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Are susceptibility testing results for clindamycin from microdilution automated systems reliable for therapeutic decisions?

Abstract number: 1734_120

Treviño M., Moldes L., Garcia-Riestra C., Gómez-Rial M., Jorge M., Regueiro B.

Objectives: Clindamycin has long been an option for treating both, methicillin-susceptible (MSSA) and methicillin-resistant (MRSA) S. aureus infections, particlularly skin and soft tissue infections. Missidentification of inducible MLSB resistance may lead to clinical failure of clindamycin therapy. We studied the prevalence of MLSBi in community- and hospital-associated S. aureus isolates, including MRSA and MSSA, at our institution.

Methods: We prospectively collected sequential nonduplicate S. aureus isolates exhibiting erythromycin resistance and clidamycin susceptibility, as determined by broth microdilution using an autommated system (VITEK System, boiMérieux, France) from April to November 2006. Testing for MLSBi was accomplished by the agar diffusion (D test) method in accordance with the recommendations of the Clinical and Laboratory Standards Institute (CLSI).

Results: Among 63 S. aureus isolates, the overall prevalence of MLSBi was 77.8%, with 75% of MRSA and % 78 of MSSA isolates exhibiting MLSBi. CA-MRSA was not found. Prevalence of MLSBi hospital associated MRSA was 83.3%. CA-MSSA has a lower prevalence of MLSBi than hospital associated MSSA (72.4% versus 83.3%).

Conclusions: Susceptibility results for clindamycin using methods that do not detect induced resistance are not reliable in order to avoid clinical failures in patient who receive clindamycin for S. aureus infections with MLSBi.

Session Details

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