[Bacteriologic quality of water from the Rhine and its tributaries in the Rhine-Neckar region. II. Salmonellas--public health significance and health risks].

Salmonella-infections, the epidemiology and the spread of these germs into the environment are a serious hygienic problem even today. Probably one of the most important reservoirs of germs is the water of rivers and lakes. Its relevance for the infective chain in the overcrowded region Rhein-Neckar was examined very insufficiently until now. Even though, the municipal, two-stepped purification-plants are widely improved, the pollution of the pre-floating compartments with Salmonellae seems to be always a problem. In 1982, 1983 and 1986 164 water-specimens were collected at 34 sites along the river Rhine and its affluxes in the Rhine-Neckar-Region and tested for the occurrence of Salmonellae. 35 serotypes could be isolated 156 fold in a 200-ml-specimen. Along the collecting-sites with a higher concentration of waste-water they could be found even in smaller volumes of water (2.5 ml, 12 isolates). Especially those species could be identified, which had been reported at the public-health-departments in Mannheim, Ludwigshafen and Heidelberg as the cause of gastroenteritis during the test-period. Some divergences were observed due to the different resistance of the serotypes. The negligent deal with quite often high-contaminated surface-water (in agriculture, for private purposes) and the high environmental stability of many Salmonella-serotypes results in many infect-chains in the tested Rhine-Neckar-Region. This is one of several explanations for the still high incidence of gastroenteritis.