Challenges in Treating Mycobacterium chelonae/abscessus Prosthetic Joint Infection

Prosthetic joint infections (PJIs) remain a major complication of arthroplasty, most of which are caused by Staphylococcus aureus and gram-negative bacteria. Unfortunately, cultures are false negative in upward of 7 percent of patients with suspected PJIs, and commonly in infections caused by rare rapidly growing mycobacterium (RGM) species. Guidelines recommend 6 months of antimycobacterial therapy for bone diseases caused by RGM, with empiric therapy consists of an oral macrolide (clarithromycin or azithromycin) plus tobramycin and imipenem-cilastatin. Definitive treatment of PJI due to RGM should be guided by antimicrobial susceptibility, however, most microbiology laboratories are unable to differentiate between M. chelonae and M. abscessus. Furthermore, treatment of M. chelonae PJI is challenging due to multidrug resistance and the dearth of oral antibiotics for therapy. This case report investigates a patient with PJI caused by M. chelonae and M. abscessus. The initial treatment with imipenem-cilastatin was complicated by drug induced seizures, further limiting therapy options.