Methods: Species identification of S. aureus and presence of mecA were performed by PCR. We determined MICs to common anti-MRSA antibiotics and performed screening for VISA phenotype. Molecular characterization included detection of lukSF-PV and SCCmec typing. PFGE and MLST were performed in selected MRSA isolates with susceptibility patterns typical of the Chilean (ST5-MRSA-I) and USA300-LV (ST8-MRSA-IV) lineages.
Results: A total of 665 S. aureus isolates were prospectively recovered from 592 patients. A high frequency of methicillin resistance (> 40%) was observed in all countries (62%, 55%, 44% and 40% in BRA, PER, CHI and ARG, respectively). Decreased susceptibility to VAN was not observed and VAN MIC90 was 1 µg/ml. In PER and CHI, the overwhelming majority of isolates (89%) belonged to the Chilean/Cordobes clone (CC5) with susceptibility patterns typical of this lineage (Resistance to ß-Lactams, MLSB-type, quinolones and aminoglycosides). The New York/Japan clone (ST5-MRSA-II) was predominant in Brazil, replacing the prevalent hospital-associated Brazilian (ST239-MRSA-III) lineage. Most Argentinian MRSA isolates exhibiting a CA (ST5-IV) pattern, previously described in this country.
Conclusion: A variety of MRSA genetic lineages are circulating in Latin America with geographic clustering and clonal replacement. Dissemination of the CA-USA300-LV has not occurred beyond the northern region of the subcontinent.
R. Rios, None
A. Echeverri, None
S. Rincon, None
J. M. Munita, Pfizer: Grant Investigator , Research grant .
T. Tran, None
D. Panesso, None
C. Arias, Merck & Co., Inc.: Grant Investigator , Research support . MeMed: Grant Investigator , Research support . Allergan: Grant Investigator , Research support .
L. Diaz, None
See more of: Poster Abstract Session