Observational study of nasopharyngeal carriage of Neisseria meningitidis in applicants to a military academy in the Russian Federation

Abstract Objective To determine the carriage and the serogroup distribution of Neisseria meningitidis in military academy applicants in the Russian Federation. Design This was a prospective, observational study of adults aged >18 years from a military academy; applicants who had samples taken on arrival (Day 1), and applicants who had samples taken after passing exams (Day 30) and 60 days after arrival. N. meningitidis serogrouping was determined by slide agglutination tests of isolates and real-time PCR. Results Samples were provided by 671 applicants on Day 1 and 261 applicants on Day 30, with 232 of these also providing samples on Day 60. N. meningitidis was detected in 16.2% of samples from Day 1, 7.7% of samples from Day 30 and 15.9% of samples from Day 60. Serogroup composition was most diverse at Day 1, with serogroups B and W dominant (40% [17/43 isolates] and 9% [4/43], respectively; 30% [13/43] ungroupable); by Day 60, there was a low diversity, with 58% (14/24 isolates) serogroup W. Conclusions While carriage of N. meningitidis in this study appeared stable, there was an increase in carriers of serogroup W in this population. Given recent increases in outbreaks attributed to serogroup W, further monitoring may be considered.