Predominance of metallo-beta-lactamase blaVIM Genes in Clinical Isolates from Health Facilities in Nigeria: Role in Multidrug Resistance Surge

Background: The predominance of metallo-beta-lactamase (MBL) genes in Gram-negative bacteria (GNB) has been reported to contribute immensely in the emergence of multi-drug resistance (MDR) strains in hospital environments worldwide. Aim: This study aimed to investigate the molecular characteristics of MBL genes in MDR-GNB in selected health facilities in Akwa Ibom State, Nigeria. Materials and methods: A descriptive cross-sectional study was conducted in three health facilities in the State. One hundred and sixty (160) samples each of wound, urine and blood were collected aseptically from consented patients and analyzed using standard laboratory procedures. Identification, antibiotic susceptibility testing and phenotypic detection of MBL-producers were done using the VITEK®2 system, Kirby-Bauer disc diffusion and imipenem+EDTA CDT, respectively. Polymerase chain reaction was used to investigate the characteristics of MBL encoding genes: blaVIM, blaNDM and blaIMP. Results: Out of 135 GNB identified, 60.7% exhibited MDR and 53(39.3%) were MBL-producers. Of the MBL genes screened, only the blaVIM was detected in 5(23.8%) of the 21 selected strains screened. The breakdown of blaVIM gene detection rate among isolates from wound, blood and urine samples were 20%, 11.1% and 3.4%, respectively. The GNB that harboured the blaVIM genes were Serratia marcescens, Klebsiella pneumoniae and Escherichia coli recovered from wounds as well as Proteus mirabilis and Pseudomonas aeruginosa recovered from blood and urine samples, respectively. Conclusion: Findings of this study highlight the importance of the blaVIM gene in conferring multidrug among the Gram-negative bacteria, and the need to establish antimicrobial resistance surveillance network and policy to determine appropriate empirical treatment regimen among hospitals in the State.