Infection after knee arthroplasty in an immunosuppressive patient caused by Mycobacterium senegalense: a case report and literature review

Abstract Background The infection caused by nontuberculous Mycobacterium (NTM) is gradually increasing in both hospital-acquired infection and community-acquired infection. The most common NTM mainly includes Mycobacterium fortuitum group, the M. chelonae/abscessus group and the M. smegmatis group. The infection caused by the third biological variety in M. fortuitum group is rarely reported worldwide.Case presentation A 33-year-old female patient with 8-year history of rheumatoid arthritis underwent a right knee arthroplasty and developed postoperative infection. In hospital A, debridement was carried out to preserve the prosthesis joint. M. fortunatum was cultured in biopsy tissue taken out during operation and puncture fluid. Unfortunately, it is impossible to carry out the drug sensitivity test of Mycobacterium in hospital A. Local doctors used amikacin and levofloxacin to treat the patient empirically. In order to treat the infection accurately, the patient went to hospital B (a specialized hospital of tuberculosis) for drug sensitivity test. According to the results of drug sensitivity, cefoxitin, clarithromycin, amikacin and moxifloxacin were used in combination treatment. After two weeks of treatment, there was no significant remission, so the patient went to hospital C (a large teaching hospital) for joint prosthesis removal and bone cement frame transfer operation, and anti-infection treatment was carried out according to the drug sensitivity test results. One month later, the patient's condition improved significantly and the wound healed.Conclusions NTM should be considered as main pathogens in immunosuppressive patients when the wound did not heal due to infection. Simple antibiotic treatment is not good for deep abscess, but treatment combined with surgical debridement and appropriate antibiotics is obviously effective.