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968 Occurence of Vancomycin-Resistant Enterococcus faecium (VREF) in patient isolates and aquatic environment during a period between 2004-2009

Sunday, March 21, 2010
Grand Hall (Hyatt Regency Atlanta)
Claudia Böhme , University Medical Center of the Johannes Gutenberg University, Mainz, Germany
Wolfgang Kohnen , University Medical Center of the Johannes Gutenberg University, Mainz, Germany
Katja Schön-Hölz , University Medical Center of the Johannes Gutenberg University, Mainz, Germany
Thomas Schwartz , Institute of Functional Interfaces, Institute of Technology Karlsruhe, Karlsruhe, Germany
Ursula Obst , Institute of Functional Interfaces, Institute of Technology Karlsruhe, Karlsruhe, Germany
Bernd Jansen , University Medical Center of the Johannes Gutenberg University, Mainz, Germany
Background: The increase of antibiotic resistant bacteria and the resulting difficulties in the therapy of infections is a growing problem. As our findings of recent studies on the occurrence of VREF in the aquatic environment of a German hospital during an outbreak caused by two different genotypes of VREF in a hematology oncology department showed, hospitals are serving as a source of enrichment and contamination of the environment by VREF along the aquatic pathway of waste water to surface water.

Objective: To analyze the distribution of VREF in the aquatic environment during a non-outbreak situation we examined the occurrence, antibiotic resistance pattern and molecular diversity of VREF in patients, wastewater of the hospital and residential areas as well as water in sewage plants and in surface waters of the receiving rivers.

Methods: During a time period between 2004 until 2009 water samples were collected, VREF were isolated by selective media and tested against a panel of different antibiotics. The molecular-biological analysis of VREF isolates was performed by pulsed-field gel electrophoresis (PFGE). For genotyping, a dendrogram with 286 different PFGE-patterns from VREF (comprises 106 PFGE-patterns from patients and 181 from environmental water samples) was created with GelCompar II.

Results: Although the rates of enterococci and VREF were reduced in the sewage plant, VREF were recovered from 75 - 100 % of the untreated wastewater samples, from 87.5% of the treated wastewater samples and from 31.8 – 63.6 % of the surface water samples indicating a high VREF prevalence in the aquatic environment. Regarding the resistance against the antibiotics tested, no difference between isolates from patients and from the environment was noticed.

PFGE-analysis resulted in a high diversity of different VREF genotypes. At a similarity level of > 80%, isolates were regarded as clonally related resulting in 51 genotype-groups with two or more PFGE-patterns.

Conclusions: The main result of our study is that the group with the numerically highest number of PFGE-patterns, which also includes the outbreak strains from 2005, is still predominant up to now in patients and in the aquatic environment. In contrast, other genotype-groups have disappeared in patients and in the environment over time.