using the standard Kirby-Bauer disk diffusion method according to Clinical and Laboratory Standard Institute (CLSI). Combined-disk test was used for phenotypic determination of MBLs-producing isolates. After DNA extraction, VIM-all and in specific, VIM 2, 3, 9, 11 and 16 genes were amplified using PCR method. Findings: A total Of 127 clinical isolates of P. aeruginosa, 62 isolates (49%) were resistant to imipenem and 31 isolates (24.5%) showed phenotypic evidences of MBL production. Moreover, among imipenem resistant strains VIM-all genes were found in 12.5% of cases, but the VIM 2-3-9-11 and 16 genes were not detected in samples. Discussion & Conclusions: The results obtained in this study suggest that in P. aeruginosa, the highest antibiotic resistance observed was to cefazolin (98%) followed by nalidixic acid (91%) and the least resistance were to ciprofloxacin (31%). One of the reasons for this trend is the growth of antibiotic-resistant bacteria and the known mechanisms of bacterial resistance.

Keywords

• Metallo-beta-lactamase
• Pseudomonas aeruginosa
• Antibiotic resistance
• VIM gene