Occurrence and enterotoxic characterisation of methicillin-resistant Staphylococcus aureus from raw milk in southern Italy

Abstract number: 1733_1092

Dambrosio A., La Salandra G., Corrente M., Quaglia N.C., Lorusso V., Germinario G.L., Mula G., Normanno G., Celano G.V.

Objectives: Methicillin-resistant Staphylococcus aureus (MRSA) strains are a global health concern. Infection could be associated with the ingestion of contaminated foods. In addition the ingestion of food contaminated by enterotoxins (SEs) synthesized by S. aureus is responsible of one of the most common foodborne intoxication. Since S. aureus is often involved in subclinical mastitis of ruminants, milk may results contaminated. In fact, the dairy products are frequently related to cases of Staphylococcal Food Poisoning (SFP), expecially in areas characterised by a high level of consumption of dairy products. Consequently an active microbiological surveillance of milk and dairy products is desirable in order to control the risk of MRSA foodborne infections and SFP and to allow the improvement of the public health standards. In this work are reported the results of a survey conducted on the occurrence and enterotoxic characterisation of MRSA in bulk milk from Apulia region (Southern Italy).

Methods: In the present study are reported the results obtained from the investigation of 560 bulk milk samples produced in Apulia region in order to detect MRSA strains. The S. aureus isolates (one per positive sample) were characterised by detecting the mecA gene by polymerase chain reaction, and the production of type A to D staphylococcal enterotoxins (SEs), using the reverse passive latex agglutination method.

Results: Of the 560 samples 90 (16%) were contaminated with S. aureus and among the positive samples one showed the presence of a MRSA (mecA positive) strain. The MRSA strain resulted able to produce staphylococcal enterotoxin C plus enterotoxin D (SEC plus SED).

Conclusions: Despite its low prevalence in the samples analysed, the presence of MRSA constitutes a serious health hazard, especially for immunocompromised individuals. Such a finding calls for better hygiene in milk production along the food-chain, especially at the primary production level. The presence of antibiotic resistance in potentially harmful bacteria in foods of animal origin warrants further investigations into the role of antibiotics when they are used for therapeutic purposes or as growth promoters in food-producing animals.

Session Details

Date: 31/03/2007
Time: 00:00-00:00
Session name: European Society of Clinical Microbiology and Infectious Diseases
Location: ICC, Munich, Germany
Presentation type:
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