| Abstract [eng] |
The bacteria Neisseria meningitidis is responsible for the worldwide cases of life-threatening invasive meningococcal disease (IMD), the most commonly associated with clinical manifestations such as sepsis or meningitis. The incidence of IMD in Lithuania was among the highest in Europe from 2009 to 2019. IMD is associated with six meningococcal serogroups. Meningococci is often carried asymptomatically by humans in their oropharyngeal mucosa. N. meningitidis carriage is associated with age and social behavior such as frequent attendance at clubs/bars, smoking, living in close communities (military barracks, student dormitories). In industrialized countries, the highest carriage rate of N. meningitidis was found among 16-25-year-olds. A high frequency of carriage is associated with a greater transmission of N. meningitidis. In order to observe the novel emergence of serogroups and potentially pathogenic strains, it is important to carry out studies on meningococcal carriage among the general population. No studies on N. meningitidis carriage have been conducted in Lithuania among the general population. In this study, invasive strains of N. meningitidis collected in 2020-2022 were characterized by molecular methods, to better understand the meningococcal carriage in the context of prevailing invasive meningococcal strains in Lithuania. The prevalence of meningococcal carriage was detected among 18-25-year-old (n=401) university students living in Vilnius County and the carried N. meningitidis strains were genotyped. The real-time PCR method determined a 5% carriage prevalence of N. meningitidis. A small proportion of 18-19-year-olds were included in the study, which could potentially cause underestimated results of the incidence rate of carriage in the overall study population. Almost half of the carried N. meningitidis strains were without a capsule. Serogroup B strains were responsible for the majority of IMD cases in Lithuania from 2009 to 2022, and strains of this genogroup accounted for 26,7% of all carriage isolates. Y serogroup strains constituted about 1% of all invasive strains recovered in 2009-2019, but this serogroup was detected in 13,3% carriage isolates. This trend demonstrates that serogroup Y may increase IMD incidents in Lithuania. The serogroup B strains which belong to clonal complex 32 and accounted for most of meningococcal isolates recovered from 2009 to 2022 were not detected among carriage isolates. It is presumed that these strains are poor colonists and form a short-term relationship with the host. |
