Wastewater from Social Housing Networks as a Reservoir of Antibiotic-Resistant <i>Vibrio</i>: Phenotypic Identification and Seasonal Variability in Yaoundé, Cameroon

A study was carried out to search for bacteria of the genus Vibrio in the effluents of the social housing networks (called SIC camps) in the city of Yaoundé. Wastewater samples were taken at various points in the SIC camps in selected locations in Yaoundé. In total, seven sampling points were selected. Bacteria were isolated on TCBS (Thiosulfate Citrate Bile Salts Sucrose) medium on a Petri dish using the surface spread technique. Standard analytical techniques were used to measure some abiotic parameters. Susceptibility testing to ten antibiotics was performed on 29 Vibrio isolates (19 dry season isolates and 10 wet season isolates). The species identified were V. cholerae, V. alginolyticus, V. parahaemolyticus, V. vulnificus and V. mimicus. The abundance of these bacteria varied between 0 and 4.40 log CFU/mL. V. parahaemolyticus was the most abundant species. Thus, their abundance has undergone spatio-temporal and seasonal variations and seems to be weakly influenced by the physico-chemical parameters considered in this study. The susceptibility of bacteria to ten antibiotics (ceftazidime, colistin, gentamicin, doxycycline, azithromycin, ciprofloxacin, nalidixic acid, chloramphenicol, amoxicillin + ac. clavulanic and cefotaxime) was carried out on 29 isolates (i.e., 19 isolates in the dry season and 10 isolates in rainy season) of Vibrio. In the dry season, the highest resistance rate was that of V. cholerae (60%) while in the rainy season, the highest resistance rate was that of V. alginolyticus (70%). In addition, the species identified have multi-resistance ranging from 2 to 7 different antibiotics.