Detection of blaSPM-1 and blaSIM-2 Metallo-β-Lactamases Genes in Imipenem-Resistant Pseudomonas aeruginosa Clinical Isolates Recovered from Two University Hospitals in Egypt

Objectives: Unraveling mechanisms whereby Pseudomonas aeruginosa becomes resistant to carbapenems through testing 114 non-duplicate P. aeruginosa clinical isolates for their susceptibility to various classes of antibiotics and scrutinizing the production of metallo-β-lactamases (MBLs) by tested isolates. Methods: Susceptibility testing of P. aeruginosa to different antibiotics was determined by Kirby-Bauer disk diffusion method and MBLs production by tested isolates was studied phenotypically and genotypically and PCR products were confirmed by sequencing Results: All tested clinical isolates showed eminent resistance to the majority of tested antibiotics and 14 isolates were imipenem (IPM)-resistant. Furthermore, IPM-resistant isolates were verified to be MBLs-producers. MBLs-encoding genes blaSIM and blaSPM genes were detected by PCR where four isolates were found to harbor blaSPM gene while only one isolate harbored blaSIM gene. The correct size of PCR products of blaSIM and blaSPM genes were sequenced and sequences were submitted to the GenBank databases and assigned the accession numbers KX452682 and KX452683 for blaSIM-2 and blaSPM-1, respectively. Conclusion: Here, we report the emanation of P. aeruginosa clinical isolates harboring blaSPM-1 and blaSIM-2 genes. This may reflect the substantial increase in the rate of imipenem resistance due to MBL in P. aeruginosa clinical isolates from Egypt. Early detection and infection-control practices are of the best antimicrobial strategy for combating this organism.