Necrotizing soft tissue infections
(NSTIs) are the most severe and rapidly progressing class of skin and soft
tissue infections (SSTIs). They are a surgical emergency and are associated
with high mortality and morbidity. While NSTIs remain relatively rare, their
incidence is steadily rising.
Earlier diagnosis and more focused antibiotic
treatments can potentially improve patient outcome, but both of these solutions
require a more accurate understanding of the microbial component of these
infections.
Streptococcus and Staphylococcus species,
especially S. aureus, are most commonly aerobic isolates and Clostridium spp. (C.perfringens and C. septicum) and Bacteroides fragilis group are the commonest
anaerobes detected. Clostridium spp. are often found in monomicrobial
infections and are associated with mortality rates greater than 50%. Certain
gram negative rods, including Escherichia coli and Pseudomonas species, are
also found,
While molecular detection methods, namely
16S sequencing, have not been traditionally used to identify the causative
microorganisms in NSTIs, they are becoming more commonplace as a diagnostic
tool for other types of SSTIs, especially for chronic wound infections. In
chronic wound infections, 16S sequencing has revealed a higher than previously
detected prevalence of obligate anaerobes. The use of 16S sequencing may lead
to the detection of a higher than expected proportion of obligate anaerobes in
NSTIs and consequently improve the care of patients with NSTIs.
