Genotypic and Phenotypic Characterization of MBL Genes in Pseudomonas aeruginosa Isolates from the Non-hospital Environment

Abstract

The non-hospital environment particularly poultry farms and abattoirs are fast becoming reservoir channels for the transmission of antibiotic resistant bacteria including those that produce metallo beta-lactamases (MBLs). Foodproducing animal’s habouring multidrug resistant bacteria including those that produce metallo-beta-lactamases (MBLs) poses health risks to the human population. This study investigated the prevalence of blaIMP-1 and blaVIM-1 MBL genes in Pseudomonas aeruginosa isolates from food-producing animals by multiplex PCR technique. Anal swab samples (n=120) were bacteriologically analyzed on cetrimide selective agar for the selective isolation of P. aeruginosa isolates. Antibiogram was carried out as per the Clinical and Laboratory Standard Institute (CLSI) criteria. The production of MBLs was detected phenotypically and genotypically using the modified Hodges test method and multiplex PCR technique respectively. DNA products were run on 1.5 % agarose gel, and visualized using a UV transilluminator at 260 nm. Data was analyzed statistically using SPSS version 23.0. Out of the 120 anal swab samples, a total of 43 (35.8 %) isolates of P. aeruginosa was bacteriologically recovered. The P. aeruginosa isolates were found to be resistant to ampicillin (88.4 %), cefotaxime (81.4 %), gentamicin (79.1 %), sulphamethoxazole-trimethoprim (72.1 %), oxacillin (76.7 %), nitrofurantoin (76.7 %), meropenem (62.8 %), ofloxacin (67.4 %), imipenem (65.1 %) and cloxacillin (69.8 %). MBL was phenotypically detected in 15 (34.9 %) isolates of P. aeruginosa. However, the multiplex PCR technique significantly confirmed MBL production in only 12 (27.9) isolates of P. aeruginosa (p<0.001) that harboured the blaIMP-1 MBL genes. The blaVIM-1 MBL genes were not detected in the MBL positive P. aeruginosa phenotypes. The P. aeruginosa isolates that harboured the blaIMP-1 MBL genes were found to be multiply resistant. This study reported for the first time the prevalence of blaIMP-1 MBL genes from P. aeruginosa isolates from anal swab samples of food-producing animals in Abakaliki, Nigeria. The long-term exposure of food-producing animals to antibiotics could cause accumulation of antibiotic resistance determinants in the gut microbiota of these animals.

Keywords

• pseudomonas aeruginosa
• abattoir
• mbl genes
• imp-1
• vim-1
• multidrug resistance
• nigeria