Bacteriophages in bathing wàters: A feasibility study on the development of a method based on bacteriophages for the determination of microbiological quality of bathing waters

Projecte: Project report. BCR Information. EU project KINA19506ENC_001. EUROPEAN COMMISSION. Community Research. DG XII/C - Competitive and Sustainable Growth Programme. Published by EU Directorate General ΧΠ - Science, Research and Development ISBN 92-828-9145-3Informe final projecte europeu aigües de bany i bacteriòfagsMethods for the detection and enumeration of somatic coliphages, F-specific RNA bacteriophages and bacteriophages infecting Bacteroides fragilis had been standardised and validated. Conditions for the preparation, transport and distribution of bacteriophage reference materials and preservation of samples had been defined. A method based on flocculation with Mg(OH2) with concentration efficiencies from about 40% was settled to concentrate phages from bathing waters. All methods were successfully implemented in routine laboratories all around the EU. Data on the occurrence of bacteriophages as compared to E. coli and Enterococci are available from diverse situations encountered in the EU. Results allow to conclude that the potential of phages for the determination of the microbiological quality of bathing waters merits to be considered since their determination is feasible and their behaviour in natural water differs from the behaviour of bacterial indicators and consequently they add valuable information

Occurrence and levels of indicator bacteriophages in bathing waters throughout Europe

Somatic coliphages, F-specific RNA bacteriophages, bacteriophages infecting Bacteroides fragilis, Escherichia coli and enterococci were counted in bathing waters in the late spring and summer. We tested fresh and marine bathing waters from North, South, East and West Europe expected to contain between 100 and 500 E coli per 100 ml, although wider ranges were sometimes found. Bacteriophages were counted after concentration, since a preliminary study proved that this step was necessary to obtain positive counts. During monitoring, a first-line quality control with reference materials for bacteria and bacteriophages was performed by all the laboratories participating in the study. The same microbes were also counted in raw sewage samples from various areas in Europe, where the bacterial indicators and the three groups of bacteriophages were detected in roughly the same numbers. All groups of bacteriophages were detected in both fresh and marine bathing waters throughout Europe. Reliable and complete results from 147 samples showed that for log-transformed values, E. coli and bacteriophages were slightly correlated. However, the slope of the regression line changed according to E. coli concentration and the correlation diminished when this concentration was close to zero per 100 ml. The ratios between E coli and phages in bathing waters differed significantly from those in sewage. The relative amounts of bacteriophages, mainly somatic coliphages and phages infecting Bact. fragilis RYC2056, increased in bathing waters with low E coli concentration, especially in seawater samples containing < 100 E coli per 100 ml. The relationship of bacteriophages with respect to enterococci paralleled that of bacteriophages with respect to E coli. Somatic coliphages and bacteriophages infecting Bact. fragilis are useful to predict the presence of some pathogens with the same origin as present bacterial indicators but with higher survival rates. (C) 2002 Elsevier Science Ltd. All rights reserved