Dissemination of metallo-β-lactamase in Pseudomonas aeruginosa isolates in Egypt: mutation in blaVIM-4.

This study was designed to investigate the prevalence of metallo-β-lactamase (MBL) in Pseudomonas aeruginosa isolates collected from Suez Canal University Hospital in Ismailia, Egypt. Antibiotic susceptibility testing and phenotypic and genotypic screening for MBLs were performed on 147 isolates of P. aeruginosa. MICs were determined by agar dilution method for carbapenem that was ≥2 μg/mL for meropenem. MBL genes were detected by multiplex and monoplex PCR for P. aeruginosa-harbored plasmids. Mutation profile of sequenced MBL genes was screened using online software Clustal Omega. Out of 147 P. aeruginosa, 39 (26.5%) were carbapenem-resistant isolates and 25 (64%) were confirmed to be positive for MBLs. The susceptibility rate of P. aeruginosa toward polymyxin B and norfloxacin was 99% and 88%, respectively. Identification of collected isolates by API analysis and constructed phylogenetic tree of 16S rRNA showed that the isolates were related to P. aeruginosa species. The frequency of blaGIM-1, blaSIM-1, and blaSPM-1 was 52%, 48%, and 24%, respectively. BlaVIM and blaIMP-like genes were 20% and 4% and the sequences confirm the isolate to be blaVIM-1, blaVIM-2, blaVIM-4, and blaIMP-1. Three mutations were identified in blaVIM-4 gene. Our study emphasizes the high occurrence of multidrug-resistant P. aeruginosa-producing MBL enzymes.