Propionibacterium acnes Susceptibility and Correlation with Hemolytic Phenotype

Area of Science:

• Microbiology
• Infectious Diseases
• Surgical Infections

Background:

• Invasive infections caused by Propionibacterium acnes (P. acnes) are rising, especially post-shoulder replacement surgery.
• Increased P. acnes diagnoses are linked to more shoulder procedures and enhanced anaerobic culturing.
• Optimal management strategies for P. acnes infections remain debated.

Purpose of the Study:

• To evaluate the antimicrobial susceptibility of P. acnes strains isolated from sterile body sites.
• To investigate potential correlations between phenotypic characteristics and antibiotic resistance in P. acnes.

Main Methods:

• Antimicrobial susceptibility testing was performed on 106 P. acnes isolates using Etest gradient strips.
• Isolates were collected from sterile body sites between 2012 and 2015.
• Hemolytic phenotype was assessed on Brucella Blood Agar.

Main Results:

• P. acnes demonstrated high susceptibility to penicillins and first-generation cephalosporins.
• A significant association was observed between a hemolytic phenotype and resistance to clindamycin.
• The study identified specific antibiotic sensitivities and resistance markers.

Conclusions:

• Routine antimicrobial susceptibility testing for P. acnes is recommended beyond research settings.
• Integrating susceptibility testing into routine microbiology can improve patient care.
• Further investigation is needed to clarify the hemolysis-clindamycin resistance relationship.