Analyze genetic and phylogenetic interrelations between S. pneumoniae strains isolated from meningitis patients and carriers.
23 S. pneumoniae isolates (9 from bacterial meningitis patients, 9 from nasopharynx of bacterial carriers, 5 strains from museum collection of Gabrichevsky Moscow Research Institute of Epidemiology and Microbiology) were studied. S. pneumoniae ATCC 49619, S. mitis ATCC 49456 served as control strains. S. pneumoniae serotype determination was carried out in latex-agglutination reaction and quelling reaction. Multiplex PCR according to WHO protocols was used for molecular-genetic study and pneumolysin (ply), autolysin (lytA), surface cellular adhesin A (psaA) and capsule polysaccharide (cpsA) gene determination. Multilocus sequence-typing was carried out according to WHO scheme for 7 "housekeeping" segments--aroE, gdh, gki, recP, spi, xpt and ddl. Computer programs from available internet resources were used for data processing and dendrogram building. RESULTS; The S. pneumoniae isolates analyzed were established to belong to 19 sequence types that may be combined into 4 subclusters. Results of molecular-genetic and serologic typing were completely comparable.
Attribution of isolates from the same serotype and serogroup to different sequence-types gives evidence on the ongoing changes within serotype and as a result changes in allele profile of circulating S. pneumoniae isolates. Membership of isolates in separate subclusters gives evidence on close evolution relationship between isolates obtained from patients with bacterial meningitis and carriers. Certain isolates had not previously been registered in Russia and were probably imported from the territories of other countries.