Emergence of group B type 15 strains as a cause of meningococcal infection in England and Wales

Abstract

Group B meningococci cause about 70~o of the clinical meningococcal infections that occur in England and Wales. Since 1974 we have monitored the serotypes of group B strains causing disease. During the mid-1970's, 60~ of group B strains isolated from clinical cases were serotype 2 (Jones & Tobin 1976) but in 1979 type 15 strains occurred as commonly as type 2a strains (17~o and 15~ respectively) (Jones & Eldridge 1981). In 1980 type 2a strains were completely replaced by type 2b strains (24~o) and no more than 3 or 4 group B type 2a strains have been encountered each year since then. The serotype 15 strains have continued to cause an increasing proportion of the group B infections and accounted for more than a third of these in 1983-84 (Table 1). During 1983, 1984 and 1985, strains of group B, serotype 15 meningococci, resistant to sulphonamides, have been associated with community-wide outbreaks in Plymouth, Stroud, and North-West England and the cases have been notable for occuring mainly amongst teenagers and young adults. These outbreaks have coincided with the general seasonal pattern of infection in England and Wales, being mainly in the first quarter of the year, but they have not been restricted to one season