Invasive group B streptococcal disease in an orthopaedic unit

Area of Science:

• Orthopaedic Surgery
• Infectious Diseases
• Microbiology

Background:

• Invasive group B streptococcus (GBS) is an emerging pathogen in orthopaedic infections.
• Risk factors include advanced age, diabetes mellitus, and immune deficiency.
• GBS can manifest as native or periprosthetic joint sepsis, osteomyelitis, and soft tissue infections.

Purpose of the Study:

• To describe the epidemiology and clinical outcomes of GBS infections in a large cohort of orthopaedic patients.
• To determine the incidence of GBS infections in relation to orthopaedic procedures and patient demographics.
• To assess the antimicrobial susceptibility patterns of GBS isolates.

Main Methods:

• Retrospective analysis of patients with GBS identified in deep tissue or aspirate samples over three years.
• Inclusion criteria: all patients presenting to the institution with GBS.
• Data collected included patient demographics, infection type, treatment, and outcomes.

Main Results:

• Seventeen cases of GBS infection were identified, with an annual incidence of 0.69 per 100,000 adults.
• Eight cases (0.15% of joint replacements) were associated with prosthetic joints.
• Six isolates showed intermediate resistance to macrolides; all were susceptible to benzylpenicillin. Sixteen patients required surgical debridement, and two underwent amputation.

Conclusions:

• Group B streptococcus is a significant cause of orthopaedic infections, particularly in patients with specific risk factors.
• Awareness of GBS as a causative agent is essential for timely diagnosis and management.
• Effective treatment strategies, including surgical intervention, are critical for favorable outcomes.