Seasonal Variation of Group a Streptococcus (GAS) – Related Necrotising Fasciitis Cases in a UK Teaching Hospital

Necrotizing fasciitis is a diverse syndrome primarily involving the fascia but also occasionally the overlying skin and underlying muscles. Non-necrotising lower limb cellulitis has been reported to have a marked seasonal variation in our area. We are describing the seasonal variation of our necrotising fasciitis cases.

The medical records of all the patients that were admitted to our institution with a diagnosis of necrotizing fasciitis, from January 1994 to December 2003, were retrospectively reviewed.

The necrotising fasciitis infections peaked every year in the spring time, as previously described for cellulitis. The increased incidence was only apparent for group A streptococcus related necrotising fasciitis cases. The diagnosis carried 21% mortality during the same admission. Overall, 39% of the patients had a bad outcome, defined as either death during the same admission, limb amputation or severe disability. 73% of patients who experienced a bad outcome were found to have Group A streptococcus compared to only 41% of the patients in the good outcome group.

A seasonal variation was noted for Group A streptococcus associated necrotising fasciitis, that remains a lethal condition. As patients with Group A streptococcus associated necrotising fasciitis tend to have a worse outcome in our series, increased awareness and targeted antibiotic therapy may enhance clinical outcomes. Knowledge of microbiology might also inform infection control decisions.