High prevalence of clindamycin resistance in Staphylococcus aureus blood culture isolates in São Paulo, Brazil

BACKGROUND: Clindamycin has become an important antimicrobial option for the treatment of Staphylococcus aureus. However, little is known about the current patterns of clindamycin-susceptibility in S. aureus invasive isolates, both in our country and in other developing countries in the world. AIMS: The aim of this study was to determine the prevalence of constitutive and inducible clindamycin resistance in methicillin-susceptible S. aureus (MSSA) and methicillin-resistant S. aureus (MRSA) blood culture isolates in São Paulo, Brazil. MATERIALS AND METHODS: From July 2011 to June 2012, all S. aureus isolates from blood cultures collected at our hospital were included in the study. Antimicrobial susceptibility testing was performed according to recommendations of the Clinical and Laboratory Standards Institute. RESULTS: Total prevalence of clindamycin resistance was 68%, including 7.2% with inducible resistance. In MRSA resistance rate was 90.8% whereas in MSSA the rate was 32.7%. CONCLUSIONS: Our high prevalence of clindamycin resistance highlights the importance of performing D-test in a routine base, as well of maintaining continued surveillance for the prevalence of clindamycin resistance.