Clinic of Children's Diseases, Institute of Clinical Medicine, Faculty of Medicine, Vilnius University, Vilnius, Lithuania.
Pediatric Center, Vilnius University Hospital Santaros Klinikos, Vilnius, Lithuania.
BMC Microbiol. 2023 Nov 17;23(1):352. doi: 10.1186/s12866-023-03111-5.
Neisseria meningitidis can be carried asymptomatically in the human oropharynx without causing symptoms. Meningococcal carriage is relevant to the epidemiology of invasive meningococcal disease (IMD). No carriage studies have been performed among the general population in Lithuania, whereas the incidence of IMD in Lithuania was among the highest in European countries from 2009 to 2019.
We analyzed a total of 401 oropharyngeal samples collected from university students from December 2021 to February 2023 for N. meningitidis carriage using direct swab PCR assays and culture. The overall carriage prevalence based on both or either swab PCR or culture was 4.99%. PCR-based assays were used to characterize 15 carriage isolates, including detection of genogroup, multilocus sequence typing profile, and typing of antigens PorA and FetA. The most common carriage isolates were capsule null locus (cnl), accounting for 46.7%, followed by genogroups B (26.7%) and Y (13.3%). We also performed a molecular characterization of invasive N. meningitidis isolates collected during the COVID-19 pandemic and post-pandemic period to understand better the meningococcal carriage in the context of prevailing invasive strains. Despite the substantial decrease in the incidence of IMD during the 2020-2022 period, clonal complex 32 (CC32) of serogroup B continued to be the most prevalent IMD-causing CC in Lithuania. However, CC32 was not detected among carriage isolates. The most common CCs were CC269, CC198, and CC1136. The antigen peptide variants found in most carried isolates were classified as 'insufficient data' according to the MenDeVAR Index to evaluate the potential coverage by the 4CMenB vaccine. Nearly half of the isolates were potentially covered by the Men-Fhbp vaccine. Resistance to ciprofloxacin was detected only for one cnl isolate. All isolates were susceptible to penicillin and ceftriaxone. Our analysis identified frequent partying (≥ 4 times/month) as a risk factor for meningococcal carriage, whereas smoking, living in a dormitory, and previous COVID-19 illness were not associated with the carriage.
Our study revealed a low prevalence of meningococcal carriage among university students in Lithuania. The carriage isolates showed genetic diversity, although almost half of them were identified as having a null capsule locus.
脑膜炎奈瑟菌可无症状地在人体口咽部携带而不引起症状。脑膜炎奈瑟菌带菌状态与侵袭性脑膜炎奈瑟菌病（ IMD ）的流行病学有关。在立陶宛，尚未对普通人群进行带菌研究，而 2009 年至 2019 年期间，立陶宛 IMD 的发病率在欧洲国家中最高。
我们使用直接拭子 PCR 检测和培养法，对 2021 年 12 月至 2023 年 2 月期间收集的 401 份来自大学生的咽拭子样本进行了脑膜炎奈瑟菌带菌情况的分析。基于两种或任何一种拭子 PCR 或培养的总体带菌率为 4.99%。我们使用 PCR 检测方法对 15 个带菌分离株进行了特征描述，包括检测基因群、多位点序列分型谱以及 PorA 和 FetA 抗原的分型。最常见的带菌分离株是荚膜缺失基因座（cnl），占 46.7%，其次是基因群 B（26.7%）和 Y（13.3%）。我们还对 COVID-19 大流行期间和大流行后期收集的侵袭性脑膜炎奈瑟菌分离株进行了分子特征分析，以更好地了解流行侵袭株背景下的脑膜炎奈瑟菌带菌情况。尽管在 2020-2022 年期间 IMD 的发病率显著下降，但 B 群血清型 32 克隆复合体（CC32）仍然是立陶宛最常见的引起 IMD 的 CC。然而，CC32 未在带菌分离株中检测到。最常见的 CC 是 CC269、CC198 和 CC1136。在大多数带菌分离株中发现的抗原肽变体根据 MenDeVAR 指数被归类为“数据不足”，以评估 4CMenB 疫苗的潜在覆盖范围。近一半的分离株可能被 Men-Fhbp 疫苗覆盖。仅一个 cnl 分离株对环丙沙星耐药。所有分离株对青霉素和头孢曲松敏感。我们的分析确定了频繁聚会（≥4 次/月）是脑膜炎奈瑟菌带菌的危险因素，而吸烟、居住在宿舍和以前感染过 COVID-19 与带菌无关。
我们的研究显示，立陶宛大学生中脑膜炎奈瑟菌带菌率较低。带菌分离株显示出遗传多样性，尽管其中近一半被鉴定为具有空荚膜基因座。
