Clarithromycin-based therapy with adjunctive photobiomodulation and microwave treatment for cutaneous Mycobacterium marinum infection

• Cutaneous Mycobacterium marinum infection often requires prolonged antibiotic therapy. • We report a retrospective case series using adjunctive photobiomodulation and microwave therapy. • The combined physical approach was associated with early local inflammatory control. • No treatment-related adverse events were observed in this cohort. • Adjunctive photobiomodulation-based therapy may be feasible in routine clinical practice. Cutaneous Mycobacterium marinum ( M. marinum ) infection poses substantial diagnostic and therapeutic challenges and often necessitates prolonged multidrug antibiotic regimens, which are frequently associated with poor adherence and potential toxicity . This study aimed to evaluate the feasibility, efficacy, and safety of a treatment strategy combining oral clarithromycin with red-light photobiomodulation (PBM) and microwave therapy. A single-center retrospective study was conducted on patients with M. marinum infection confirmed by culture and/or nested polymerase chain reaction (nested PCR) between 2021 and 2024. Clinical data were collected, and treatment outcomes were analyzed for patients who received combination therapy with oral clarithromycin, PBM and microwave treatment. All 14 patients were microbiologically confirmed to have M. marinum infection by culture and/or nested polymerase chain reaction (PCR)–based species identification. The median treatment duration was 4.5 weeks. Clinical cure was achieved in 10 patients, while 2 patients showed marked improvement and 2 exhibited partial improvement. No clinical recurrence was observed during a follow-up period of up to 36 months. A clarithromycin-based regimen supplemented with PBM and microwave therapy appears to be safe and potentially effective for cutaneous M. marinum infection and may facilitate early clinical improvement with favorable tolerability. During follow-up, no clinical relapse was documented.