Abdominal wall abscess due to Mycolicibacterium neworleansense: a case report

INTRODUCTION: Non-tuberculous mycobacteria (NTM) are widely distributed in the natural environment and can cause skin and soft tissue infections, typically through traumatic injuries or invasive medical procedures, especially in susceptible populations. Commonly encountered pathogens include Mycobacterium marinum and Mycobacterium abscessus, among others. However, cutaneous infections caused by Mycolicibacterium neworleansense are extremely rare. This report presents a case of abdominal wall abscess caused by Mycolicibacterium neworleansense, which was successfully managed with surgical debridement combined with targeted antimicrobial therapy. The aim of this report is to enhance clinical awareness of Mycolicibacterium neworleansense infections, optimize diagnostic and therapeutic strategies, and provide a reference for clinical practice. CASE PRESENTATION: A 74-year-old male with type 2 diabetes mellitus was admitted to the hospital with an abscess at the long-term insulin injection site on his left abdominal wall. After admission, surgical incision and drainage of the abscess were performed. Microbiological culture of the intraoperative pus specimen grew non-tuberculous mycobacteria, which were subsequently identified as Mycolicibacterium neworleansense using 16S rRNA gene sequencing combined with biochemical profiling. Antimicrobial susceptibility testing demonstrated resistance to macrolides and tetracyclines, but susceptibility to trimethoprim-sulfamethoxazole, aminoglycosides, moxifloxacin, and imipenem. Following surgical intervention, the patient received a combined antibiotic regimen of trimethoprim-sulfamethoxazole and moxifloxacin, leading to successful clinical resolution of the infection. CONCLUSION: Mycolicibacterium neworleansense can cause subcutaneous abscesses following injection-related invasive procedures. Successful management of such infections depends on precise pathogen identification via molecular and biochemical approaches, targeted antimicrobial therapy guided by susceptibility testing, and appropriate surgical intervention.