Assessment of antimicrobial resistant bacteria and antimicrobial resistance genes in hospital, pharmaceutical and agricultural settings in Lagos state, Nigeria

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BACKGROUND: Human activities in diverse sectors contribute to the surge of antimicrobial resistance. This study assessed wastewater and soil from selected environments in Lagos, Nigeria, for the presence of antibiotic-resistant bacteria (ARB), as well as their resistance genes. Lagos is a city with densely populated urban and slum settlements characterized by poor drainage systems into which waste effluents are emptied. This highlights Lagos as an ideal site for the study, as it could be an epicenter for the breeding and transmission of ARB.METHODS: A total of 12 samples, comprising four soil and eight water samples, were collected and analyzed from selected environments, including an abattoir, a tertiary hospital, a pharmaceutical company, and farms. The physicochemical parameters of the samples were characterized using standard protocols. Bacterial strains were isolated through culture, and antimicrobial resistance profiles were determined using the Kirby-Bauer method. Resistance genes were detected through specific primer-dependent real-time quantitative PCR, from the extracted genome.RESULTS: The physicochemical analyses of the wastewaters revealed higher biochemical oxygen demand (BOD: 326.7±4.51-821.0±2.0 mg/L), dissolved oxygen (DO: 1.05±0.07-4.27±0.14 mg/L), and total dissolved solids (TDS: 0.14±0.0-5.18±0.012 g/L) than the recommended limits. Soil samples contained total organic carbon, organic matter (OM), and phosphate, ranging from 0.14 (±0.031)-9.77 (±0.091), 0.24 (±0.050)-16.90 (±0.164), and 2.22 (±0.046)-5.28 (±0.308) mg/kg, respectively. Klebsiella pneumoniae (21.5%) predominated among the isolated bacteria, which also included Enterobacter spp., Providencia stuartii, Salmonella spp., Pseudomonas spp., and Vibrio parahaemolyticus. Enterobacter aerogenes isolated from abattoir effluents exhibited resistance to 7 antibiotics with a Multi-Antibiotic Resistance Index of 0.58. Thirty-four (52.3%) bacterial strains were resistant to pefloxacin. blaTEM resistance gene was detected in all (100%) samples with mean Ct values ranging from 15.60±0.12 to 27.93±0.06, while blaCMY and qnrS were detected in 58% and 83% of the samples respectively.CONCLUSIONS: This study reveals that effluents from the assessed environments are hotspots for the dissemination of antibiotic resistance within the ecosystem.