[Genetic characteristics of Neisseria meningitidis strains obtained from healthy carriers during meningococcal infection outbreaks].

AIM: Genetic and antigenic characterization of Neisseria meningitidis strains isolated during meningococcal infection outbreaks from individuals in contact with patients with generalized form of meningococcal infection.

MATERIALS AND

METHODS

Strains obtained in 2007 - 2009 in Moscow during examination of individuals that were in contact with patients during meningococcal infection outbreaks were analyzed. Multilocus sequence typing, genetic subtyping and typing of VR fragment (FetA) techniques were used.

RESULTS

Data regarding investigated strains were submitted to the database at http://pubmlst.org/neisseria/. Previously undescribed sequence types were found in 12 strains, sequence-type could not be determined in 2 strains, 2 strains lacked VR fragment (FetA). Serogroup A meningococci had "P1.5-2,10: F3-5" antigenic profile and belonged to ST-75 and ST-3349 sequence-type, these data does not support the emergence of epidemically significant strains in the territory under surveillance. All typed serogroup C strains and 1 serogroup B strain are of "ST-41/44 complex/Lineage 3" clonal complex. Subtypes of serogroup C meningococci strains match subtypes of strains that cause generalized forms of infection, while serogroup B strains isolated from the carriers and strains isolated from the patients had different antigenic profiles. Ungrouppable strains had notably higher level of genetic and antigenic diversity: only 6 of 16 strains (37.5%) could be sequence-typed using earlier data, all these strains are of clonal complex "ST-53 complex" that consists mostly of strains isolated from the carriers. CONCLUSION. Ratio of meningococci population circulating in Moscow and subpopulation capable of causing generalized form of meningococcal infection (GFMI) is different for meningococci of various serogroups. Ungrouppable strains isolated from the carriers are highly different from strains causing GFMI.