Members of the Vibrio genus are autochthonous inhabitants of aquatic environments and play vital roles in sustaining the aquatic milieu. The genus comprises about 100 species, which are mostly of marine or freshwater origin, and their classification is frequently updated due to the continuous discovery of novel species. The main route of transmission of Vibrio pathogens to man is through drinking of contaminated water and consumption inadequately cooked aquatic food products. In sub-Saharan Africa and much of the developing world, some rural dwellers use freshwater resources such as rivers for domestic activities, bathing, and cultural and religious purposes. This review describes the impact of inadequately treated sewage effluents on the receiving freshwater resources and the associated risk to the rural dwellers that depends on the water. Vibrio infections remain a threat to public health. In the last decade, Vibrio disease outbreaks have created alertness on the personal, economic, and public health uncertainties associated with the impact of contaminated water in the aquatic environment of sub-Saharan Africa. In this review, we carried out an overview of Vibrio pathogens in rural water resources in Sub-Saharan Africa and the implication of Vibrio pathogens on public health. Continuous monitoring of Vibrio pathogens among environmental freshwater and treated effluents is expected to help reduce the risk associated with the early detection of sources of infection, and also aid our understanding of the natural ecology and evolution of Vibrio pathogens.

Treated sewage harbours pathogenic microbes, such as enteric bacteria and protozoa, are capable of causing several diseases. Some of these are emerging pathogens sometimes recovered in the absence of common water quality indicator organisms. The possibility of selected treatments plants serving as momentary reservoirs of Vibrio pathogens during a non-outbreak period was assessed. The occurrence and diversity of Vibrio pathogens were monitored for one year (December 2016 to November 2017) in the treated effluents and upstream and downstream areas of the receiving water bodies of two wastewater treatment plants (WWTPs), designated AL and TS. Physicochemical parameters of TS and AL WWTPs’ water samples were analysed using a multi-parameter meter (Hanna, model HI 9828, Padova, Italy) and a turbidimeter (HACH, model 2100P, Johannesburg, South Africa). Water samples were augmented with alkaline peptone water and cultured on thiosulfate citrate bile salts sucrose agar at 37 °C for 24 h. The recovered probable pathogens were confirmed via PCR amplification, using primers specific for Vibrio species of public health significance. The distribution of Vibrio species positively and significantly (p < 0.01) correlated with turbidity (r = 0.630), temperature (r = 0.615), dissolved oxygen (r = 0.615), pH (r = 0.607), biological oxygen demand (r = 0.573), total dissolved solid (r = 0.543), total suspended solid (r = 0.511), electrical conductivity (r = 0.499), residual chlorine (r = 0.463) and salinity (r = 0.459). The densities of Vibrio species were found to be significantly higher (p < 0.05) in effluents from both AL and TS WWTPs than upstream and downstream of the receiving rivers across the sampling regime. Furthermore, the maximum Vibrio species density across the sampling regime were observed during the warmer Summer and Spring season. Moreover, six medically important Vibrio species were detected in the water samples, indicating that the methods employed were efficient in revealing that WWTPs are potential reservoirs of Vibrio pathogens, which could pose a substantial public health risk if the receiving water is used for domestic purposes. Our findings further strengthen existing calls for the inclusion of emerging bacterial pathogens, including Vibrio species, as water quality indicators by the South African Department of Water Affairs. Hence, we recommend regular monitoring of treated effluents and receiving water bodies to ensure early control of potential outbreaks of vibriosis and cholera.

Enterococci are part of the normal intestinal flora of humans and animals and are increasingly recognized as significant human pathogens and capable of causing major therapeutic challenges. The aim of this study was to isolate, identify and determine the antimicrobial susceptibility pattern of Enterococcus species in two local cheese sample collected from Akungba and Ikare. The isolation of Enterococcus was carried out using standard culture-based techniques. Antimicrobial susceptibility profile of the Enterococcus species was determined using disk diffusion method. A total number of 93 presumptive Enterococcus species were recovered from forty two different samples over a period of three months. The bacterial count observed on the Bile Aesculin agar ranged from 1.5x104 cfu/ml to 4.6x104 cfu/ml with Akungba sample having the highest bacterial load of 4.6x104 cfu/ml. The Morphology and biochemical characteristics of suspected Enterococcus spp. isolated from the cheese sample revealed Enterococci feacalis as the isolated bacteria. The isolated Enterococcus species were tested against a panel of six antibiotics which include Penicillin G, Vancomycin, Tetracycline, Nitrofurantoin, Ciprofloxacin and Imipenem. It was observed that the isolates were susceptible to tetracycline, imipinem and ciprofloxacin while they are resistant to ciprofloxacin and vancomycin. The prevalence of Enterococci was confirmed with Enterococcus feacium and Enterococcus faecalis as the predominant species isolated in both cheese sample. The ability of Enterococcus species to survive a range of adverse environments allows multiple routes of cross-contamination of Enterococci in causing human disease, including those from food. Overall, greater understanding of the ability of Enterococcus species to survive stresses, of virulence traits and especially of increasing antibiotic resistance, is needed in order to fully appreciate the complexity of Enterococcus species in causing disease.