Occurence of vancomycin-resistant Enterococcus faecium in patient isolates and aquatic environment during a period between 2004 and 2010

Real-time PCR detection of Pseudomonas aeruginosa in clinical and municipal wastewater and genotyping of the ciprofloxacin-resistant isolates

Real-time quantification of Pseudomonas aeruginosa was performed in various wastewater systems including clinical, municipal wastewaters and inflow from a wastewater treatment plant. The highest concentrations of P. aeruginosa-specific targets were detected in clinical wastewaters. Limitations of the detection system resulting from inhibition or cross-reaction were identified. Ciprofloxacin-resistant P. aeruginosa strains were isolated after specific enrichment from clinical and municipal wastewaters. In some cases they were also cultivated from effluent of a wastewater treatment plant, and from its downstream river water. A total of 119 isolates were phenotypically characterized as ciprofl…

Detection of antibiotic-resistant bacteria and their resistance genes in wastewater, surface water, and drinking water biofilms.

Abstract In view of the increasing interest in the possible role played by hospital and municipal wastewater systems in the selection of antibiotic-resistant bacteria, biofilms were investigated using enterococci, staphylococci, Enterobacteriaceae, and heterotrophic bacteria as indicator organisms. In addition to wastewater, biofilms were also investigated in drinking water from river bank filtrate to estimate the occurrence of resistant bacteria and their resistance genes, thus indicating possible transfer from wastewater and surface water to the drinking water distribution network. Vancomycin-resistant enterococci were characterized by antibiograms, and the vanA resistance gene was detect…

Molecular monitoring of inactivation efficiencies of bacteria during pulsed electric field treatment of clinical wastewater

Aims:  The applicability of an alternative wastewater disinfection concept based on the pulsed electric field (PEF) treatment is tested with molecular biology techniques using clinical wastewaters. Methods and Results:  Hospital wastewater was treated with the PEF technology. The inactivation efficiencies of bacteria were successfully monitored with real-time polymerase chain reaction (PCR). As the differentiation between living and dead bacterial cells is important for the determination of the disinfection efficiency, propidium monoazide (PMA) was applied. PMA selectively penetrates cells with compromised membranes and intercalates into the DNA inhibiting a subsequent PCR amplification. Th…

Detection of primary DNA damage in Chlamydomonas reinhardtii by means of modified microgel electrophoresis.

The assessment of genotoxic potential in surface water requires test methods, among which are those that detect initial DNA damage in organisms of aquatic biocenosis. The microgel electrophoresis (MGE) "comet assay" was applied to a ubiquitous unicellular green alga (Chlamydomonas reinhardtii) to detect DNA damage caused by genotoxins. For this, the test protocol described by Singh NP et al. [Exp Cell Res 175: 184-191, 1988] was modified. Major modifications were the use of alkaline lysis buffer with ionic detergents and the reduction of preincubation and electrophoresis times. Short-time exposure of Chlamydomonas to the well-known genotoxicants 4-nitroquinoline-1-oxide (4-NQO), N-nitrosodi…