Distribution and antibiogram of Vibrio species from hospital wastewater in Southwest, Nigeria

Abstract

Introduction: the continuous generation of wastewater and its release into the environment with little or no treatment remains a threat to the environment and public health. We examined the prevalence and antibiotic susceptibility profiles of Vibrio species isolated from untreated wastewater samples from Ondo State Specialist Hospital Okitipupa, Nigeria, as part of the global efforts to provide information for containing the spread of resistant infections.

Methods: twelve hospital wastewater samples were collected aseptically and transported to the laboratory for analysis. The samples were processed on thiosulphate citrate bile salt sucrose agar and colonies typical of Vibrio species were selected for further identification. All isolates were confirmed by polymerase chain reaction (PCR) using Vibrio-specific primers and the PCR products were sequenced for species identification. The susceptibility profiles of the isolates were determined by the Kirby-Bauer disc diffusion method.

Results: twenty-nine (58%) of 38 presumptive isolates were confirmed as Vibrio by PCR, while 23 (60.5%) isolates were screened up to species level by sequencing. Six different species following the trend: 26.1% V. fortis and V. algivorus, 17.4% V. cholerae, 13.0% V. panuliri, 8.7% V. stylophorae and V. parahaemolyticus were identified. The isolates were commonly resistant (73.9%-91.3%) to doxycycline, tetracycline, erythromycin and meropenem. The least resistance rate (17.4%) was observed against amikacin and cotrimoxazole. All isolates were multidrug-resistant, with multiple antibiotic resistance (MAR) indices exceeding the 0.2 recommended limit.

Conclusion: this study has shown that untreated hospital wastewater is a reservoir for diverse strains of multiply resistant Vibrio species. Therefore, it is essential to adequately treat hospital wastewater to eliminate these emerging pollutants and set up a monitoring scheme to evaluate the treatment plants' effectiveness to reduce the pollutants' impact on the environment and the population.