The necrotizing gene

Necrotising fasciitis is usually caused by group A streptococcus and is classically an infection of the subdermal soft tissues, frequently complicated by toxic shock. In January 12 Lancet, Deepali Humar and colleagues from University of California, San Diego, show that β-haemolytic group G streptococcus can also produce necrotising fasciitis due to the presence of a functional homologue of a group A streptococcus gene encoding the β-haemolysin streptolysin S.

Humar et al. analyzed the DNA of β-haemolytic group G streptococcus isolated from three patients with severe necrotising soft tissue infections and found a homologue of the nine-gene group A streptococcus sag operon encoding the β-haemolysin streptolysin S (SLS). Studies on mice confirmed that SLS expression contributes to the pathogenesis of streptococcal necrotising soft tissue infection (Lancet 2002, 359:124–129).

"Strategies aimed at neutralization of SLS activity could be of therapeutic benefit as adjuncts to definitive surgical and...