Antibiogram profiles and efficacy of antibiotic regimens of bacterial isolates from chronic osteomyelitis of the appendicular skeleton: A developing-world perspective

Abstract

Background. Empirical antibiotic strategies in the treatment of chronic osteomyelitis should ideally be based on local microbiological antibiograms. Objectives. To review the antibiogram profiles of bacterial isolates of patients undergoing surgical treatment for chronic osteomyelitis and identify the most appropriate empirical antibiotic strategy. Methods. A retrospective review of clinical records and microbial culture reports was performed for all patients who underwent treatment for chronic osteomyelitis at two orthopaedic units in Western Cape Province, South Africa, between March 2016 and December 2019. Reported antibiotic susceptibility data were used to predict the potential efficacy of different empirical antibiotic regimens, according to underlying aetiology (fracture related, contiguous, haematogenous). Results. Two hundred patients with chronic osteomyelitis of the appendicular skeleton underwent surgical management. Antibiogram profiles for 218 organisms, isolated from 169 patients, were evaluated. Staphylococcus aureus (41%) and Enterobacterales (30%) were the most common organisms isolated. The combinations of meropenem plus vancomycin, and piperacillin-tazobactam plus amikacin plus vancomycin, as empirical postoperative antibiotics would both effectively treat 78% of chronic osteomyelitis cases overall. The most effective practical oral combinations were co-amoxiclav plus ciprofloxacin (61%) and co-trimoxazole plus ciprofloxacin (61%). Conclusions. This study reports antibiogram profiles in the developing-world setting that could potentially guide empirical antibiotic choices in the management of chronic osteomyelitis.