Aims: Scarce knowledge about the distribution of enterococci species in wastewaters limits any statement on their reliability as faecal indicators or the implications of antibiotic resistance transmission by these organisms through the water cycle. Enterococci have been involved in nosocomial infections and the spreading of antibiotic resistance through the food chain. The species distribution of enterococci and the presence of resistant strains to vancomycin and erythromycin were analysed in more than 400 raw and treated urban wastewaters, surface waters receiving these treated wastewaters and hospital wastewaters from three European countries. Methods and Results: A total of 9296 strains were isolated and biochemically phenotyped. The species identification was based on the comparison of biochemical profiles with those of more than 20 000 enterococci isolates from an international study. The prevalence of enterococcal isolates resistant to erythromycin (ERE) and vancomycin (VRE) was also analysed. ERE strains were present in a high proportion in all the studied samples. VRE strains were also isolated in all studied countries despite the time elapsed since the use of antimicrobial glycopeptides in animal production was banned in the European Union. Conclusions: Enterococcus faecalis and Ent. faecium were the most abundant species in all the studied wastewaters. All the studied wastewaters demonstrated high diversity and similar population structure and composition. ERE and VRE isolates were detected in most of the wastewaters. Significance and Impact of the Study: Urban and hospital wastewaters are useful targets for the evaluation of the prevalence of ERE and VRE isolates in the environment. It appears that these bacteria could pass through wastewater treatment plants and be transferred to surface waters.

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Vancomycin-resistant enterococcci (VRE) in Europe are thought to have emerged partly due to the use of the glycopeptide avoparcin in animal husbandry. We compared the occurrence of VRE in geographical regions of Europe in which until 1997 large amounts of avoparcin were used (Spain, United Kingdom, and Denmark) with the occurrence of VRE in Sweden, where avoparcin was banned in 1986. We also studied the relatedness between VRE strains from different regions and habitats. In total, 2,580 samples were collected from humans, animals, and the environment (soil, sewage, recipient water). VRE resistant to 20 g/ml vancomycin were identified in 8.2% of the samples and were found most frequently in raw and treated urban sewage samples (means, 71% and 36% of the samples, respectively), pig manure (17%), and hospital sewage (16%). The proportions of VRE-positive sewage samples were similar in Sweden, Spain, and the United Kingdom, whereas pig feces and manure were more often positive in Spain than in Sweden (30% versus 1%). Most VRE were Enterococcus faecium carrying vanA, and computerized biochemical phenotyping of the isolates of different ecological origins showed a high degree of polyclonality. In conclusion, it seems that animal-associated VRE probably reflect the former use of avoparcin in animal production, whereas VRE in human-associated samples may be a result of antibiotic use in hospitals. Since there seems to be a reservoir of the resistance genes in all countries studied, precautions must be taken to limit the use of antibiotics and antibiotic-like feed additives.Enterococci are members of the normal intestinal microflora in humans and animals, and they are common in environments affected by animal and human fecal material. These organisms are not considered primary pathogens, but because of their ability to acquire high-level resistance to antimicrobial agents enterococci have emerged as nosocomial pathogens worldwide (30). Concern has especially been focused on enterococci that show high-level resistance to the glycopeptide antibiotic vancomycin (vancomycin-resistant enterococci [VRE]), which until recently has been the drug of last resort against multiresistant enterococci and against methicillin-resistant Staphylococcus aureus.In the United States, the incidence of bloodstream infection due to VRE increased from 0.4% in 1989 to 25.2% in 1999 (35), and between 15 and 24% of the hospitalized patients were reported to be colonized with VRE in 1998 (33). A later report indicated that 15% of all clinically relevant isolates of gram-positive cocci were VRE (17), whereas VRE of the VanA and VanB types have not been reported in animals so far. Thus, in the United States VRE are thought to have emerged and spread entirely as a result of the antibiotic use in hospitals. In Europe, infections caused by VRE remain a moderate problem in most countries. A European surveillance study found VRE in 7% of enterococcal isolates from blood cultures (13). On the other hand, healthy carriers of VRE in the community are relativ...

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Tungsten oxide is shown to be a very promising material for the fabrication of highly selective ammonia sensors. Films of WO 3 were deposited onto a silicon substrate by means of the drop-coating method. Then, the films were annealed in dry air at two different temperatures (300 and 400ЊC). X-ray photoelectron spectroscopy was used to investigate the composition of the films. Tungsten appeared both in WO 2 and WO 3 oxidation states, but the second state was clearly dominant. Scanning electron microscopy results showed that the oxide was amorphous or nanocrystalline. The WO 3 -based devices were sensitive to ammonia vapors when operated between 250 and 350ЊC. The optimal operating temperature for the highest sensitivity to ammonia was 300ЊC. Furthermore, when the devices were operated at 300ЊC, their sensitivity to other reducing species such as ethanol, methane, toluene, and water vapor was significantly lower, and this resulted in a high selectivity to ammonia. A model for the sensing mechanisms of the fabricated sensors is proposed.