Salmonella Typhi Osteomyelitis of the Ulnar Diaphysis in an Immunocompetent Adult: A Case Report.

Salmonella Typhi is an uncommon cause of chronic osteomyelitis and may present diagnostic challenges, particularly in patients without identifiable predisposing factors. We report the case of a 22-year-old immunocompetent man who presented with progressive pain and swelling over the middle third of the left forearm for four months. Laboratory investigations revealed normal inflammatory markers, including an erythrocyte sedimentation rate of 2 mm/hr and a C-reactive protein level of <0.50 mg/dL. Plain radiographs demonstrated cortical thickening, periosteal reaction, and sequestrum formation involving the ulnar shaft, while MRI showed chronic intramedullary osteomyelitis with cortical cloaca formation and an intracortical abscess. The patient underwent surgical sequestrectomy and debridement. Intraoperative bone cultures grew S. Typhi resistant to ciprofloxacin, levofloxacin, and azithromycin but sensitive to ceftriaxone and cotrimoxazole. Histopathological examination confirmed chronic osteomyelitis. Treatment with intravenous ceftriaxone followed by oral cotrimoxazole resulted in complete clinical and radiological recovery without recurrence. This case emphasizes the importance of obtaining tissue cultures in chronic osteomyelitis to identify unusual pathogens and guide appropriate antimicrobial therapy. Salmonella Typhi should be considered among the potential etiological agents of chronic osteomyelitis, even in the absence of recognized risk factors.