Can interchangeability of lincosamides be assumed in clinical practice? Comparative MICs of clindamycin and lincomycin for Streptococcus pyogenes, Streptococcus agalactiae and Staphylococcus aureus

摘要

Recently in Australia, prescribing patterns for lincosamides have changed. Parenteral lincomycin use now exceeds parenteral clindamycin use in hospitals, including intensive care units. The reasons pertain to availability, cost and the recommendations of the national antibiotic guidelines. The Australian therapeutic guidelines present lincomycin and clindamycin as equivalent treatments for serious infections due to Streptococcus pyogenes, Streptococcus agalactiae and Stophylococcus aureus. As there are no CLSI or EUCAST breakpoints for lincomycin, Australian clinicians infer lincomycin susceptibility from clindamycin susceptibility. Challenging the validity of this approach are reports of 'L-phenotype' staphylococci and beta-haemolytic streptococci that test clindamycin susceptible but lincomycin resistant. L-phenotype staphylococci and streptococci of both animal and human origin have been identified, mediated by u(A), lnu{B), lnu[C), lnu[D) and u(F). The frequency of L-phenotype isolates occurring in Australia is unknown. We compared the MICs of lincomycin and clindamycin for local clinical isolates of S. pyogenes, S. agalactiae and S. aureus to determine whether L-type susceptibility patterns were present, and to compare MIC values. The data will be used as an evidence base for local policies regarding lincosamide choice. Ninety S. pyogenes, 45 S. agalactiae and 100 S. aureus isolates (50 methicillin susceptible and 50 methicillin resistant) were tested for MICs of clindamycin and lincomycin by the CLSI agar dilution method.