Monomicrobial necrotizing fasciitis in a single center: the emergence of Gram-negative bacteria as a common pathogen

Area of Science:

• Infectious Diseases
• Microbiology
• Surgery

Background:

• Necrotizing fasciitis (NF) is a severe soft tissue infection, often attributed to Gram-positive bacteria like Streptococcus pyogenes.
• Emerging evidence highlights the significant role of Gram-negative rods in NF etiology.
• Understanding the distinct clinical features and outcomes associated with different bacterial causes of NF is crucial for effective management.

Purpose of the Study:

• To compare the clinical characteristics and outcomes of monomicrobial necrotizing fasciitis (NF) caused by Gram-negative versus Gram-positive organisms.
• To identify patient populations and clinical presentations associated with Gram-negative NF.
• To assess the mortality rates in Gram-negative versus Gram-positive NF.

Main Methods:

• Retrospective analysis of monomicrobial NF cases hospitalized between 2002 and 2012.
• Categorization of NF cases based on causative Gram-negative or Gram-positive organisms.
• Comparison of patient demographics, comorbidities, clinical presentation, laboratory values (including Creatine phosphokinase - CPK), and mortality between the two groups.

Main Results:

• Out of 45 NF cases, 19 were Gram-negative (10 Escherichia coli) and 26 were Gram-positive (10 Streptococcus pyogenes).
• Patients with Gram-negative NF were more likely to have underlying malignancy (47.4%) or recent surgery (42.3%).
• The 30-day mortality rate was higher in Gram-negative NF (42.1%) compared to Gram-positive NF (30.8%). CPK levels were less frequently elevated and lower in Gram-negative cases.

Conclusions:

• Gram-negative organisms, predominantly E. coli, accounted for 42% of monomicrobial NF cases in this study.
• Gram-negative NF cases were observed in immunocompromised or postoperative patients.
• These infections presented with typically normal CPK levels and were associated with significant mortality.