Characterization of Oropharyngeal Carriage Isolates ofNeisseria meningitidisin Healthy Korean Adolescents in 2015

Abstract

The meningococcus carriage rate is age-dependent, with a high prevalence in adolescents and young adults. This cross-sectional study aimed to estimate the oropharyngeal carriage rate of meningococcus among healthy Korean adolescents and its relationship with several population characteristics. The survey was conducted from April to May 2015 among 1,460 first-year high-school students in 9 high schools located in Gyeonggi province, Korea. Each student answered a short questionnaire assessing risk factors for carriage, and posterior pharyngeal wall swab samples were obtained. These samples were cultured on meningococcus-selective media, with colonies resembling meningococci identified using the Vitek® MS system (bioMérieux, Marcy l'Etoile, France). All isolates were characterized by molecular serogrouping and multilocus sequence typing (MLST). Meningococci were identified from 3.4% (49/1,460) swabs. Current smokers had significantly higher carriage rates than non-smokers (8.2% vs. 2.9%, P = 0.002), and boys had significantly higher carriage rates than girls (4.4% vs. 1.6%, P = 0.004). Serogroup B was the most common serogroup, followed by serogroup C, then 29E and Y. Twenty-seven different sequence types (STs) were identified; the most common were ST-3091, ST-11278, and ST-44. These belonged to clonal complexes (CCs) 269, 32, and 41/44, respectively, known as the hypervirulent clones. Evaluating meningococcal carriage is important to understand the epidemiology of meningococcal disease; however, little data exist in Korea. Similar to western countries, meningococcal serogroup B has emerged in Korea, and hypervirulent clones were identified. It is necessary to monitor the genetic and serologic characteristics of circulating meningococci and to assess the potential strain coverage of meningococcal vaccines.

Prevalence and serogroup changes of Neisseria meningitidis in South Korea, 2010–2016

“…The emergence of hypervirulent serogroup C (ST-11) led to the introduction of a meningococcal conjugate vaccine programme for serogroup C in Europe 29 , and the reduced proportion of serogroup C caused the proportion of serogroup B to increase 8 , 28 . It remains unclear if the emergence of one serogroup B infection belonging to B:P1.12-1, 1:F4-27:ST-44(cc41/44) in military trainees in 2015 resulted from the serogroup shifting due to vaccination, but serogroup B belonging to cc41/44 could be found in healthy South Korean adolescents in 2015 30 . Further surveillance and the introduction of a vaccine for serogroup B may be required when the prevalence of serogroup B in both patients and carriers is considered in South Korea.…”

“…Further surveillance and the introduction of a vaccine for serogroup B may be required when the prevalence of serogroup B in both patients and carriers is considered in South Korea. It is also possible that the emergence of serogroup E and serogroup non-typeable isolates may be associated with the partial application of a vaccine programme, even though serogroup E and non-groupable isolates tend to be common in asymptomatic carriage in healthy adolescents (E 12.2% and non-typeable 30.6) 30 . In our study, two IMD cases caused by serogroup E occurred in cancer patients who were immunocompromised.…”

“…Even though the vaccine programme for military trainees started in late 2012 31 , the quadrivalent meningococcal vaccine is still not included in the mandatory vaccine programme for the general population and is only part of the programme for military service and high-risk patients in South Korea. It is possible that the persistence and dissemination of serogroup C cc32 in years 2013 and 2016 were associated with the absence of a National Immunization Program except for the military service; therefore, an expansion of the programme may be needed in order to consider serogroup C as the second most commonly carried type in healthy adolescents in 2015 30 .…”

Meningococcal disease surveillance in the Asia–Pacific region (2020): The global meningococcal initiative

“…17 Carriage of serogroup B meningococci is also high in South Korea, with a carriage rate of 24.5% reported among 1460 first grade high school students (aged 16-17) in 2015. 18 Serogroup W circulation is significant across the Asia-Pacific region. Based on PCR testing, the Philippines reported that 16.7% ( n = 8/48) of blood and cerebrospinal fluid (CSF) specimens collected in 2018 were serogroup W. A higher percentage was reported in Australia during the first six months of 2019, with 25 out of 89 IMD cases (28%) being attributed to serogroup W (48% of these cases resulted in intensive care unit (ICU) admissions).…”

Prevalência e fatores associados ao estado de portador de Neisseria spp. em núcleos familiares: estudo de base populacional

“…A Coreia, por exemplo, apresenta baixa taxa de incidência de DMI (<2 casos/100.000 mil habitantes-ano) e baixa prevalência de portador de Nm (3,4%). A baixa prevalência de portadores pode ser atribuída a baixa incidência da DMI(KIM et al, 2017), ainda que essa relação não seja bem estabelecida.Além disso, a baixa prevalência de portadores pode ser explicada devido ao comportamento social dos adolescentes coreanos ser diferente dos adolescentes de outros países da Europa e das Américas.Não está claro na literatura o papel do contexto social em que os indivíduos vivem sobre a epidemiologia das NNP. Vimos que a epidemiologia dela é diferente da Nm quanto a distribuição etária, no entanto, residir em casa precária se mostra associado ao estado de portador de Nm e NNP.…”