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Background: Neisseria meningitidis (N.meningitidis) bacteria belonging to clonal complex 4821 (CC4821) have been mainly reported in China and have been characterized by a high resistance rate to ciprofloxacin (CIP). The aim of this study was to assess the evolution of the DNA gyrase A (gyrA) gene from N.meningitidis CC4821 strains collected in China between 1978 and 2016. The complete sequence of gyrA gene from 77 strains are reported in this study and analyzed in the context of publicly available sequences from N. meningitidis of other CCs as well as other Neisseria species., Results: The phylogenetic analysis of CC4821 gyrA gene reveals at least 5 distinct genetic clusters. These clusters are not CC4821-specific showing that gyrA evolution is independent of CC4821 evolution. Some clusters contain sequences from other Neisseria species. Recombination within N.meningitidis strains and between Neisseria species was identified in SimPlot analysis. Finally, amino acid substitutions within GyrA protein were analyzed. Only one position, 91 (83 in E.coli gyrA gene), was linked to CIP resistance. Thirty-one additional putative resistance markers were identified, as amino acid substitutions were only found in resistant strains., Conclusions: The evolution of gyrA gene of CC4821 N.meningitidis strains is not dependent on CC4821 evolution or on CIP resistance phenotype. Only amino acid 91 is linked to CIP resistance phenotype. Finally, recombination inter- and intra-species is likely to result in the acquisition of various resistance markers, 31 of them being putatively mapped in the present study. Analyzing the evolution of gyrA gene within CC4821 strains is critical to monitor the CIP resistance phenotype and the acquisition of new resistance markers. Such studies are necessary for the control of the meningococcal disease and the development of new drugs targeting DNA gyrase.

Although serogroup W ST-11 complex (cc11) (W:cc11) Neisseria meningitidis has been widespread in China over the past ten years, its origin and genetic relatedness has not yet been described. In this study, we described the genetic relatedness and discuss the possible origin of Chinese W:cc11 isolates by comparing their genome sequences with those of other cc11 strains globally. Comparative genomic analysis with geo-temporally diverse cc11 isolates showed that the Chinese W:cc11 isolates exclusively formed two closely related subclusters within a distinct sublineage (proposed as the Chinese-strain sublineage) of lineage 11.1 close to the interface between the Hajj-strain sublineage and the South American-strain sublineage. Several isolates from Africa and Europe were closely related to the Chinese subclusters which were largely segregated from one another among distinct provinces of China. No alleles were identified that were unique to the Chinese isolates as a whole, though each subcluster possessed unique alleles differentiating itself from the other subcluster as well as closely related isolates within the extended sublineage. Three genes differentiated the two subclusters with allele combinations that were each present among the non-Chinese isolates within the wider sublineage. These results indicate that the Chinese W:cc11 isolates formed part of a previously undescribed W:cc11 sublineage that is closely related to, but distinct from, the Hajj-strain sublineage and South American-strain sublineage. The geographical source of the Chinese subclusters was indeterminate based on available data., (Copyright © 2019. Published by Elsevier Ltd.)

We aimed to investigate and understand the characterization and distribution of the autB gene in Neisseria meningitidis in China. autB is flanked by two conservative genes, smpB and glcD , and it can be present in the majority of meningococcal isolates, but not in 053442 of clonal complex 4821 (CC4821) which contains a 968 bp sequence. In this study, we sequenced the intervenient region between smpB and glcD in 178 Chinese N. meningitidis strains isolated from both patients and carriers. There were 110 serogroupable strains, other 68 were non-groupable (NG). Ninety nine of the 178 strains were clustered into 13 CCs, the remaining 79 were unassigned (UA). CC4821 is one of the dominant CCs in China. Forty of the 42 CC4821 strains and 26 of the 79 UA strains were autB -null, while the remaining 12 CCs were autB -positive. According to the N-terminal sequence, most (97/112) of the autB -positive strains were clustered into AutB1 and the remaining 15 were AutB2. The autB gene and its flanking intergenic sequences was superseded by a perfectly conservative sequence of an identical 968 bp in all of the autB -null N. meningitidis strains which had no identity with the relatively conservative intergenic sequences that flanked the autB gene in autB -positive strains. There was a 10 bp DNA uptake sequence (DUS) at the beginning of the interval 968 bp sequence in the autB -null strains while there was a 9 bp Haemophilus -specific uptake sequence (hUS) at the beginning of the partial holB gene and at the end of the partial tmk gene in autB -positive strains, holB and tmk gene were flanking the autB gene in Haemophilus . In conclusion, not all pathogenic N. meningitidis strains especially CC4821 possess the autB gene in China and the corresponding spacer region of the autB -null strains was not homologous to that found in autB -positive strains. There's a hypothesis that the DUS and hUS are likely to play a key part in the mechanism of uptake or loss of the autB gene.

