Application of multiple-locus variable number tandem repeat analysis to identify outbreak-associated Neisseria meningitides serogroup C sequence type 4821 in China.

Xiaoying Shan,Baofa Jiang,Ji Zhang,Haijian Zhou,Aiying Bai,Zhujun Shao,Li Xu,Guangchun Hu,Bingqing Zhu,I King Jordan

doi:10.1371/journal.pone.0116422

Abstract

Neisseria meningitidis (N. meningitidis) serogroup C sequence type (ST)-4821 caused an outbreak in 2010 in Shandong province of China. Twenty-one non-outbreak-associated strains were isolated, along with twenty-eight N. meningitides serogroup C ST-4821 isolates. Therefore, it’s essential to identify and clarify characterization of the real outbreak-associated strains with a rapid method during an outbreak investigation. In this study, multiple-locus variable number tandem repeat analysis (MLVA) was applied to analyze 84 N. meningitidis strains, among which 58 were recovered from two outbreaks and 26 were sporadic isolates. Three MLVA schemes with different combination of VNTR loci were tested, and two of them were suitable for isolates from China: scheme 2 with six loci was found to separate ST into finer resolution, and scheme 3 with five loci can be used to identify outbreak-associated isolates from the same outbreak that caused by N. meningitidis serogroup C ST-4821.

Highlights

Neisseria meningitidis (N. meningitidis), known as meningococcus, is a Gram-negative bacterium that is exclusively adapted to humans, and its natural habitat is the nasopharynx
All these N. meningitidis serogroup C isolates that caused outbreaks above belong to sequence type (ST) 4821 by multilocus sequence typing (MLST), which groups meningococci according to the allelic profile of seven housekeeping genes, assigning them into ST clonal complexes [6]
The majority of cases of invasive meningococcal disease were caused by N. meningitidis which belong to a limited number of clonal complexes known as the hypervirulent lineages [7]

Summary

Introduction

Neisseria meningitidis (N. meningitidis), known as meningococcus, is a Gram-negative bacterium that is exclusively adapted to humans, and its natural habitat is the nasopharynx This organism causes meningitis and other forms of meningococcal disease, such as meningococcemia, and remains a major worldwide health problem [1]. Molecular typing methods including pulsed-field gel electrophoresis (PFGE) and MLST have been developed and used for identifying outbreaks of meningococcal disease, both of them have weaknesses: PFGE is labor intensive and costly, and the interlaboratory comparison of data is challenging; while MLST is unfeasible in clinical laboratories as routine application because it is costly and takes several days for sequence typing [9, 10] Another molecular typing method, multiple-locus variable number tandem repeat analysis (MLVA), was taken in the present study to identify outbreak-associated isolates in two outbreaks caused by N. meningitidis serogroup C ST-4821 in China

Methods

Results

Conclusion