Prevalence of Staphylococcus aureus and mec-A Cassette in the Throat of Non-Hospitalized Individuals Randomly Selected in Central Italy

Methicillin-resistant Staphylococcus aureus (MRSA) is a cause of life-threatening infections that are difficult to treat because of resistance to several antibiotics. Most documented MRSA infections are acquired nosocomially or among community with frequent contact with health facilities. However, an increasing attention to community acquired MRSA strains appears justified. A population of Central Italy was investigated for the presence of S. aureus and for the methicillin-resistance determinant mec-A gene. Exclusion was due to systemic diseases, pathologies or therapies inducing systemic immunosuppression, facial trauma or poor oral hygiene. Throat swabs obtained from 861 randomly selected participants were tested for the presence of DNA sequences of S. aureus and the mec-A gene by real-time PCR. The DNA of S. aureus was detected in 199 specimens (23.1%), while the mec-A gene was detected in 27 samples (3.1%). The prevalence of patients carrying methicillin-resistant strains was higher in younger and older strata. The prevalence of mec-A among S. aureus positive samples was 7.5%. Our data confirm that S. aureus and methicillin-resistant strains are common in the throat of the general population of Central Italy. Although the PCR methods used in this study are different from traditional culture-based approaches, the observed prevalence was consistent to those observed in Italians and other populations. Considering that carriers have a higher risk to develop post surgically life-threatening infections, it is worth evaluating a preventive approach based on rapid PCR screening of incoming patients to reduce the risk of developing health-care-associated infections.