Title : Prevalence and characteristics of neisseria meningitidis carriage among high school students from the Vilnius region, Lithuania
Neisseria meningitidis causes invasive meningococcal disease (IMD), which is associated with significant mortality and long-term consequences, especially among young children. The incidence of IMD in Lithuania was among the highest in European countries during the past two decades reaching 2.9 cases/105 population in 2017. The worst disease-affected region was the Vilnius region, accounting for the majority of disease cases across all age groups. In 2020-2022, the incidence of IMD decreased in Lithuania accounting for approx. 0.36 cases/105 population. The drop is presumably related to COVID-19 restriction measures and vaccination against serogroup B meningococci. Oropharyngeal carriage of N. meningitidis is thought to be a prerequisite for the development of IMD. In industrialized countries, meningococcal carriage reaches a peak in young adults, however no data exist on N.meningitidis carriage among Lithuanians of 18-25-years-old. For the current study, oropharyngeal swabs were collected in 2022 from 300 students. N.meningitidis was detected and identified by culture and quantitative real-time PCR by targeting ctrA and porA genes. The genogroup and the MLST profile of isolates were determined by conventional PCR. Carriage prevalence was 4.33% (13/300). Most carriage isolates were genogroup B (30%) and capsule null (53.8%). Two isolates possessed the ctrA gene, however they were non-genogroupable in genotypic assays. The dominant genogroup B was compatible with that implicated in IMD in Lithuania, however the majority of clonal complexes (cc) of carriage isolates were not similar to invasive ones: the most common clonal complex was cnl cc198, cc269, and cnl cc1136. Noticeably, cnl cc198 was also dominant among Swedish, Dutch and Italian young adults. One isolate of ST-213 (cc213) has the same genotype as that causing IMD in Lithuania. Circulating isolates of genogroup B cc269 have invasive potential as cc269 is among the IMD-causing isolates in many countries.
Audience take away:
• Oropharyngeal carriage of N. meningitidis is thought to be a prerequisite for the development of invasive meningococcal disease (IMD)
• This study provides new data on the meningococcal carriage in Lithuania, a country with high IMD incidence • The epidemiology of carriage revealedN. meningitidis isolates having an invasive potential
• The understanding of meningococcal epidemiology in countries with high IMD incidence is crucial for the development of future public health and vaccination policy.
• The faculty could use the results of the current study to expand their research or teaching to address public health interventions.