Abstract
RATIONALE: The misuse of antibiotics and immunosuppressive agents has led to an increase in the incidence of infections caused by opportunistic pathogens, and even rare microbial infections such as Mycobacterium chelonae (MC) have emerged. Currently, there are very few reported cases of MC infection globally, and clinical experience in treating this disease is limited. This case report focuses on the treatment methods for infections caused by this bacterium, aiming to accumulate experience for clinicians in the diagnosis and treatment of this condition. PATIENT CONCERNS: This study reports a case of MC infection that occurred following an invasive cosmetic injection treatment. Due to the progression of the condition, medical intervention was required. The patient underwent combined medication and surgical therapy, and the treatment outcomes were subsequently tracked. DIAGNOSES: Histopathological examination of the skin lesion, fungal culture, and metagenomic detection of the infectious pathogen suggested MC infection. INTERVENTIONS: The patient underwent excision of the skin lesion, along with intravenous infusion of levofloxacin hydrochloride and sodium chloride injection at a dose of 0.4 g once daily and oral administration of rifampicin capsules at a dose of 0.45 g once daily. Complete lesion resolution was achieved at 1 month postoperatively. OUTCOMES: At the 1-month postoperative follow-up, the patient's rash had healed completely. LESSONS: This case fills a gap in domestic and international reports of MC infection following cosmetic filler injections. By employing metagenomic next-generation sequencing, the pathogen was rapidly identified within a short timeframe, significantly reducing the diagnostic delay associated with conventional bacterial culture and identification methods. Early radical lesion excision combined with a dual-antibiotic regimen (levofloxacin-rifampin) achieved complete resolution within 1 month, establishing a replicable treatment paradigm for cutaneous MC infections. Further multicenter prospective studies are warranted to optimize surgical margins and antimicrobial treatment duration.