Persistence of Vibrio mimicus During Inter-epidemic Period Associated with Anabaena variabilis

Vibrio mimicus, the causative agent of diarrhea, is one of the major public health issues in low-income countries like Bangladesh. Epidemiological studies of diarrhea in Bangladesh have demonstrated that surface-water sources can act as foci of infection. The present investigation was aimed to determine the role of blue green alga, Anabaena variabilis in the survival of Vibrio mimicus in laboratory microcosms. Survival of culturableV. mimicus in microcosms was monitored using drop plate method on TTGA plate. Viable but nonculturable (VBNC) V. mimicus were detected using fluorescent antibody (FA) and PCR techniques. V. mimicus was detected in association with？ A. variabilis for up to 10 days in a culturable state; whereas in algal water and control water the bacteria remained culturablestate upto 5 days and 3 days respectively. The VBNC state of V. mimicus in association with A. variabilis was detected up to 60 days in microcosms. However, the bacteria were unable to detect after 25 days in algal water and after 12 days in control water. The VBNC state of V. mimicus was detected in the microcosms by PCR technique taken sample at different time interval. Both the fluorescent antibody technique and PCR results revealed that V. mimicus can survive longer period (as VBNC) in association with A. variabilis compared to control and algal water. The results suggested that, A. variabilis may act as a reservoir of V. mimicus in an aquatic environment. In the present study, pH was lower in case of algal water than control water. It may cause the hydrogen ion secretion by A. variabilis. The salinity of algal water was increased compare to control water in the present study. A. variabilis may excrete various salts during the association with V. mimicus. Further epidemiological study is required to trace its ecological niche.