Antibiotic-resistant Pseudomonas aeruginosa from hospital wastewater and superficial water: Are they genetically related?

Many studies have reported the presence of antibiotic-resistant Pseudomonas aeruginosa in environmental samples such as hospital wastewater and surface water. The present study evaluated the contribution of untreated hospital wastewater to the dissemination of resistant P. aeruginosa strains in aquatic environments, through the analysis of their antibiotic susceptibility profile and genetic similarity. Wastewater samples were collected from two hospitals located in Rio Grande do Sul, RS, Brazil. Superficial water samples were collected from water bodies that received this wastewater discharge. The antibiotic susceptibility profiles of the strains were determined using the disk-diffusion technique and their genotyping was done by amplification of the Enterobacterial Repetitive Intergenic Consensus sequences (ERIC-PCR). The antibiotic resistance was higher among the hospital wastewater strains and the multiresistant phenotype was also observed only among these strains. The ERIC-PCR profiles did not reveal any genetic similarity among the P. aeruginosa strains from the wastewater and superficial water samples. On the contrary, they showed that genetically distinct populations were established in these different environments and probably that some other contamination source could be contributing to the presence of resistant strains in these water bodies.     

Passivsammler für die zeitintegrierte chemische und toxikologische Überwachung des Schadstoffgehaltes in Grund- und Oberflächenwasser

The availability of high-quality water plays a pivotal role for the protection of the ecosystem and the quality of human life. An important step in assessing ground and surface water quality is sampling. The time-integrated accumulation of environmental contaminants by passive sampling is an attractive alternative to conventional snap-shot sampling. Thein situ accumulation during passive sampling allows the detection of even lowconcentrated contaminants and reduces cost and time for continuous monitoring. Passive sampling provides information on the whole sampling period and avoids the transport and storage of large sample volumes. Matrix effects are reduced due to the selective enrichment. Various passive samplers have been developed for sampling in aqueous media. Early developments used water filled dialysis tubes for the sampling of trace elements. Later on, solvent filled devices and triolein-filled semipermeable membrane devices (SPMDs) were deployed. More recent developments use a solid rather than a liquid sorbent as the receiving phase. Examples of this are the solid phase microextraction (SPME) and the membrane enclosed sorptive coating (MESCO). In addition to comprising miniature devices, SPMEs as well as MESCO are thermodesorbable and, as such, no longer require solvent extraction. Conventionally the sampled contaminants are removed from the passive sampling devices by solvent extraction or thermodesorption in order to be analyzed chemically. For an in-depth analysis of sampled analytes, however, it would be advantageous to modify passive sampling such that sampled contaminants can also be analyzed biologically. Thus, it is our goal to construct a passive sampling device that serves both as a sampling device as well as an exposure chamber for toxicity testing. The principle underlying this technology is the bioavailability of sorbed contaminants, thereby eliminating the need for solvent extraction.     

Die Flavonoidausstattung von Streptocarpusblüten

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