Background: Necrotizing fasciitis (NF) is a life-threatening soft tissue infection. It is usually caused by
Streptococcus pyogenes and other Gram-positive bacteria. Several reports, however, emphasize the
importance of Gram-negative rods in this infection.
Methods: We retrospectively studied all cases of monomicrobial necrotizing fasciitis hospitalized in our
center during the years 2002–2012. We compared clinical characteristics and outcomes of patients with
Gram-negative versus Gram-positive infection.
Results: Forty-five cases were reviewed, 19 caused by Gram-negative organisms, 10 of them Escherichia
coli, and 26 caused by Gram-positive organisms, 10 of them S. pyogenes. Compared to Gram-positive
infections , patients with Gram-negative infections were more likely to have a baseline malignancy (9/19,
47.4%) or to have undergone recent surgery (4/19, 42.3%)The 30-day mortality was higher among Gram-negative infected patients (8/19, 42.1% vs. 8/26, 30.8%). Creatine phosphokinase (CPK) was elevated in a
minority of patients with Gram-negative necrotizing fasciitis, and its absolute value was lower than in
Gram-positive necrotizing fasciitis.