Molecular Assessment of Resistance and Virulence Potential of Vibrio Species Isolated From Dumpsites in Port Harcourt, Nigeria

Abstract

Background: Dumpsites have the potential to serve as reservoirs for various medically important bacteria and their virulence and resistance gene markers. For Vibrio spp., numerous genes associated with virulence have been identified in environmental strains. Due to the specific growth requirements of Vibrio spp., such strains can often be overlooked. This study aimed to assess the potential of Vibrio spp. isolated from two dumpsites in Port Harcourt, Nigeria, to serve as reservoirs of virulence and resistance genes. Methods: The soil samples were evaluated for the presence of Vibrio spp. following enrichment, using standard microbiological and biochemical test methods. DNA from Vibrio spp. was extracted using the boiling method, and isolates were tested for the presence of four resistance (sxt, strB, BlaTEM, and dfrA1) and four virulence (ctxA, hlyA, tcpA, and toxR) genes. Results: The study found a 40% occurrence of resistance genes and a 10% occurrence of virulence genes, with the strB streptomycin resistance gene being the most commonly detected (42%). Two of the virulence genes (ctxA and tcpA) were not detected. Seven of the test isolates exhibited multiple gene markers, with four gene markers present in each of two isolates. Conclusion: Overall, the study revealed a generally low potential for Vibrio sp. isolated from the dumpsites in Port Harcourt, Nigeria, to act as reservoirs of virulence and resistance genes. Additionally, the study reported an absence of major virulence markers associated with V. cholerae. A concerning finding was the high occurrence (42%) of the strB gene among these environmental isolates.