When MRSA Misleads: Tuberculous Osteomyelitis of the Anterior Pelvic Bones.

INTRODUCTION: Osteomyelitis of the pubic symphysis is rare, representing less than one percent of all osteomyelitis cases, and is frequently misdiagnosed as genitourinary pathology owing to overlapping symptoms and anatomical proximity. Tuberculous involvement at this site is exceptional, and concurrent infection with methicillin-resistant Staphylococcus aureus (MRSA) remains infrequently documented. This case contributes to orthopedic literature by demonstrating how reliance on blood and pus cultures alone can delay recognition of occult mycobacterial disease in culture-discordant pelvic osteomyelitis, reinforcing the indispensable role of surgical biopsy and histopathology in guiding combined antimycobacterial and antistaphylococcal therapy.

CASE REPORT: A 40-year-old South-Asian woman with hypothyroidism and recurrent urinary tract infections presented with 2 weeks of progressive suprapubic pain radiating to both lower limbs and high-grade fever. Examination revealed fever, suprapubic tenderness, and restricted bilateral hip movements. Laboratories showed neutrophilic leukocytosis and elevated C-reactive protein. Blood culture grew MRSA; urine and ultrasound-guided prepubic pus cultures were sterile. Magnetic resonance imaging confirmed bilateral pubic bone osteomyelitis, superior rami involvement, abscesses, and myositis. Symptoms persisted despite intravenous teicoplanin, prompting surgical debridement. Curetted bone histopathology demonstrated necrotizing granulomatous inflammation with acid-fast bacilli, establishing tuberculous osteomyelitis complicated by secondary MRSA bacteremia.

CONCLUSION: Clinicians managing non-resolving pubic osteomyelitis must pursue tissue diagnosis for mycobacterial infection, even when pyogenic pathogens are isolated, and pus is culture-negative. Prompt initiation of anti-tubercular therapy alongside targeted antibiotics yields rapid recovery. This report advances orthopedic infectious disease practice by providing a reproducible diagnostic algorithm for polymicrobial drug-resistant pelvic sepsis, with immediate relevance to orthopedics, infectious diseases, urology, and gynecology in tuberculosis-endemic regions.