Opat as a Treatment Regimen for Non-Tuberculous Mycobacteria (Ntm): A Case Series

NTM are emerging pathogens, especially in infections related to cosmetic procedures. Treatment of these infections can be complex, requiring combined antibiotic regimens, oral and intravenous, for prolonged periods, and antimicrobial resistance often poses a challenge. Outpatient Parenteral Antimicrobial Therapy (OPAT) has proven to be an effective approach, allowing patients to receive intravenous treatment outside the hospital environment. The authors describe a retrospective case series of patients diagnosed with healthcare-associated infections (HAIs) due to extrapulmonary NTM treated between January 2022 and May 2025. This study included 7 patients, 86% female (median age 43 years). The main source of infection was invasive cosmetic procedures, such as breast implants, gluteal fat grafting, facial hyaluronic acid fillers, and collagen infiltration. In only one patient did it occur after intra-articular ozone and corticosteroid infiltration in the knee. The mean time to symptom onset was 4 weeks, and to microbiological diagnosis with susceptibility testing was 4 months (2–18 months). Clinical presentation in all cases consisted of subcutaneous nodules and/or abscesses. Most cases (5 patients) had positive cultures for the Mycobacterium abscessus complex (M. abscessus subsp. abscessus, M. abscessus subsp. massiliense), and two for Mycobacterium wolinsky. Resistance of isolates to oral antimicrobials was 73%, with clarithromycin and sulfamethoxazole/trimethoprim showing the highest resistance rates (83%). Intravenous antibiotics were susceptible in 60% of isolates, with amikacin and tigecycline susceptible in all cultures; however, other IV antibiotics such as linezolid, imipenem, and cefoxitin were susceptible in only 33% of isolates. The IV antibiotics used were: amikacin (100%) with mean duration of 3 months; linezolid (71%) mean 5 months; tigecycline (57%) mean 3 months; and moxifloxacin (14%) mean 9 months; with a total median of 5.5 months (3–10 months). Due to high resistance to oral antimicrobials (73%), intravenous antibiotics were a frequent alternative in the treatment regimen in all cases. The OPAT regimen proved effective in most cases, allowing patients with NTM infection to be treated adequately outside the hospital environment.