Carbapenem-resistant Acinetobacter baumannii causing osteomyelitis and infections of skin and soft tissues in hospitals of Medellin, Colombia

Introduction: Acinetobacter baumannii is an opportunistic bacterium which infects seriously ill patients, particularly those with ventilator-associated pneumonia and bacteremia. The emergence of resistance to carbapenem limits the options for the treatment of infections caused by this bacterium. Objective: To describe the clinical and molecular characteristics of infections caused by carbapenem-resistant A. baumannii in Medellin hospitals. Materials and methods: A cross-sectional descriptive study was carried out in five Medellin hospitals over a 2-year period. Clinical information was obtained from medical histories of patients. The presence of carbapenemases was evaluated by three-dimensional test and PCR. Molecular typing was performed using PFGE and MLST. Results: The study included 32 patients, 13 of whom presented skin and soft tissue infections (n=7, 21.9%) or osteomyelitis (n=6, 18.7%). Resistance rates of the isolates exceeded 80% for all the antibiotics evaluated except colistin and tigecycline. Carbapenemases OXA-23 and OXA-51, as well as the insertion sequence ISAba1, were detected in all the isolates. PFGE revealed high genetic diversity in the isolates and MLST showed clones ST229 and ST758 are circulating in the city. Conclusion: In contrast to previous reports, the results of the present study showed osteomyelitis and infections of skin and soft tissues to be the main infections caused by carbapenem-resistant A. baumannii in Medellin hospitals and revealed its importance as an etiological agent for this type of infections.