Plasmid-Mediated Genes Were Responsible for the Resistance and Spread of Metallo Beta-Lactamase (MBL)-Producing Pseudomonas Aeruginosa Isolates in Poultry Milieus

Abstract

Bacterial resistance to antibiotics is a public health menace that needs urgent efforts to mitigate and forestall their transmission in the general environment. Plasmid-mediated metallo beta-lactamase (MBL) gives bacteria an exceptional ability to transmit resistance genes. This study investigated plasmid-mediated resistance in MBL P. aeruginosa isolates from poultry food chain settings. Cloacal swab samples (n=120) were bacteriologically analyzed for the isolation of P. aeruginosa isolates. Susceptibility studies were performed by the CLSI guideline using selected antibiotics. MBL was phenotypically detected using modified Hodges test, and confirmed using PCR technique. Plasmid curing studies detected the presence of plasmids in the isolates. P. aeruginosa isolates (n=48) showed high levels of reduced susceptibility to cefoxitin (93.8%), imipenem (81.3%), gentamicin (85.4%), amikacin (85.4%), nitrofurantoin (83.3%), ofloxacin (72.9%) and cefotaxime (77.1%). MBL was phenotypically detected in 7 (14%) isolates of P. aeruginosa. The presence of blaIMP-1 and blaIMP-2 MBL genes in P. aeruginosa (n=5) isolates was confirmed by PCR. The PCR did not detect blaVIM-1 and blaVIM-2 MBL genes. The P. aeruginosa isolates were multidrug resistant, with about 50% of the isolates showing multidrug resistance (MDR) to the antibiotics. The genes for MDR in the P. aeruginosa isolates were borne on plasmids, indicating a high possibility of community transmission of MBL resistance genes. Finally, the P. aeruginosa isolates from poultry food chain milieus are multidrug resistant, produce MBL, and harbour their resistance genes on plasmids. Since many antibiotic resistance genes in bacteria are associated with mobile genetic elements (MGEs) like plasmids, it is important to step up actions to mitigate incessant use of antibiotics in poultry and other agricultural practices in Nigeria in order to diminish the evolution and spread of plasmid-mediated resistance which is capable of initiating community acquired infections that may prove difficult to treat in our hospitals with the available antibiotics.