Objective To study the prevalence of the fHbp genes in Neisseria meningitidis ( N. meningitidis ) isolates for further evaluation and development of serogroup B meningococcal vaccines in China. Methods A panel of 1012 N. meningitidis strains was selected from the national culture collection from 1956 to 2016, according to the years of isolation, locations, and strain sources. These were tested by FHbp variant typing. Multi-locus sequence typing (MLST) was performed on 822 of these samples, including 242 strains from clinical strains and 580 carrier-derived strains. Analysis based on sequence types, serogroups, and FHbp variations were used to summarize the prevalence and characteristics of N. meningitidis. Results There were 8 serogroups of N. meningitidis as well as a collection of nongroupable strains in this study. 1008 of 1012 N. meningitidis strains tested were positive for the fHbp gene. Serogroup A N. meningitidis (MenA) strains belonging to ST-1 and ST-5 clonal complexes harbored genes only encoding variant 1 (v1) FHbp. All MenW strains encoded v2 FHbp. 61.9% of clinical MenB strains were positive for v2 FHbp vs. 32.1% that were positive for v1. Among fHbp -positive carrier-derived MenB strains, v2 FHbp accounted for 90.8%. 79.7% of clinical MenC strains were positive for v1 FHbp and 20.3% were positive for v2 FHbp. Among carrier-derived MenC strains, v2 FHbp predominated. The number of major serogroups of N. meningitidis analyzed by MLST was 822, and the encoded FHbp showed CC- or ST-specific characteristics. Conclusion fHbp genes were detected in almost all N. meningitidis strains in this study. Therefore, it is possible that a vaccine against MenB or meningococci irrespective of serogroups, which includes FHbp, could be developed. Meningococcal vaccine development for China is a complex issue and these findings warrant further attention with respect to vaccine development. [ABSTRACT FROM AUTHOR]

Objective To systematically investigate the prevalence and genetic characteristics of 4CMenB and rLP2086 vaccine candidates among Neisseria meningitidis serogroup B (NmB) in China. Methods A total of 485 NmB strains isolated in 29 provinces of China between 1968 and 2016 were selected from the culture collection of the national reference laboratory according to the isolation year, location, and source. Multi-locus sequence typing (MLST) and porA gene sequencing were performed on all 485 study strains; PCR was used to detect the fHbp , nadA, and nhba gene of 432 strains; positive amplification products from the fHbp and nadA genes from all strains, as well as those of the nhba gene from 172 representative strains, were sequenced. Results MLST results showed that the predominant (putative) clonal complexes (CCs) of NmB isolates have changed over time in China. While strains that could not be assigned to existing (p)CCs were the biggest proportion, CC4821 was the most prevalent lineage (36.0%) since 2005. PCR and sequence analysis revealed that the 4CMenB and rLP2086 vaccine candidates were highly diverse. Respectively, 152 PorA genotypes and 83 VR2 sequences were identified with significant diversity within a single CC; the complete nadA gene was found in ten of 432 study strains; fHbp was present in most strains (422/432) with variant 2 predominating (82.9%) in both patient- and carrier- derived isolates; almost all strains harbored the nhba gene while sequences were diverse. Conclusions With regards to clonal lineages and vaccine candidate proteins, NmB isolates from China were generally diverse. Further studies should be performed to evaluate the cross-protection of present vaccines against Chinese NmB strains. [ABSTRACT FROM AUTHOR]