Monitoring microbiological changes in drinking water systems using a fast and reproducible flow cytometric method.

Flow cytometry (FCM) is a rapid, cultivation-independent tool to assess and evaluate bacteriological quality and biological stability of water. Here we demonstrate that a stringent, reproducible staining protocol combined with fixed FCM operational and gating settings is essential for reliable quantification of bacteria and detection of changes in aquatic bacterial communities. Triplicate measurements of diverse water samples with this protocol typically showed relative standard deviation values and 95% confidence interval values below 2.5% on all the main FCM parameters. We propose a straightforward and instrument-independent method for the characterization of water samples based on the combination of bacterial cell concentration and fluorescence distribution. Analysis of the fluorescence distribution (or so-called fluorescence fingerprint) was accomplished firstly through a direct comparison of the raw FCM data and subsequently simplified by quantifying the percentage of large and brightly fluorescent high nucleic acid (HNA) content bacteria in each sample. Our approach enables fast differentiation of dissimilar bacterial communities (less than 15 min from sampling to final result), and allows accurate detection of even small changes in aquatic environments (detection above 3% change). Demonstrative studies on (a) indigenous bacterial growth in water, (b) contamination of drinking water with wastewater, (c) household drinking water stagnation and (d) mixing of two drinking water types, univocally showed that this FCM approach enables detection and quantification of relevant bacterial water quality changes with high sensitivity. This approach has the potential to be used as a new tool for application in the drinking water field, e.g. for rapid screening of the microbial water quality and stability during water treatment and distribution in networks and premise plumbing.

[A concept to improve wet-lab training in ENT surgery]. / Ein Konzept zur Verbesserung von Präparationskursen in der HNO-Heilkunde.

BACKGROUND: In literature and scientific societies no binding methodical-didactic recommendations or guidelines exist in order to design surgical training courses. The educating institutions plan, organise and evaluate the educational program on their own initiative. MATERIAL AND METHODS: Through a research project surgical training courses were investigated through structured surveys, expert discussions with course responsibles and trainers and analysis of participant's questionnaires. The investigation was performed by an pedagogical-psychological research institution. First implementations were installed and immediately included in the running process of evaluation. RESULTS: From the evaluation, specific alterations in the organisational and micro didactic process were implemented. In addition, changes in a long term process had to be implemented such as: (a) conception of the trainer role, (b) giving feedback and judge performance and (c) provide contents in a sophisticated manner. CONCLUSION: For advanced medical training providers a long term cooperation with a pedagogical institution seems to be highly advisable.