Distribution of genotypes of F-specific RNA bacteriophages in human and non-human sources of faecal pollution in South Africa and Spain

Aims: To assess whether the distribution of genotypes of F-specific RNA bacteriophages reflects faecal pollution of human and animal origin in water environments. Methods and Results: Stool samples, animal feedlot waste slurries and a wide variety of faecally polluted waters were studied in South Africa and Spain. Genotyping was performed by plaque and spot hybridization with genotype-specific probes. Only genotypes II and III were detected in human stool. Animal faeces contained predominantly, but not exclusively, genotypes I and IV. Raw hospital and municipal sewage contained mostly genotypes II and III, whereas genotypes I and II prevailed in settled sewage, secondary treated sewage and non-point diffuse effluents from developing communities. Abattoir wastewaters contained mostly genotypes I and IV. No differences were observed between the distribution of genotypes in Spain and South Africa. Conclusions: Although the association of genotypes II and III with human excreta and I and IV with animal excreta was statistically significant, the results suggest that the association cannot be used for absolute distinction between faecal pollution of human and animal origin. Significance and Impact of the Study: This study contributes greatly to understanding the usefulness of genotypes of F-specific RNA bacteriophages in source tracking of faecal wastes.