Second collaborative study on analysis of bacteriophages in bathing waters
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Type
Report
Language
en
Date
1999-08-25
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Title
Second collaborative study on analysis of bacteriophages in bathing waters
Translated Title
Tweede ringonderzoek voor analyse van bacteriofagen in zwemwater
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Abstract
Het tweede internationale ringonderzoek met bacteriofagen in zwemwater werd in maart 1998 georganiseerd. Vijftien Europese laboratoria (inclusief het organiserende laboratorium) namen deel aan de studie. De studie bestond uit twee delen: (1) Analyse van natuurlijk besmette standaard monsters for de bepaling van somatische colifagen (SOMCPH), F-specifieke fagen (bevattende het totaal aantal F-specifieke fagen: FTOTPH en F-specifieke DNA-fagen: FDNAPH) en fagen van Bacteroides fragilis (BFRPH); (2) Toepassing van een concentreringstechniek (gebaseerd op flocculatie) op een mengsel van faag-referentiematerialen (oX174 voor SOMCPH, MS2 voor FTOTPH en B40-8 voor BFRPH). Tijdens de discussie met de deelnemende laboratoria over de resultaten van de studie werd besloten om een aantal resultaten niet te gebruiken bij verdere statistische analyse vanwege opgetreden technische problemen bij de laboratoriumanalyse. Analyse van de overgebleven resultaten resulteerde voor de studie met de natuurlijk besmette monsters in de volgende waarden voor de herhaalbaarheid (r): 1.63 - 2.34 en reproduceerbaarheid (R): 3.10 - 5.72, voor de verschillende groepen van bacteriofagen. Er was meer variatie tussen de resultaten dan bij de analyse van referentiematerialen (met reincultures van standaard fagen). Dit werd waarschijnlijk veroorzaakt door een combinatie van extra Poisson variatie tussen de faag-tellingen van de natuurlijk besmette standaard monsters en de moeilijkheid van het interpreteren van platen afkomstig van natuurlijk besmette monsters. De resultaten van de concentrerings techniek toonden lage recovery van faag oX174 (2.2% - 16.4%) en variabele recovery van fagen MS2 (12.7% - 99.4%) en B40-8 (42.5% - 142.9%).<br>
A second international collaborative study on bacteriophages in bathing waters was organised in March 1998. Fifteen European laboratories (including the organising laboratory) participated in the study. It consisted of two parts: (1) Analysis of naturally polluted standard samples for the enumeration of somatic coliphages (SOMCPH), F-specific phages (including the total number of the F-specific phages, FTOTPH, and the F-specific DNA phages, FDNAPH) as well as phages of Bacteroides fragilis (BFRPH); (2) Application of a concentration technique (based on flocculation) to a mixture of phage reference materials (oX174 for SOMCPH, MS2 for FTOTPH and B40-8 for BFRPH). In agreement with the participating laboratories, some of the data were excluded for further analysis because of technical problems in several laboratories. Analysis of the remaining data for the part of the study dealing with the naturally polluted standard samples resulted in values for the repeatability (r) varying from 1.63 - 2.34, and for the reproducibility (R) from 3.10 - 5.72 for the different groups of bacteriophages. The variation in these results was greater than those in which reference materials (with pure cultures of standard phages) were analysed. This was probably caused by a combination of extra Poisson variation in phage numbers in naturally polluted standard samples and the difficulties of interpreting plates of natural samples. Analysis of the results from the concentration technique showed low recovery of phage oX174 (2.2% - 16.4%), and variable recovery of phages MS2 (12.7 % - 99.4 %) and B40-8 ( 42.5% - 142.9 %).<br>
A second international collaborative study on bacteriophages in bathing waters was organised in March 1998. Fifteen European laboratories (including the organising laboratory) participated in the study. It consisted of two parts: (1) Analysis of naturally polluted standard samples for the enumeration of somatic coliphages (SOMCPH), F-specific phages (including the total number of the F-specific phages, FTOTPH, and the F-specific DNA phages, FDNAPH) as well as phages of Bacteroides fragilis (BFRPH); (2) Application of a concentration technique (based on flocculation) to a mixture of phage reference materials (oX174 for SOMCPH, MS2 for FTOTPH and B40-8 for BFRPH). In agreement with the participating laboratories, some of the data were excluded for further analysis because of technical problems in several laboratories. Analysis of the remaining data for the part of the study dealing with the naturally polluted standard samples resulted in values for the repeatability (r) varying from 1.63 - 2.34, and for the reproducibility (R) from 3.10 - 5.72 for the different groups of bacteriophages. The variation in these results was greater than those in which reference materials (with pure cultures of standard phages) were analysed. This was probably caused by a combination of extra Poisson variation in phage numbers in naturally polluted standard samples and the difficulties of interpreting plates of natural samples. Analysis of the results from the concentration technique showed low recovery of phage oX174 (2.2% - 16.4%), and variable recovery of phages MS2 (12.7 % - 99.4 %) and B40-8 ( 42.5% - 142.9 %).<br>
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Publisher
Rijksinstituut voor Volksgezondheid en Milieu RIVM
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EU
EU