Characterization of Methicillin-resistant Staphylococcus aureus Isolates from Food and Food Products of Poultry Origin in Germany

During a survey of fresh chicken and turkey meat as well as chicken and turkey meat products for the presence of methicillin-resistant Staphylococcus aureus (MRSA) isolates in Germany, 32 (37.2%) of 86 samples were MRSA-positive. Twenty-eight of these MRSA isolates belonged to the clonal complex (CC) 398 which is widespread among food-producing animals. These CC398 isolates carried SCCmec elements of types IV or V, exhibited spa types t011, t034, t899, t2346 or t6574 and either the known dru types dt2b, dt6j, dt10a, dt10q, dt11a, dt11v, dt11ab or the novel dru types dt6m, dt10as, dt10at. In addition, two MRSA ST9 isolates with a type IV SCCmec cassette, spa type t1430 and dru type dt10a as well as single MRSA ST5 and ST1791 isolates with a type III SCCmec cassette, spa type t002 and dru type dt9v were identified. All but two isolates were classified as multiresistant. A wide variety of resistance pheno- and genotypes were detected. All isolates were negative for the major virulence factors such as Panton-Valentine leukocidin, toxic shock syndrome toxin 1 or exfoliative toxins. In contrast to the MRSA CC398 isolates, the four ST9, ST5 or ST1791 isolates harbored the ecg gene cluster for enterotoxin G, I, M, N, O and U genes. Although the relevance of contamination of fresh poultry meat or poultry products with MRSA is currently unclear, the presence of multiresistant and - in part enterotoxinogenic - MRSA emphasizes the need of further studies to elucidate possible health hazards for consumers