Genetic Diversity of Neisseria meningitidis Serogroup C ST-4821 in China Based on Multiple-Locus Variable Number Tandem Repeat Analysis

Abstract

Neisseria meningitidis sequence type (ST)-4821 was first reported in China in 2003, and a new hyper-virulent lineage has been designated as the ST-4821 complex. A large number of N. meningitidis ST-4821 strains have been identified in China since 2003; however, the microevolution characteristics of this complex are unclear. Different combinations of variable number of tandem repeats (VNTR) loci were used in multiple-locus VNTR analysis (MLVA) to analyze 118 N. meningitidis serogroup C ST-4821 strains isolated from seventeen provinces between 2003 and 2012. Additionally, MLVA with five VNTR loci was performed due to its high discriminatory power. One hundred and eighteen isolates were found to comprise 112 subtypes based on MLVA, and 16 outbreak-associated strains were clustered into one group. These data indicate a high level of diversity for N. meningitidis ST-4821 due to microevolution in the last decade. In addition, the results revealed high similarity between isolates from the same geographic origins, which is helpful when monitoring the spread of N. meningitidis serogroup C ST-4821 and will provide valuable information for the control and prevention of bacterial meningitis in China.

Burden of Neisseria meningitidis infections in China: a systematic review and meta–analysis

“…In response to these outbreaks, meningococcal group A and C polysaccharide vaccines were subsequently used for routine immunization. Nonetheless, serogroup C continues to be isolated every year throughout China with ST–4821 dominant [14]. …”

Multilocus variable-number tandem-repeat analysis of Neisseria meningitidis serogroup C in China

“…One research group [16] screened VNTR loci from the genomes of NM strains Z2491, MC58 and FAM18, but did not use any strains from China; we therefore tested these VNTR loci in N. meningitidis strains from China in order to determine a suitable scheme for such strains. Moreover, we have previously reported that MLVA further discriminated between isolates of N. meningitidis serogroup C ST4821 and identified 112 MLVA genotypes (GTs) in 118 isolates [17]. In the present study, we extended this work using MLST and MLVA, to characterize 215 serogroup C N. meningitidis isolates, including 182 of closely related ST4821 complex.…”

“…A total of 215 N. meningitidis serogroup C isolates, obtained from 22 provinces in China from 2003 to 2012, were used in this study; DNA from each of the isolates was prepared as published previously [17]. MLST was performed as per published protocols [18] and ST data for 135 of the 215 isolates was utilized from a recent study [7].…”

“…MLST was performed as per published protocols [18] and ST data for 135 of the 215 isolates was utilized from a recent study [7]. Sixteen VNTR loci and MLVA were as described previously [17].…”