The prevalence, antimicrobial susceptibility, virulence, and antimicrobial resistance genes of multidrug-resistant Vibrio parahaemolyticus recovered from Oreochromis niloticus

Vibrio parahaemolyticus is associated with severe food-borne illness in humans as well as substantial financial setbacks in the fishing sector. To investigate the prevalence, pathogenicity, virulence, as well as the resistance patterns of V. parahaemolyticus retrieved from Oreochromis niloticus, 180 O. niloticus (moribund fish; n = 120 and apparently healthy; n = 60) were indiscriminately collected from Lake Manzala, Egypt. Consequently, the clinical inspection, necropsy finding, and bacteriological analysis were performed. All the retrieved isolates tested positive for the groEL species-specific gene. Herein, the prevalence of V. parahaemolyticus in the collected fish was 8.9% (16/180), whereas the liver was the organ most prominently affected. PCR revealed that the most prevalent virulence-determinant genes associated with V. parahaemolyticus were the toxR and tlh genes (100% for each), then tdh (73.3%) and trh (26.7%) genes. Furthermore, 40% (18/45) of isolated V. parahaemolyticus were extensively drug-resistant (XDR) to seven antimicrobial classes and have bla_TEM, bla_OXA, sul1, aadA, ermB, and tetA genes. Additionally, 17.8% (8/45) of the obtained V. parahaemolyticus were multidrug-resistant (MDR) to three antimicrobial classes and owned bla_TEM, ermB, and aadA genes. The pathogenicity assay accentuated the correlation between cumulative mortality and the virulent characteristics exhibited by the inoculated strain. Definitely, 77% mortality was recorded within eight days in fish injected with a virulent V. parahaemolyticus strain. Briefly, this research accentuated the occurrence of XDR V. parahaemolyticus in fish specifying a public health concern. The emerging MDR and XDR V. parahaemolyticus frequently harbored toxR, tlh, and tdh virulence genes, and bla_TEM, bla_OXA, sul1, aadA, ermB, and tetA or tetB antimicrobial resistance genes.