Widespread Occurrence of Antibiotic Resistance Genes in Bacterial Isolates from River Ala in Akure, Nigeria

Antibiotic resistance genes can be naturally occurring in bacteria or can be acquired through horizontal gene transfer. This study investigated the antibiotic resistance genes in bacterial isolates from River Ala. Water samples were collected bi-weekly over a period of 24 weeks from three representative points in River Ala. The load and identities of bacteria in the water samples were determined using standard microbiological methods. Antibiotic susceptibility pattern of the isolates were determined using disc diffusion method. Antibiotic resistance genes (ARGs) were detected using molecular methods. Results showed that the total plate count ranged from 7.0 × 101 to 1.3 × 104 cfu/100 ml and total enterobacteriaceae count ranged from 9.2 × 102 to 4.2 × 104 cfu/ 100 ml. The bacterial isolates detected in the samples were Escherichia coli, Salmonella enterica, Klebsiella pneumonia, Proteus mirabilis and Enterobacter cloacae Antibiotic susceptibility pattern of the isolates revealed that all the bacterial isolates had 100% resistance to penicillin, while 92.86% of the isolates were resistant to nalidixic acid and ceporex. ARGs such as blaNDM, blaTEM, blaSHV and tetA were detected in Escherichia coli, Salmonella enterica and Enterobacter cloacae. There were positive correlations between Escherichia coli, Salmonella enterica and Enterobacter cloacae, ARGs such as blaNDM, blaTEM, blaSHV and tetA. The findings of this study demonstrated the presence of ARGs such as blaNDM, blaTEM, blaSHV and tetA in Escherichia coli, Salmonella enterica and Enterobacter cloacae in water samples from River Ala. Understanding the presence and dynamics of these genes in aquatic environments is essential for managing public health risks.