Treatment of Mycobacterium fortuitum Infection of Total Knee Arthroplasty: A Case Report

Abstract

a b s t r a c tMycobacterium fortuitum is a rapidly growing bacterium that can cause infection at different sites in humans. Prosthetic infection caused by this bacterium has historically been a challenge, with reimplantation being unsuccessful in all but one case. M. fortuitum is resistant to almost all conventional antituberculous medications. There is no standardised treatment due to its rarity of occurrence. Here, we report a case of successful reimplantation with initial debridement surgery and 6 weeks of antibiotics. IntroductionMycobacterium fortuitum is a recognised cause of soft tissue infections at different sites in humans, for example, the cervical region, 1 abdominal wall, 2 skin 3 and breast. 4 In the literature, only a few cases of M. fortuitum prosthetic infections have been reported. The outcome was poor with inevitable failure of reimplantation except in one case. 5 There is no consensus of treatment. Case reportA 64-year-old woman had osteoarthritis of both knees. Preoperative X-rays of her left knee (Figure 1) showed no obvious sign of infection. There had been a history of intra-articular injection of unknown drugs of both knees before left total knee arthroplasty ( Figure 2) (Legacy posterior stabilized knee, Warsaw, Zimmer) was performed in 2003. Preoperative and intraoperative assessments showed no signs of infection. At 10 weeks after the operation, the patient complained of increased pain in her left knee. Physical examination showed increased temperature in the left knee with effusion. The blood test showed an elevated C-reactive protein level of 48.9 mg/L. Left knee aspiration was done and joint fluid was sent for investigation. Joint fluid culture was negative but microscopy found an increased number of neutrophils. Acid-fast bacillus smear was negative. Acid-fast bacillus culture yielded M. fortuitum, which was sensitive to amikacin, ciprofloxacin and imipenem but resistant to rifampicin, tetracycline and clarithromycin.Exploration was done 12 weeks after the first operation. Intraoperatively, pus was found inside the joint. Removal of the implant and insertion of a hand-moulded articulating cement spacer made from one pack of antibiotic-loaded cement (500 mg tobramycin in 40 g Simplex cement) were performed (Figure 3). Intraoperative frozen section showed >20 neutrophils per high-power field (40Â). Intraoperative fluid culture showed mycobacterial species. After the operation, the patient was placed on intravenous amikacin (500 mg/day) for 6 weeks and oral ciprofloxacin (500 mg twice daily orally) for 6 weeks in total, as suggested by the microbiologist. Two months after insertion of the cement spacer, the pain improved and signs of inflammation subsided. The extension to flexion range of her left knee was 10e80 . The C-reactive protein level went down from 48.9 mg/L to 5.0 mg/L. One month later, revision total knee replacement (Figure 4) was done. Intraoperative frozen section confirmed that the neutrophils count was <5 per

Nail Salon a Potential Source of a Rare Mycobacterium Fortuitum Infection In Proximal Tibia Megaprosthesis? A Case Report

“…However, there have also been cases reported of a M. Fortuitum infection in immunocompetent hosts. Other authors have previously presented prosthetic joint infections (PJI) in primary joint arthroplasty patients by NTM, including M. fortuitum [1,2,3,4,5]. In many of the cases reported in the literature on M. Fortuitum infections, the standard of treatment was surgical removal of the entire prosthesis, placement of an antibiotic spacer with concomitant intravenous antibiotics, and then replantation after the infection had cleared [1,2,3,4].…”

“…Other authors have previously presented prosthetic joint infections (PJI) in primary joint arthroplasty patients by NTM, including M. fortuitum [1,2,3,4,5]. In many of the cases reported in the literature on M. Fortuitum infections, the standard of treatment was surgical removal of the entire prosthesis, placement of an antibiotic spacer with concomitant intravenous antibiotics, and then replantation after the infection had cleared [1,2,3,4]. However, Eid et al presented eight patients with nine infections due to rapidly-growing Mycobacteria (seven knees, one hip, one elbow), three of which were M. fortuitum [5].…”