Calcium sulphate mixed with antibiotics does not decrease efficacy against Cutibacterium acnes (formerly Propionibacterium acnes), in vitro study.

BACKGROUND

This study explored the in vitro efficacy of antibiotics mixed with calcium sulfate (ACS) against Cutibacterium acnes (C. acnes).

METHODS

C. acnes isolates from orthopaedic infection sites were tested for antimicrobial susceptibility with ACS. Minimal inhibitory concentrations (MIC) were determined with a gradient diffusion method (Etest® strips).

RESULTS

When tested with Etest®, all 22 isolates were susceptible to penicillin, ceftriaxone, vancomycin, and two were resistant to clindamycin (MICs of 4 and 8 mg/L). Penicillin and rifampin had the largest inhibition zone diameters.

CONCLUSIONS

Antibiotics retained activity against C. acnes when mixed with calcium sulfate.