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Carriage meningococcal isolates with capsule null locus dominate among high school students in a non-endemic period, Italy, 2012–2013
International Journal of Medical Microbiology ( IF 4.1 ) Pub Date : 2019-03-06 , DOI: 10.1016/j.ijmm.2019.03.004
Arianna Neri , Cecilia Fazio , Luigina Ambrosio , Paola Vacca , Annamaria Barbui , Laura Daprai , Caterina Vocale , Iolanda Santino , Marco Conte , Lucia Rossi , Andrea Ciammaruconi , Anna Anselmo , Florigio Lista , Paola Stefanelli

Meningococcal disease incidence in Italy remains quite low in the overall population except for infants. Within a study on carriage isolates among high school students we aimed to define: i) the prevalence of carriage isolates, ii) the phenotypic and iii) the molecular features of meningococci by Whole Genome Sequencing (WGS).

A total of 1697 pharyngeal samples from undergraduate students (age range 14–19 years) were collected from 2012 to 2013 from six larger cities in Italy. One hundred and twenty culture positive meningococci (7%) were analyzed. Carriage isolates were sent to the National Reference Laboratory for invasive meningococcal disease (IMD) for PCR-based serogroup identification, Multilocus Sequence Typing, PorA and FetA typing. Moreover, factor H binding protein (fHbp), Neisseria Heparin Binding Antigen (NHBA) and Neisserial adhesin A (NadA) were typed. Core genome MLST (cgMLST) was performed on a subsample of 75 carriage isolates.

Capsule null locus (cnl) predominated (47%), followed by serogroup B (27%). The antimicrobial susceptibility profile revealed an high prevalence of reduced susceptibility to penicillin G (54%) and a full susceptibility to ceftriaxone, ciprofloxacin and rifampicin. Carriage isolates presented a high genetic diversity: the clonal complexes (ccs) cc1136, cc198 and cc41/44, were the predominant. An high heterogeneity was also observed for PorA and FetA types. The fhbp and nhba genes were identified in all the carriage isolates; only 5% of the carriage isolates presented the nadA gene. The core genome MLST analysis revealed that the majority of the cnl isolates clustered in a distinct group.

The evidence gathered during this study provides the estimate of carriage isolates in high school students in a non-epidemic period in Italy that was lower than expected. Moreover, the highest proportion of carriage isolates were cnl and, overall, they were molecular heterogeneous.



中文翻译:

在非流行时期,意大利,2012-2013年,具有空位基因座的脑膜炎球菌分离株占主导地位

除婴儿外,意大利的脑膜炎球菌病发病率仍然很低。在一项针对高中生中分离携带物的研究中,我们的目标是:i)分离携带物的流行; ii)表型;以及iii)全基因组测序(WGS)的脑膜炎球菌的分子特征。

从2012年至2013年,从意大利六个较大的城市中收集了总共1697份本科生(14至19岁年龄段)的咽样本。分析了120个培养阳性脑膜炎球菌(7%)。将分离株送至国家参考实验室进行侵袭性脑膜炎球菌疾病(IMD),以进行基于PCR的血清群鉴定,多基因座序列分型,PorA和FetA分型。此外,输入了H因子结合蛋白(fHbp),奈瑟氏菌肝素结合抗原(NHBA)和奈瑟氏粘附素A(NadA)。核心基因组MLST(cgMLST)在75个运输分离株的子样本上进行。

胶囊无效基因座(cnl)占主导地位(47%),其次是血清群B(27%)。抗菌药物敏感性分布表明,对青霉素G的敏感性降低的比例很高(54%),对头孢曲松,环丙沙星和利福平的敏感性很高。支架分离株具有很高的遗传多样性:主要的克隆复合体(cc s)cc1136,cc198和cc41 / 44。PorA和FetA类型也观察到高度异质性。该的fHbpnhba基因在所有车厢分离鉴定; 仅5%的运输分离株呈现nadA基因。核心基因组MLST分析显示,大部分cnl 聚集在不同组中的分离株。

这项研究期间收集的证据提供了在意大利非流行时期高中生中携带的隔离病菌的估计值,低于预期的估计值。此外,运输分离株的最高比例是cnl,总体上讲,它们是分子异质的。

更新日期:2019-03-06
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