Abstract

GROWTH KINETICS OF PATHOGENS IN ARTIFICIAL WATER MICROCOSMS

Pandove G* and Sahota P

ABSTRACT

The survival rate of reccurent water borne pathogens isolates Aeromonas hydrophila, Yersinia enterocolitica, Listeria spp. and E.coli was investigated in artificially created water microcosm (tap water, millipore filter water, mineral water and tap water with biofilm ). Both the pathogens A. hydrophila and Yersinia enterocolitica with highest incidence(65-80%) of occurence in drinking water of Punjab showed autochthonous survival rate under copiotropic and oligotropic conditions, E. coli was short lived detected till 60 days in Tap water and Mineral water whereas E.coli count increased gradually from log102.13 to log107.0 on day 90, thereafter sudden decrease in count to log102.0 on 120th day, then on 135th day no viable. Under psychrophilic conditions, Aeromonas hydrophila (log101.92) Yersinia enterocolitica ( log101.60) survival rate was depicted till 135th day and Listeria spp.( log1.77) on 135th day. .Thus study revealed that E.coli is short lived whereas Aeromonas hydrophila better adapted to all the environmental conditions. Therefore it could be better indicator of bacteriological quality of drinking water. The implication of this study is that a water supply may be adjudged fit and safe for human consumption based on the E. coli and coliform standards (ISO10500)whereas in actual sense it contains more deadly pathogens. In addition, due to emphasis on the monitoring of classical pollution indicators, not much is being done with regards to the survival and epidemiology of resistant strains in drinking water, either as free or attached cells. Thus over all studied revealed that, E.coli do not adequately reflect the occurrence of pathogens in drinking water may be due to their relatively high susceptibility to disinfection.

Keywords: E.coli, Aeromonas hydrophila, Yersinia enterocolitica, Listeria spp., Microcosm, survival.