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Characterization of Multi-resistent Pseudomonias Aerigunosa in clinical and municipal wastewater systems of two different cities

Characterization of Multi-resistent Pseudomonias Aerigunosa in clinical and municipal wastewater systems of two different cities
chair:

Schwartz, T. / Schön-Hölz, K. / Ott, E. / Kohnen, W. (2011)

place:

FEMS 2011, Genf, Schweiz, 26.-30. Juni, 2011

Date: 2011

Schwartz, T. / Schön-Hölz, K. / Ott, E. / Kohnen, W. (2011): „Characterization of Multi-resistent Pseudomonias Aerigunosa in clinical and municipal wastewater systems of two different cities“. In: FEMS 2011, Genf, Schweiz, 26.-30. Juni, 2011

Abstract

Background: As antibiotic resistance is commonly found in wastewater systems, its persistence seems to be obvious. The factors determining the persistence of antibiotic resistance are largely unknown. Antibiotics or substances with a likewise mode of action may provide selection advantages for resistant bacteria.

Objective: Pseudomonas aeruginosa is a clinically important, opportunistic pathogen which exhibits high intrinsic resistance to numerous antimicrobial agents. The persistence of multiresistant Pseudomonas aeruginosa carrying up to seven acquired therapeutically relevant antibiotic resistance mechanisms was studied in clinical and downstream municipal wastewater systems of two German cities.

Method: Such multi-resistant P. aeruginosa may be enriched by clinical as well as municipal wastewaters. Agar diffusion testing and molecular biology confirmed their multi-resistant phenotypes. Pulsed Field Gel Electrophoresis (PFGE) genotyping resulted in different groups of P. aeruginosa isolates depending on sampling points and numbers of resistances. It was shown previously that the overexpression of efflux systems in clinical isolates from patients can contribute to multi-resistance against various antibiotics. Thus, the expression of four important efflux pump systems (MexA-MexB-OprM, MexC-MexD-OprJ, MexE-MexF-OprN, and MexXMexY- OprM) was analysed in multi-resistant P. aeruginosa as well as in antibiotic-susceptible isolates from different wastewater systems.

Conclusions: The highest expression rates were detected in antibiotic-susceptible P. aeruginosa strains. No overexpression of the efflux pump operons was observed, indicating that multi-resistances of the isolated P. aeruginosa strains were based on antibiotic-specific mechanisms.