Microbiological profiles, antimicrobial resistance patterns and mortality-associated factors in necrotizing soft tissue infections: a 16-year retrospective cohort study
Xiaolin Ji, Zhenghui Wu, Kaikai Wang, Luting Jiang, Qianfeng Chen, Qihong Bei, Nanwei Lin, Fan Wu, Haohan Yu, Zhongqiu LuAbstract
Objectives
Necrotizing soft tissue infections (NSTIs) are rapidly progressive, life-threatening infections requiring prompt surgical and antimicrobial treatment. We aimed to characterize the microbiological profiles and antimicrobial resistance patterns of NSTIs and to assess their associations with 90-day mortality.
Methods
We retrospectively studied 212 adults with NSTIs admitted from December 2008 to May 2025. Clinical characteristics, laboratory parameters, pathogen groups and antimicrobial susceptibility patterns were compared between survivors and non-survivors. All 40 candidate factors were jointly included in ridge-penalized logistic regression, and estimation stability was assessed using bootstrap resampling.
Results
Overall 90-day mortality was 29.7% (63/212), and Gram-negative infections predominated (43.9%, 93/212). Mortality was 40.0% (12/30), 33.3% (31/93), and 66.7% (2/3) in Gram-positive, Gram-negative and fungal infections, respectively. Resistance analysis included 127 bacterial isolates from nine predominant taxa. Penicillin G resistance in Staphylococcus aureus and oxacillin resistance in coagulase-negative staphylococci were both 80.0%. Streptococcus pyogenes showed resistance to erythromycin and clindamycin in 75.0% and 62.5% of isolates, respectively. Among Escherichia coli isolates, ESBL positivity and resistance to levofloxacin and ciprofloxacin each occurred in 66.7%. Cefepime resistance was detected in 5.88% of Vibrio vulnificus isolates. In the jointly fitted ridge model, cardiovascular disease, hypertension, shock within 24h, coagulation measures, bilirubin, creatine kinase, potassium and lactate showed positive associations with mortality, whereas white blood cell count, albumin, CRP and PaCO2 showed inverse associations.
Conclusions
This long-term NSTI cohort showed Gram-negative predominance and species-specific heterogeneity in antimicrobial resistance. The ridge-penalized multivariable analysis characterized associations of microbiological categories and clinical indicators with 90-day mortality. These findings support locally tailored empirical therapy and the assessment of mortality risk.