Current trends in Community-acquired methicillin resistant Staphylococcus aureus in Argentina

MOLLERACH M

Journal of Science, Humanities and Arts

International Academy of Sciences, Humanities and Arts

Lugar: Freiburg; Año: 2015 vol. 2

Community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) infections have become a major concern worldwide. Different from hospital-acquired MRSA, CA-MRSA usually is staphylococcal cassette chromosome (SCCmec) type IV, carries genes for Panton-Valentine leukocidin (PVL) and is susceptible to several non ß-lactam antibiotics. The epidemic of CA-MRSA is evolving. A specific clone that is initially propagating and causing CA-MRSA infectionscan be displaced by a more successful one. In Argentina, previous studies have identified sequence type 5 (ST5), SCCmec IV, spa type 311 as the predominant CA-MRSA clone causing infections and colonizing children.We conducted two prospective observational multicenter studies in adolescent and adult patients in Argentina. The specific aims were: a) to evaluate clinical features and genotype of strains in invasive CA-MRSA infections (Invasive CA-MRSA study), b) to establish the prevalence, clinical and molecular characteristics of CA-MRSA in patients with skin and skin structure infections (SSSI study).The SSSI study of CA-MRSA provided several findings. Firstly, CA-MRSA has become the most common cause of skin and soft tissue infections in our patient without healthcare contact.From the total of 311 patients enrolled with SSSI 70% had CA-MRSA. The occurrence of CA-MRSA as the predominant pathogen prompted an urgent change in the empirical therapy used to treat our community patients with SSSI. In addition, results from this study encouraged physicians to obtain cultures in patients with SSSI, most importantly in those areas where the prevalence of CA-MRSA or its antibiotic susceptibility was unknown. Second, SSSI caused by CA-MRSA have some characteristics that can be easily detected at the initial clinicalevaluation. In our community population CA-MRSA is more common in patients < 50 years old and presenting with purulent lesion such as abscesses or furuncles. Third, consistent with the finding of ST-30 SCCmec IV, PVL+ spa t019 among patients with invasive CA-MRSA infections in Argentina, we revealed the predominance of the same clone among our patients suffering SSSI from the community. This clone which was previously considered as an uncommonclone in Argentina appears to have displaced the previously predominant clone (ST5, SCCmec IV, PVL+).