Dynamic Changes in Microbial Composition During Necrotizing Soft-Tissue Infections in ICU Patients

Area of Science:

• Infectious Diseases
• Microbiology
• Surgical Infections

Background:

• Emerging multidrug-resistant (MDR) bacteria pose a significant threat in intensive care units (ICUs).
• Limited data exist on microbial population dynamics in necrotizing skin and soft tissue infections (NSTI), particularly during surgical interventions.

Purpose of the Study:

• To investigate the dynamic changes in microbial populations during repeated surgeries for severe NSTI in ICU patients.
• To identify the emergence of new pathogens and multidrug-resistant bacteria in NSTI patients undergoing reoperation.
• To assess the impact of microbial shifts on patient morbidity and mortality.

Main Methods:

• Retrospective study of 100 ICU patients with severe NSTI.
• Comparison of microbiological data from initial surgery and first reoperation samples.
• Analysis of clinical characteristics, NSTI features, and survival rates.
• Univariable and multivariable analyses to identify risk factors for microbial emergence.

Main Results:

• 54% of patients underwent reoperation; 27% of isolates at reoperation were MDR, a significant increase.
• Emergence of Gram-negative bacteria (e.g., Pseudomonas aeruginosa), staphylococci, and enterococci was observed.
• Broad-spectrum antibiotic therapy was associated with decreased microbial emergence.
• Initial adequate antibiotic therapy did not affect microbial emergence or survival.

Conclusions:

• Microbial emergence, including MDR bacteria, is frequent in NSTI patients undergoing repeated surgeries.
• Despite microbial shifts, the emergence of MDR bacteria did not significantly affect 1-year mortality.
• Broad-spectrum antibiotic use may play a role in mitigating microbial emergence in NSTI.