Case Report of Klebsiella Aerogenes Infection After Synthetic Bone Graft: Challenges From Diagnosis to Treatment

Musculoskeletal infections, including osteomyelitis, have increased in recent decades. Accurate diagnosis and management are challenging and require close collaboration between infectious disease specialists and surgical teams. The combination of adequate surgical debridement, removal of fixation materials when feasible, systemic antimicrobials, and local use of antibiotics or biomaterials is essential for effective biofilm treatment, better outcomes, and rational antimicrobial use. A 36-year-old white man with idiopathic osteonecrosis of the left femoral head underwent core decompression and grafting with calcium phosphate. One week after discharge, he developed wound dehiscence, treated with local care and oral antibiotics, with initial healing. Eight weeks post-surgery, he returned with pain, edema, erythema, and fistula at the site, graft extrusion, and need for surgical debridement. Cultures from five samples grew Klebsiella aerogenes susceptible to multiple antibiotics, and histopathology confirmed chronic osteomyelitis. He received 8 weeks of intravenous antibiotics and 2 weeks of oral trimethoprim-sulfamethoxazole. Three weeks after completing therapy, the wound reopened with suture and graft fragment extrusion, no systemic signs of infection, but persistent drainage, especially after exertion. Imaging showed a fistulous tract between muscle and skin with a 7 mL collection. A two-stage surgical approach was indicated. In the first stage, vancomycin and meropenem were started, with debridement, complete graft removal, irrigation, sampling, and placement of PMMA cement loaded with vancomycin and gentamicin. One week later, with cultures confirming K. aerogenes susceptible to meropenem and gentamicin, the second stage was performed: cement removal and filling of the bone defect with 10 cc of S53P4 bioactive glass (Bonalive®). The patient completed 6 weeks of targeted antibiotic therapy and, at 180 days, remained infection-free with complete wound healing. Proper management of musculoskeletal infections requires strategies beyond systemic antibiotic therapy alone. A specialized multidisciplinary team is essential for early diagnosis, rational antibiotic use, and more effective therapeutic resources, ensuring better clinical outcomes.