Dynamics of abundances of vibrio sp in some rivers: impact of physicochemical factors

A study was carried out to assess the abundance dynamics of Vibrio and the impact of abiotic factors on these dynamics in some surface rivers in the city of Ntui (Center Region). A total of 7 sampling stations were chosen on the Sanaga, Bololo and Ntui-ossombo rivers. Physicochemical parameters such as temperature and dissolved O2 among others were considered. Heterotrophic aerobe bacteria were isolated and counted while bacteria of the genus Vibrio, were isolated, counted and identified by standard methods. The specific richness was assessed. The Shannon and Weaver H 'diversity indices and the Piélou equitability indices respectively made it possible to estimate the diversity and to assess the even distribution of the species in the stand in relation to an equal theoretical distribution for all species. Overall, the values of electrical conductivity (39 to 299 Μs.cm-1), were low and reflect waters of low mineralization. The temperature variations (25 to 30 ° C) observed in the three rivers studied are linked to those of ambient temperature, in fact, the thermal variations of lotic ecosystems match those of air. In total, 4 species of vibrioplankton were isolated in the water of watercourses during the study. These are Vibrio parahaemolyticus, Vibrio cholerae, Vibrio alginolyticus and Vibrio vulinificus in decreasing order of their rate of occurrence and abundance. The high occurrence rates of V. parahaemolyticus and V. cholerae (80%) at the level of the Sanaga River and other stations, would explain the sources of contamination of these pathogenic germs in this locality. It should also be noted that some abiotic parameters such as water temperature between 25 and 28 ° C is a good culture medium for microorganisms in the environment.