Primary Sternal Osteomyelitis due to Ralstonia pickettii in a Haemodialysis Patient: A Case Report

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Sternal osteomyelitis is a rare infection of the sternum and accounts for less than 1% of all osteomyelitis cases. It is most frequently observed following chest trauma or as a complication of cardiac surgery. However, cases occurring in the absence of these predisposing factors, referred to as Primary Sternal Osteomyelitis (PSO), are exceedingly uncommon. Ralstonia pickettii is an aerobic, non fermenting Gram-negative bacillus increasingly recognised as an opportunistic healthcare-associated pathogen, particularly among immunocompromised individuals. Although it is commonly associated with contaminated hospital fluids and medical devices causing bloodstream infections, tissue infections due to this organism remain exceptionally uncommon. A case of a 54-year-old male with end-stage renal disease on maintenance haemodialysis, diabetes mellitus, and hypertension, presenting with chest pain and anterior chest wall swelling, was described. During hospitalisation, the patient developed fever, and imaging demonstrated a destructive lesion of the sternum suggestive of osteomyelitis. Blood cultures and aspirated pus from the sternal swelling yielded pure growth of Ralstonia pickettii. The isolate was identified using the VITEK 2 automated identification system and subsequently confirmed by 16S rRNA gene sequencing. Antimicrobial susceptibility testing demonstrated susceptibility to ciprofloxacin, levofloxacin, and trimethoprim-sulfamethoxazole, while showing resistance to several other antimicrobial agents. Based on the susceptibility profile, the patient was treated with ciprofloxacin, resulting in significant clinical improvement. This case highlights the rare occurrence of PSO caused by Ralstonia pickettii in an immunocompromised patient. Accurate identification using automated and molecular methods, together with antimicrobial susceptibility-guided therapy, is essential for favourable clinical outcomes. Reporting such uncommon presentations expands the existing literature and may facilitate early recognition and appropriate management of similar infections. This report emphasises the diagnostic challenges, limited therapeutic guidance and importance of targeted antimicrobial therapy in managing Ralstonia infections.