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Primer sets specific for 16S rRNA genes were designed for four phylogenetic groups of clostridia known to contain mesophilic cellulolytic species. Specific amplification of these groups from landfill leachate DNA extracts demonstrated the widespread occurrence of clostridia from the Clostridium thermocellum and C. leptum groups. In contrast, the C. botulinum group was never detected, and the C. coccoides-C. lentocellum group was only occasionally detected. Amplification products were analyzed by temporal thermal gel electrophoresis to generate profiles of the clostridial groups and to identify dominant bands. Sequence analysis of 17 landfill clones confirmed that the primers were specific for the clostridial subgroups and that the cloned sequences had a close relationship with known cellulose-degrading clostridia. The primers have therefore been authenticated for use in the rapid identification of clostridia in anaerobic environments.Anaerobic degradation in landfills involves several coordinated groups of microorganisms and follows a process that is typical of waste degradation in anaerobic environments, such as soils, sediment, and sludge. As the primary stage of waste degradation, polysaccharide breakdown is an important limiting factor in anaerobic treatment of waste, which in municipal landfills primarily involves the decomposition of complexed polymers, including cellulose, hemicellulose, and lignin. Although cellulose is an important substrate in landfills, anaerobic degradation is poorly understood, and our knowledge is based on studies using culture-based methods (1). The enumeration of cellulolytic bacteria in landfills has often resulted in low cell counts (10), suggesting that culture-based methods may be underestimating bacterial numbers. The aim of the study reported here was to use information on 16S rRNA gene sequences to develop tools for the specific detection of cellulose-degrading bacteria in landfill sites.It is likely that anaerobic cellulose degradation in landfills is due primarily to bacteria related to the genera Clostridium and Eubacterium. Although very few cellulolytic strains have been isolated from landfill sites, Westlake et al. (15) have identified isolates related to these two groups. The genus Clostridium and its relatives constitute an ancient group whose members exhibit a wide range of phenotypic characteristics. Phylogenetic analysis of 16S rRNA genes shows that the group is very diverse, with deeply branching clusters that include nonclostridial species. Comparison of 16S rRNA genes has allowed the division of the genus Clostridium into subgroups, and cellulose-degrading representatives from genera such as Clostridium, Eubacterium, and Ruminococcus can be found in a number of different clusters (3). However, mesophilic cellulose-degrading strains tend to be found in groups I, III, IV, and XIVab, with group III comprising only cellulose-degrading strains to date.Consequently, we have exploited this clostridial 16S rRNA database to investigate the presence of clostridial subg...

Aims:  Quantitative PCR and a culture method were used to investigate Campylobacter occurrence over 3 years in a watershed located in southern Ontario, Canada that is used as a source of drinking water. Methods and Results:  Direct DNA extraction from river water followed by quantitative PCR analysis detected thermophilic campylobacters at low concentrations (<130 cells 100 ml−1) in 57–79% of samples taken from five locations. By comparison, a culture‐based method detected Campylobacter in 0–23% of samples. Water quality parameters such as total Escherichia coli were not highly correlated with Campylobacter levels, although higher pathogen concentrations were observed at colder water temperatures (<10°C). Strains isolated from river water were primarily nalidixic acid‐susceptible Campylobacter lari, and selected isolates were identified as Campylobacter lari ssp. concheus. Campylobacter from wild birds (seagulls, ducks and geese) were detected at a similar rate using PCR (32%) and culture‐based (29%) methods, and although Campylobacter jejuni was isolated most frequently, C. lari ssp. concheus was also detected. Conclusions:  Campylobacter were frequently detected at low concentrations in the watershed. Higher prevalence rates using quantitative PCR was likely because of the formation of viable but nonculturable cells and low recovery of the culture method. In addition to animal and human waste, waterfowl can be an important contributor of Campylobacter in the environment. Significance and Impact of the Study:  Results of this study show that Campylobacter in surface water can be an important vector for human disease transmission and that method selection is important in determining pathogen occurrence in a water environment.

conducted, which found that concentrations at the top of active, acclimated biofilters typically were in the range of 10 2 to 10 3 ng ATP/cm 3 media. The effect of various biofilter parameters (source water characteristics and quality, pretreatment, hydraulic loading rate, temperature, and sampling depth) on ATP levels is discussed and evaluated using published ATP data. The authors also assess the relationship between ATP and biofilter performance in terms of carbon removal and identify a need for further research in this area.Pharand et al | http://dx.