Detection of virulence genes in bacteria associated with microplastics from selected Rivers in Ado-Ekiti, Nigeria

This study investigated the detection of virulence genes in bacteria associated with microplastics in selected rivers in Ado-Ekiti, Nigeria. Water samples were collected biweekly over a period of 24 months from the rivers (Ureje, Emirin, Ogbese, Odo-Ayo and Elemi). Isolation of bacteria, antibiotics susceptibility testing of the isolates and detection of virulence genes were carried out using standard methods. The bacteria isolated include Escherichia coli, Klebsiella pneumoniae, Salmonella typhi, Shigella dysenteriae, Bacillus subtilis, B. licheniformis, Pseudomonas aeruginosa, Proteus mirabilis, Micrococcus luteus, Enterobacter aerogenes, B. cereus, Citrobacter freundii, Aeromonas spp, Proteus vulgaris. Staphylococcus aureus and Staphylococcus epidermidis. The antibiotic susceptibility profile of the isolates showed that both Gram negative and Gram positive bacterial isolates exhibited multiple antibiotic resistance. Of the 423 bacterial isolates, 226 were positive to biofilm formation, 78 to heamolysin formation, 87 to phospholipase and 76 to gelatinase production. Virulence genes stn, spvC and invA were detected in Salmonella typhi (EM22), fimH and sxt1genes were detected in E. coli (Urj.23) and Shigella dysenteriae (EM6), fimH, rmpA and entB genes were detected in Klebsiella pneumoniae (Ogb4). In Bacillus cereus (EM4), nheA, hblC and hblD genes were detected while oprL, exoS and oprI genes were detected in Pseudomonas aeruginosa (ELE12). The findings of this study suggests that water from the rivers are of poor microbial qualities, the bacterial isolates were multiple antibiotic resistant with various virulence genes. Therefore, water from the rivers must be adequately treated before use.