Calcium sulphate mixed with antibiotics does not decrease efficacy against Cutibacterium acnes (formerly...

Area of Science:

• Orthopaedic Surgery
• Infectious Diseases
• Microbiology

Background:

• Cutibacterium acnes (C. acnes) is a common pathogen in orthopaedic infections.
• Antibiotic-loaded calcium sulfate (ACS) is a potential treatment strategy.
• Understanding the in vitro efficacy of ACS against C. acnes is crucial.

Purpose of the Study:

• To evaluate the in vitro antimicrobial activity of antibiotics combined with calcium sulfate (ACS) against Cutibacterium acnes (C. acnes).

Main Methods:

• Antimicrobial susceptibility testing of C. acnes isolates from orthopaedic infections using ACS.
• Determination of Minimal Inhibitory Concentrations (MICs) via gradient diffusion method (Etest® strips).

Main Results:

• All 22 C. acnes isolates demonstrated susceptibility to penicillin, ceftriaxone, and vancomycin.
• Two isolates exhibited resistance to clindamycin with MICs of 4 and 8 mg/L.
• Penicillin and rifampin yielded the largest inhibition zone diameters, indicating significant activity.

Conclusions:

• Antibiotics incorporated into calcium sulfate retain their antimicrobial activity against C. acnes.
• ACS represents a viable option for delivering antibiotics directly to infection sites.
• Further in vivo studies are warranted to confirm clinical efficacy.