Trueperella bernardiae is a Gram-positive bacterium that belongs to the normal flora but is rarely isolated as a pathogen, particularly a cause of postoperative infections following surgical procedures. This case report presents a surgical site infection caused by T. bernardiae that developed in a patient who underwent surgery for chronic otitis media and petrous apex cholesteatoma.

A 24-year-old male patient underwent a left total petrosectomy to treat chronic otitis media and petrous apex cholesteatoma. The patient had a 11-year history of intravenous drug use. A surgical site infection developed on the 15th postoperative day. Anaerobic culture of the aspirate revealed the growth of T. bernardiae, Staphylococcus epidermidis, Finegoldia magna, and Prevotella buccalis. Bacterial identification was performed using MALDI-TOF MS, and the antibiotic susceptibility was determined using the gradient test method. The patient was successfully treated with a combination of linezolid and piperacillin-tazobactam.

To our knowledge, this is the first reported case of a surgical site infection caused by T. bernardiae in Türkiye. T. bernardiae is an important pathogen that can cause polymicrobial infections, particularly in patients undergoing surgery, intravenous drug users, and individuals with chronic wounds. Accurate diagnosis requires advanced technological methods such as MALDI-TOF MS.