Fachbereich Veterinärmedizin



    In vitro susceptibility of Staphylococcus aureus strains isolated from cows with subclinical mastitis to different antimicrobial agents (2012)

    Zeitschriftenartikel / wissenschaftlicher Beitrag
    El Behiry, Ayman
    Schlenker, Gerd
    Szabo, Istvan
    Rösler, Uwe (WE 10)
    Journal of veterinary science / The Korean Society of Veterinary Science; 13(2) — S. 153–161
    ISSN: 1229-845x
    URL (Volltext): http://edocs.fu-berlin.de/docs/receive/FUDOCS_document_000000019622
    DOI: 10.4142/jvs.2012.13.2.153
    Pubmed: 22705737
    Institut für Tier- und Umwelthygiene

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    Abstract / Zusammenfassung

    Sensitivity to commercial teat dips (nonoxinol-9 iodine complex and chlorhexidine digluconate) of 56 Staphylococcus (S.) aureus strains isolated from quarter milk samples of various German dairy herds treated with different teat dipping schemes was investigated in this study. The minimum inhibitory concentration was determined using a broth macrodilution method according to the German Veterinary Association guidelines. The main objective of the current study was to induce in vitro resistance induction of S. aureus to chemical disinfectants. Ten different strains were repeatedly passed ten times in growth media with sub-lethal concentrations of disinfectants. Nine strains showed a significant reduction in susceptibility to the nonoxinol-9 iodine complex but only one strain developed resistance to chlorhexidine digluconate. Stability of the acquired resistance was observed in all S. aureus strains adapted to the nonoxinol-9 iodine complex and chlorhexidine digluconate. In contrast, simultaneous resistance to different antibiotics was not observed in any of the ten investigated S. aureus strains. However, the isolates exhibited a high degree of resistance to penicillin G. Based on these results, resistance of S. aureus to chemical disinfectants may be more likely to develop if the chemicals are used at concentrations lower than that required for an optimal biocidal effect.