[Detection of viruses in raw water as a basic tool for risk assessment]. / Nachweis von Viren im Rohwasser als Grundlage einer Risikoabschätzung.

Human pathogenic viruses may end up in surface waters by fecal contamination. However, the German drinking water ordinance requests that pathogens in drinking water should not be present in concentrations constituting a potential danger to human health. Since many viruses do have a very low dose of infection, they have to be sufficiently eliminated in the process of drinking water purification. Waterborne virus outbreaks in Europe, over the last few decades, were mostly linked to noncompliance with the generally accepted codes of practice for drinking water production. The aimed level of protection of drinking water supplies in Germany, however, exceeds prevention of outbreaks by even protecting against sporadic virus infections. Documentation of such a high level of protection is not achieved by end product control alone but requires a process analysis with risk assessment. To do such an analysis, information regarding the presence of viruses in the raw water used for drinking water production, as well as data of virus elimination rates during purification processes, are of major importance. This paper presents suggestions for implementation of such a risk assessment, focusing on the evaluation of raw water quality.

[Special aspects of microbiological monitoring of drinking water quality]. / Ausgewählte Aspekte bei der mikrobiologischen Uberwachung der Trinkwasserqualität.

The new drinking water ordinance (TrinkwV 2001) entered into force in 2003. In this paper we report about experiences with monitoring microbiological quality of drinking water. Special problems, for instance requirements concerning the quality of raw water, new and "old" microbiological parameters, microbiological methods, assessment of parametric values, especially in the case of values higher than the imperative value, are also described. Possible developments in this field are discussed. The paper should support microbiological laboratories, public health officers and other public authorities in monitoring and assessment of drinking water quality.

Isolation of Arcobacter butzleri in raw water and drinking water treatment plants in Germany.

A total of 147 "Campylobacter-like" strains were isolated from six drinking water treatment plants within a two year investigation period. The strains were characterized by bio-, and serotyping according the scheme for Arcobacter butzleri. The result was that 100 strains were typed as Arcobacter butzleri, 17 strains as Arcobacter butzleri-like and 6 strains as Campylobacter jejuni/coli. 24 strains were typed as Arcobacter spp. The strains isolated from the treatment plants showed the same serotypes as described for human isolates. Therefore the spread of Arcobacter organisms via the drinking water path must be suspected.

PCR-mediated DNA fingerprinting of atypical campylobacter strains isolated from surface and drinking water.

This study shows that typing through polymerase chain reaction (PCR) can be used to differentiate between strains of Campylobacter and Arcobacter, whereas by means of conventional biotyping Arcobacter might be identified as atypical Campylobacter. Microaerophilic "campylobacter-like" organisms were isolated from several drinking water treatment plants as well as environmental sources. The strains were characterized by biotyping and PCR amplification of Campylobacter flaA/flaB and 16s-rRNA Arcobacter butzleri-specific genes.

Isolation of Arcobacter butzleri from a drinking water reservoir in eastern Germany.

Microaerophilic "campylobacter-like organisms" (CLO) were isolated from a drinking water reservoir in Germany during a period of some months. The strains were characterized by biotyping (API Campy), serotyping and SDS-Disc-gelelectrophoresis as Arcobacter butzleri. Now this facultative humanpathogen species was first described in Germany. With respect to the drinking water treatment, the hygienic importance of the findings is given.

[The occurrence of aeromonads in a drinking water supply system]. / Untersuchungen zum Vorkommen von Aeromonaden in einem Trinkwasserversorgungssystem.

This study concerns with the occurrence of aeromonads, coliforms and colony counts in a drinking water supply. Aeromonas contents were detected in the range of 15.0 to greater than 2,400/100 ml in the raw water samples of the man made lake. After the drinking water treatment process including fast sand filtration and chlorination aeromonads indicated in comparison to total coliforms and colony counts early and significant an after-growth of maximal 240 aeromonads/100 ml in the peripheric drinking water supply. Drinking water samples characterized by a higher water temperature resulted in the highest contents of aeromonads. The Aeromonas-Species Aeromonas sobria and Aeromonas hydrophila were isolated most frequently with 56.9 and 37.4 percent, respectively. The role of aeromonads as an indicator of after-growth in drinking water supplies is discussed.