Water quality assessment of a Central European River - does the Directive 2000/60/EC cover all the needs for a comprehensive classification?

Over the last decades, European rivers have mostly shared the same fate. Until the mid 1980s many of them were in rather bad shape. Nobody would have thought about using the waters for recreation. However, continuous efforts over the last three decades have achieved success and today's water quality has changed to the better. This obvious change in water quality, which was proved by investigations done on the basis of the European Directive 2000/60/EC framework for Community action in the field of water policy, made people consider using the rivers for recreation or irrigation. In the present study a Central European River was investigated from hygienic perspectives (faecal indicators), and its toxicological status was examined - both of which are parameters which are not included in the Directive 2000/60/EC. The pivotal question was whether these parameters provide essential and additional information about the river's status and its quality. In general, the monthly values for all sampling points from the toxicological tests correlated with the determined physical and chemical statuses according to the national water management plan. Once, however, the toxicological values did increase significantly. This detection of a single toxicological burst within a year of observation underlines the applicability of the tests as screening methods for the detection of toxic substances. Moreover, our microbiological investigations show high numbers of faecal indicators and Salmonellae. These results are not consistent with the apparently good quality of the river. Therefore faecal indicators, which are directly related to the discharge of waste water, should be an integral part of the procedure of water classification.

Virulence and antimicrobial resistance genes in human MRSA ST398 isolates in Austria.

This study determined the genetic background of virulence and resistance genes of MRSA ST398 in Austria. From 2004 up to 2008 a total of 41 human isolates of MRSA ST398 were investigated for virulence and resistance gene patterns using DNA microarray chip analysis. Highly similar virulence gene profiles were found in 29 (70·7%) of the isolates but genes encoding Panton-Valentine leukocidin, enterotoxins, or toxic shock syndrome toxin were not detected. Genes conferring resistance to tetracycline and erythromycin-lincosamide were common as all but one of the isolates exhibited tetM and/or tetK, which are involved in tetracycline resistance, and 12 (29·9%) were positive for ermC, conferring resistance to erythromycin/lincosamide. SplitsTree analysis showed that 40 isolates were closely related. Changes in virulence and resistance gene patterns were minimal over the observed time period.

Comparison of extended-spectrum-ß-lactamase (ESBL) carrying Escherichia coli from sewage sludge and human urinary tract infection.

For many years, extended-spectrum-beta-lactamase (ESBL) producing bacteria were a problem mainly located in medical facilities. Within the last decade however, ESBL-producing bacteria have started spreading into the community and the environment. In this study, ESBL-producing Escherichia coli from sewage sludge were collected, analysed and compared to ESBL-E. coli from human urinary tract infections (UTIs). The dominant ESBL-gene-family in both sample groups was bla(CTX-M), which is the most prevalent ESBL-gene-family in human infection. Still, the distribution of ESBL genes and the frequency of additional antibiotic resistances differed in the two sample sets. Nevertheless, phenotyping did not divide isolates of the two sources into separate groups, suggesting similar strains in both sample sets. We speculate that an exchange is taking place between the ESBL E. coli populations in infected humans and sewage sludge, most likely by the entry of ESBL E. coli from UTIs into the sewage system.