Molecular screening of antibiotic-resistant determinants among multidrug-resistant  clinical isolates of Proteus mirabilis from SouthWest Nigeria.

Olumuyiwa Samuel Alabi1, Nuno Mendonça, Olufemi Ezekiel Adeleke, Gabriela Jorge da Silva2,

1. Department of Pharmaceutical Microbiology, University of Ibadan, Nigeria, West Africa.
2. Center for Neurosciences and Cell Biology, University of Coimbra, Coimbra, Portugal
3. Faculty of Pharmacy, University of Coimbra, Coimbra, Portugal

Abstract
Background:Globally, and particularly in developing countries, the menace of anti-microbial resistance is an accelerating problem. In Nigeria, increase in bacterial resistance has been phenotypically established but due to high cost, few molecular studies have been reported.

Objectives: This study screened for presence of transferable resistance genes and mobile genetic elements (MGEs) such as integron among multi-drug resistant (MDR) P. mirabilis.

Methods: A total of 108 P. mirabilisstrains collected from five tertiary hospitals in SouthWest Nigeria were subjected to antibiotic susceptibility study using disc-diffusion method. Transferable resistance genes and MGEs were amplified using Polymerase chain reaction (PCR) analysis and amplicons sequenced.

Results:Varied resistance was observed against all the antibiotics tested. About 56% of the isolates were MDR including those from 0-12 years old children. PCR analysis revealed the presence of aac(6’)-Ib (33.3%), plasmid mediated quinolone resistance (PMQR) genes [qnrA(36.7%), acc(6’)-Ib-cr(5%)], TEM (48.3%), CTX-M (6.7%) and integrons class 1 (58.3%) and class 2 (26.7%). Sequencing analysis revealed blaTEM-1, blaCTX-M-15 associated with ISEcp1 and eight different arrays of gene cassettes: aadA1, aadA1-qacH, aadB-aadA2, aadA5, dfrA7, dfrA15, dfrA17, dfrA17-aadA5.

Conclusion:Transferable resistance genes in association with MGEs are present in Nigerian P. mirabilisthus their potential in disseminating resistance.

Keywords: Multidrug resistance, resistance determinants, integrase, gene cassettes, Proteus mirabilis.