Fecal Indicators and Zoonotic Pathogens in Household Drinking Water Taps Fed from Rainwater Tanks in Southeast Queensland, Australia

Abstract

ABSTRACTIn this study, the microbiological quality of household tap water samples fed from rainwater tanks was assessed by monitoring the numbers ofEscherichia colibacteria and enterococci from 24 households in Southeast Queensland (SEQ), Australia. Quantitative PCR (qPCR) was also used for the quantitative detection of zoonotic pathogens in water samples from rainwater tanks and connected household taps. The numbers of zoonotic pathogens were also estimated in fecal samples from possums and various species of birds by using qPCR, as possums and birds are considered to be the potential sources of fecal contamination in roof-harvested rainwater (RHRW). Among the 24 households, 63% of rainwater tank and 58% of connected household tap water (CHTW) samples containedE. coliand exceeded Australian drinking water guidelines of <1 CFUE. coliper 100 ml water. Similarly, 92% of rainwater tanks and 83% of CHTW samples also contained enterococci. In all, 21%, 4%, and 13% of rainwater tank samples containedCampylobacterspp.,Salmonellaspp., andGiardia lamblia, respectively. Similarly, 21% of rainwater tank and 13% of CHTW samples containedCampylobacterspp. andG. lamblia, respectively. The number ofE. coli(P= 0.78),Enterococcus(P= 0.64),Campylobacter(P= 0.44), andG. lamblia(P= 0.50) cells in rainwater tanks did not differ significantly from the numbers observed in the CHTW samples. Among the 40 possum fecal samples tested,Campylobacterspp.,Cryptosporidium parvum, andG. lambliawere detected in 60%, 13%, and 30% of samples, respectively. Among the 38 bird fecal samples tested,Campylobacterspp.,Salmonellaspp.,C. parvum, andG. lambliawere detected in 24%, 11%, 5%, and 13% of the samples, respectively. Household tap water samples fed from rainwater tanks tested in the study appeared to be highly variable. Regular cleaning of roofs and gutters, along with pruning of overhanging tree branches, might also prove effective in reducing animal fecal contamination of rainwater tanks.