Attachment of non-culturable toxigenicVibrio cholerae01 and non-01 andAeromonasspp. to the aquatic arthropodGerris spinolaeand plants in the River Ganga, Varanasi

Non-cultivable, pathogenic 01 and non-01 Vibrio cholerae and Aeromonus spp.were resuscitated from aquatic arthropods and plant homogenate respectively, by rabbit ileal loop (RIL) assay.These organisms adhered to the aquatic arthropod Gerris spinolae and various species of phytoplankton in the Kiver Ganga, but failed to grow after direct inoculation on artificial media except for only 10 homogenates of the arthropod.The number of non-01 V. cholerue and Aeromonus recovered on direct inoculation of G. spidae homogenates were in the order of IO'-IOh whereas those of the Ganga water were IO*-IO3 ml-'.A total of 1 I9 strains of 01 and non-01 V. rholerue and Aeromonas spp.(69 isolates from G. spinolae and 50 from aquatic plants) were recovered from the loop contents.The results indicate that production of the enzyme chitinase by 01 and non-01 V. cholerue and Aeromonas spp.might facilitate their adsorption and multiplication on different species of zoo-and phyto-plankton.Most of the isolates were enterotoxic, haemolytic and resistant to different antibiotics.This study suggests that species of zoo-and phyto-planktons, until now not reported to be associated with 01 and non-01 V. choierae, may act as reservoirs of these organisms as well as different species of Aeromonas in a fresh-water riverine ecosystem.