Agricultural and Municipal Waste Water as a Source of Antibiotic-Resistant Enterococci

Cupáková, ·. , J . Luká‰ová: Agricultural and Municipal Waste Water as a Source of Antibiotic-Resistant Enterococci. Acta Vet. Brno 2003, 72: 123-129. The occurrence of enterococci in different waste waters from two cattle farms in south and north Moravia and sewage treatment plant of the University of Veterinary and Pharmaceutical Sciences Brno, Czech Republic was investigated. Resistance and/or sensitivity of selected isolates was tested to various antibiotics. The samples were collected in the course of two years (1999-2000). The total counts of enterococci varied from 103 to 105 colony-forming units (CFU) per ml. Among 100 isolated strains 60 strains were identified as Enterococcus faecalis, 10 as Ent. durans as well as Ent. hirae, 8 strains were allotted to Ent. faecium, 5 to Ent. mundtii, 3 to Ent. gallinarum, 2 to Ent. casseliflavus, one strain was identified as Enterococcus spp. and one strain was not specified as enterococcus. The susceptibility to antibiotics was tested by both, the agar disk diffusion method and the microdilution method. The majority of enterococci (95%) was resistant to more than one antibiotic tested, especially to clindamycin, penicillin, cephalotin, ofloxacin and tetracycline. No vancomycin-resistant strain was found. Our results confirm that agricultural and municipal waste waters might be an important source of antibiotic-resistant enterococci. Enterococci, waste water, silage, liquid manure, cattle, antibiotic-resistance Enterococci are a part of the common microflora in the gastrointestinal tract of warmblooded animals and birds. In addition they can occur in soil, surface or waste waters, on plants and vegetables (Franz et al. 1999). Enterococci are now considered as the third most common pathogens causing nosocomial infections and “superinfections” in hospitalized patients, accounting for nearly 12% of these infections (Linden et al. 1999). The most common enterococci-associated infections are infections of the urinary tract, bacteremia, endocarditis, intra-abdominal and pelvic infections. The very consequential ones are neonate meningitis and bacteremia and central nervous system infections in adults (Murray 1990; Franz et al. 1999). Vancomycin-resistant enterococci (VRE) represent a serious problem at present. They are usually isolated from environment, waste waters, animals, foods of animal origin. They still represent the worldwide problem for hospitalized patients, where the glycopeptide antibiotics vancomycin and teicoplanin are used in the therapy of several infections caused by Gram-positive bacteria (Klare et al. 1993; Borgen et al. 2001). The emergence of VRE in Europe is attached to the long-time use of the glycopeptide antibiotic avoparcin as a growth promoter for farm animals with the possibility of inducing cross-resistance to vancomycin. In 1997 it was banned in EU (Grosso et al. 2000). Many studies indicate food animals as reservoirs of resistant enterococci which might be transmitted to humans through the food chain and represent a potential risk for the consumers (Bates et al. 1994; Bager et al. 1997; Klein et al. 1998; Grosso et al. 2000). The aim of this study was to investigate the occurrence of enterococci in different kinds of agricultural and municipal waste waters and to test their sensitivity to selected antimicrobial agents. ACTA VET. BRNO 2003, 72: 123–129 Address for correspondence: MVDr. ·árka Cupáková Department of Milk Hygiene and Technology University of Veterinary and Pharmaceutical Sciences Brno Palackého 1-3, 612 42 Brno, Czech Republic Phone: +420 5 4156 2593 E-mail: [email protected] http://www.vfu.cz/acta-vet/actavet.htm