Isolation, molecular identification and antibiotics susceptibility of Salmonella serotypes isolates from bats in Osun State, Nigeria

Bats (Chiroptera) are widely distributed in nature and are important reservoir host of many zoonotic bacterial pathogens such as Salmonella species. Bats faecal samples were collected from Ile-Ife, Osogbo and Ilesa and were streak cultured on Salmonella-Shigella agar and incubated aerobically at 37 °C. Non-lactose fermenting colonies were picked for further identification using biochemical tests and confirmation using Analytical Profile Index 20E Kit. The antibiotics susceptibility test on the confirmed Salmonella serotypes was performed using Kirby-Bauer’s disc diffusion technique. The degree of genetic relatedness and the phylogenetic diversity between the strains of the isolates were determined by random amplified polymorphic DNA (RAPD-PCR). Five different Salmonella spp were identified across the three locations; Salmonella arizonae, S. bongori, S. typhi, S. enterica, S. choleraesuis. S. arizonae was most abundant and common to the three locations (Ile-Ife, Osogbo and Ilesa). Resistance to antibiotics varied greatly among the isolates across the locations. All the isolates were susceptible to ciprofloxacin. Resistance to commonly available antibiotics such as gentamicin, oflaxacin, meropenem. eterpenem, sulphomethaxozole, tetracycline and nitrofuranton was significantly low (P ≥ 0.5) compared with other classes of antibiotics tested across the three locations. Resistance to augmentin (93.37%), cefuroxime (83.84%) ceftazidime (68.42%) were relatively high across the three locations. The random amplified polymorphic DNA revealed genetic polymorphism among the isolates and the strains were highly heterogeneous base on the distribution of different nucleotide sequences.