부산대학교 도서관

This study assessed the influence of waterfowl on the microbiological quality of village amenity ponds and the distribution of pathogenic bacteria in these ponds using both conventional and molecular genomic techniques. To investigate the influence of waterfowl on the bacteriological quality of amenity ponds, two village ponds in East Yorkshire, one with abundant waterfowl and one without waterfowl, were sampled at monthly intervals from June 2001 to January 2002. A further five ponds (two with waterfowl and three without) were also sampled on three occasions between August and November 2001. Escherichia coli, faecal streptococci and to a degree Clostridium perfringens, were more abundant in the water and sediment of ponds with waterfowl. Salmonella was detected, during summer, in the sediment of a pond with waterfowl. There was a significant correlation between E. coli and the number of waterfowl. These results suggested that the microbiological quality of amenity ponds might be adversely affected by waterfowl. All water samples from ponds with waterfowl had faecal indicators at higher concentrations than EU requirements for bathing waters. Although these ponds are not used for bathing, skin contact and accidental ingestion of water should be avoided. Problems associated with the detection of Campylobacter from amenity ponds with waterfowl were investigated. Water and sediment samples were collected from three ponds between August and December 2003. The analysis of three different volumes of water (10, 100 and 1000 ml) and three volumes of sediment (0.1, 1.0 and 5.0 ml) by enrichment culture showed that the filtration of a large volume of turbid pond water or the use of a large volume of sediment to assess the presence of Campylobacters may be counterproductive and may not yield presumptive isolates due to competition by background microflora during enrichment culture. Thus pilot studies to establish appropriate volumes of environmental water or sediment samples should be undertaken before routine detection of Campylobacter is begun. To test the hypothesis that waterfowl are a significant source of Campylobacter and Salmonella in amenity ponds, fresh duck faeces and samples of run-off water that flowed into the ponds were screened by conventional methods for the presence of these bacteria between August 2003 and January 2004. Both biochemical and morphological methods and PCR were used to confirm presumptive isolates. DNA sequencing of PCR products was used to type confirmed isolates. Campylobacter was isolated from both faeces and run-off water (as well as from water and sediment). Thus the faeces of waterfowl and rain-related run-off are both potential sources of Campylobacters to the ponds. Different environmental Campylobacter species were, however, found to be of different origin: Campylobacter jejuni from duck faeces and C. coli from run-off. Furthermore, different ponds apparently had a different principal source of Campylobacter - faeces or run-off. Salmonella, in contrast, was not reliably isolated from duck faeces or run-off, nor this organism found in pond water, and only occasionally was it found in sediment. The direct application of PCR to turbid pond water to detect naturally-occuring Campylobacters was evaluated. The presence of the organism in small numbers with the presence of humic material and other PCR inhibitors, may have led to the negative results that were obtained. However, the use of a selective enrichment step followed by PCR facilitated the rapid detection of Campylobacter.