Comparative Resistance of Bacteriophages Active against Bacteroides fragilis to Inactivation by Chlorination or Ultraviolet Radiation

Abstract

In order to assess the potential usefullness of bacteriophages active against Bacteroides fragilis for the monitoring of viral disinfection in environmental samples, the sensitivity to chlorination and to UV irradiation of bacteriophage B40-8 was evaluated in comparison to that of poliovirus type 1 (LSc2ab), simian rotavirus SA11, coliphage f2, Escherichia coli and Streptococcus faecalis. The inactivation of the different microorganisms by chlorine or UV treatment was monitored in tap water and sewage. The results indicated that viruses persisted significantly (p<0.05) longer than bacteria in the presence of both disinfectants. Phage B40-8 was the most resistant microorganism to chlorination (p<0.05) while coliphage f2 was the most resistant to UV irradiation. In the latter, phage B40-8 was nevertheless as resistant as poliovirus and rotavirus. As expected, all microorganisms were significantly (p<0.05) more resistant to both disinfection procedures in sewage than in tap water. These studies lead to the suggestion of the use of bacteriophage B40-8, instead of indicator bacteria, for the monitoring of viral disinfection in sewage-polluted water.