Moraxella osloensis Isolated from the Intraoperative Field After Reverse Total Shoulder Arthroplasty

Area of Science:

• Microbiology
• Orthopedic Surgery
• Infectious Disease

Background:

• Moraxella osloensis is a skin bacterium with an unclear role in surgical site contamination.
• Its pathogenic potential in shoulder arthroplasty requires further investigation.

Purpose of the Study:

• To investigate the presence and characteristics of Moraxella osloensis in periprosthetic tissues after shoulder arthroplasty.
• To assess the clinical significance and virulence factors of M. osloensis in this context.

Main Methods:

• Recovery and characterization of M. osloensis from intraoperative periprosthetic tissue samples.
• Antimicrobial susceptibility testing and beta-lactamase production assessment.
• Biofilm formation assays.
• Clinical follow-up of patients for postoperative infections and wound healing.

Main Results:

• M. osloensis was recovered from five patients, with low colony counts and uniform susceptibility to tested antibiotics.
• No beta-lactamase production was observed in the isolates.
• Biofilm formation was detected in two of the five isolates.
• No postoperative infections occurred; one patient had a transient wound-healing delay.

Conclusions:

• Moraxella osloensis may be an endogenous contaminant in the shoulder arthroplasty operative field.
• Despite biofilm potential, M. osloensis appears to have limited clinical impact in this setting.
• Continued surveillance and careful interpretation of M. osloensis isolates are recommended.