Longevity of pathogenic bacteria especially Salmonella in cistern water.

Cistern-collected rain water which is used as process water for toilet flushing, cleaning purposes, garden irrigation and linen washing, was experimentally contaminated with pathogenic bacteria, Salmonella enteritidis, Yersinia enterocolitica and Campylobacter jejuni. The longevity of those pathogens was investigated considering different temperatures and contents of organic materials. Neither Salmonella enteritidis, Yersinia enterocolitica nor Campylobacter jejuni are able to grow at temperatures of 5 degrees C, 15 degrees C, 20 degrees C or 37 degrees C. The most sensitive pathogen was Campylobacter jejuni which showed rapidly decreasing of colony counts at 15 degrees C as compared with Yersinia enterocolitica or Salmonella enteritidis. For Salmonella enteritidis the decrease of bacterial concentrations was higher at 37 degrees C than at 5 degrees C. Increasing the concentrations of organic compounds by addition of bacteriological pepton or addition of extreme++ amounts of pidgeon feces lowers the rate of bacterial death but an increase in colony counts could not be observed at the different temperatures investigated. The elimination of salmonella is supported if the cisterns are layered with a biofilm and sediment. So it could be confirmed, that raised amounts of organic material, pidgeon feces together with optimal temperatures which can be observed accidentally in rain water cisterns can not enhance growth of enteropathogenic bacteria.