Invasive M-type 3 Streptococcus pyogenes affecting a family and a residential home.

This paper describes the first recognised United Kingdom outbreak of M-type 3 streptococci for 12 years. Four epidemiologically-linked invasive infections occurred in a residential home in northern England over two weeks. The index patient was admitted from home with necrotising fasciitis of the leg. Infection was subsequently detected in her husband (fatal pneumonia) another resident (fatal pneumonia) and a member of the care staff (parapharyngeal abscess). Screening of staff and residents in the home did not reveal any further infection or carriage. There is a substantial risk of serious secondary infection amongst the contacts of a patient with invasive Streptococcus pyogenes infection. Guidance is lacking, but needed, on the advisability of chemoprophylaxis in these circumstances.