Epidemiological typing of Streptococcus pneumoniae from various sources inSweden and India using Box A PCR fingerprinting

Epidemiological typing of Streptococcus pneumoniae is essential to determin e strain relatedness and also to trace resistant clones. The novel Box A PC R assay was used for characterization of S. pneumoniae isolates from two Sc andinavian countries and to compare those from India on the Asian continent . In addition, the assay was employed to determine the clonality of 25 pneu mococcal strains from an outbreak in a day-care centre in Linkoping, Sweden . All 25 showed a unique pattern with 100% homology for 24 of them, thereby establishing the clonal nature of the outbreak. The pneumococcal strains i nvolved in the outbreak belonged to serotype 9 and were resistant to penici llin, with an MIC value of 2 mg/l. Thirty-eight genotypes were obtained whe n the Box A results were analysed by computer (Molecular Analyst(R) Softwar e with GelCompar). The discriminatory index of the method was D=0.98, which indicates excellent performance. No major segregation of strains from the different geographical locations was observed when a lower level of similar ity was used for typing (80%, 13 types). However, at the level chosen for g enotyping, 95% (38 genotypes) there was a clear geographical segregation. N o correlation between genotype and serotype was seen as strains from a comm on place of origin were most often of different serotypes. Computer-assiste d analysis of the results of Box A PCR typing facilitated the evaluation.