CHARACTERIZATION OF FECAL STREPTOCOCCI FROM SOME NEW-ZEALAND EFFLUENTS AND RECEIVING WATERS

Different proportions of component species of faecal streptococci were found in New Zealand sewage, animal processing effluents, and animal faeces. Enterococcus faecium was the major species in raw sewage (43-6 5%), followed by E. faecalis (19-40%) or E. durans (14-23%). Meat proc essing effluent usually had a higher proportion of E. durans (37-73%) than sewage. Enterococci, mainly E. durans (34%), dominated in sheep f aeces, but Streptococcus bovis comprised 53% of the faecal streptococc i in cattle faeces. In sewage-contaminated groundwater, a survival pat tern of E. faecalis > E. faecium > E. durans > S. equinus > S. bovis w as predicted. The proportion of E. durans was low in rivers impacted b y animal wastes, and decreased during treatment of sewage and meatwork s effluent and after both effluents were mixed with sea water. Thus, s uperior survival of E. faecium and E. faecalis means that they are lik ely to be the dominant species in receiving waters, irrespective of wh ether the pollution is of human or animal origin. Faecal coliform : fa ecal streptococci/ enterococci ratios were similar in raw sewage and m eat processing effluents (generally > 3), but superior enterococcus su rvival caused a decrease in ratios in groundwater and sea water. Thus, these ratios are probably not useful in distinguishing between human and animal pollution sources in New Zealand receiving waters.