F‐specific RNA bacteriophages and sensitive host strains in faeces and wastewater of human and animal origin

Abstract

Faeces of humans, pigs, cattle and chickens were investigated for the presence of somatic coliphages, F-specific bacteriophages and Escherichia coli strains sensitive to infection by F-specific phages. Attention was given to the possible effect of age and use of antiboitics on the prevalence of the FRNA phages and sensitive E. coli strains. Somatic coliphages were often detected in high numbers in all types of faeces. In contrast, FRNA phages were rarely detected in faeces from humans and cattle but more often in faeces from pigs and adult chickens. Samples from young chickens (with or without antibiotics) were consistently positive for FRNA phages (up to 3 .times. 106 pfu/g). F-specific RNA phages were found in substantial numbers (> 103 pfu/ml) in a variety of wastewaters: domestic, hospital, slaughterhouses and occasionally in ''grey water''. Their origin in wastewater was not clear. Strains from faeces usually belong to the serogroups I and IV. These types also found in wastewater, as were group II and II strains. Serogroup II phages were abundant in wastewater of human origin but rare in faeces. Escherichia coli strains sensitive to infection by F-specific phages were common in faeces (overall 290/1081: 27%). No strains with fully derepressed F-pilus synthesis were detected among the sensitive strains. It is conclded that the occurrence of F-specific RNA bacteriophages in water points to sewage pollution rather than fecal pollution; the mechanism of replication of these organisms in wastewater is not understood.