Developing a novel molecular serotyping system based on capsular polysaccharide synthesis gene clusters of Vibrio parahaemolyticus

2019 ◽  
Vol 309 ◽  
pp. 108332 ◽  
Author(s):  
Yu Pang ◽  
Xi Guo ◽  
Xiao Tian ◽  
Fenxia Liu ◽  
Lu Wang ◽  
...  
Keyword(s):  
Vibrio Parahaemolyticus ◽  
Capsular Polysaccharide ◽  
Gene Clusters ◽  
Molecular Serotyping ◽  
Polysaccharide Synthesis

scholarly journals Genetic diversity of capsular polysaccharide biosynthesis in Klebsiella pneumoniae clinical isolates

Microbiology ◽  
2009 ◽  
Vol 155 (12) ◽  
pp. 4170-4183 ◽  
Author(s):  
Hung-Yu Shu ◽  
Chang-Phone Fung ◽  
Yen-Ming Liu ◽  
Keh-Ming Wu ◽  
Ying-Tsong Chen ◽  
...  
Keyword(s):  
Klebsiella Pneumoniae ◽  
Capsular Polysaccharide ◽  
Sequence Data ◽  
Gene Clusters ◽  
Epidemiological Studies ◽  
Clinical Isolates ◽  
Polysaccharide Biosynthesis ◽  
Bacterial Surface ◽  
Polysaccharide Synthesis ◽  
Hospital Acquired

Klebsiella pneumoniae is an enteric pathogen causing community-acquired and hospital-acquired infections in humans. Epidemiological studies have revealed significant diversity in capsular polysaccharide (CPS) type and clinical manifestation of K. pneumoniae infection in different geographical areas of the world. We have sequenced the capsular polysaccharide synthesis (cps) region of seven clinical isolates and compared the sequences with the publicly available cps sequence data of five strains: NTUH-K2044 (K1 serotype), Chedid (K2 serotype), MGH78578 (K52 serotype), A1142 (K57 serotype) and A1517. Among all strains, six genes at the 5′ end of the cps clusters that encode proteins for CPS transportation and processing at the bacterial surface are highly similar to each other. The central region of the cps gene clusters, which encodes proteins for polymerization and assembly of the CPS subunits, is highly divergent. Based on the collected sequence, we found that either the wbaP gene or the wcaJ gene exists in a given K. pneumoniae strain, suggesting that there is a major difference in the CPS biosynthesis pathway and that the K. pneumoniae strains can be classified into at least two distinct groups. All isolates contain gnd, encoding gluconate-6-phosphate dehydrogenase, at the 3′ end of the cps gene clusters. The rmlBADC genes were found in CPS K9-positive, K14-positive and K52-positive strains, while manC and manB were found in K1, K2, K5, K14, K62 and two undefined strains. Our data indicate that, while overall genomic organization is similar between different pathogenic K. pneumoniae strains, the genetic variation of the sugar moiety and polysaccharide linkage generate the diversity in CPS molecules that could help evade host immune attack.

scholarly journals Genetic analysis of capsular polysaccharide synthesis gene clusters in 79 capsular types of Klebsiella spp

2015 ◽  
Vol 5 (1) ◽  
Author(s):  
Yi-Jiun Pan ◽  
Tzu-Lung Lin ◽  
Chun-Tang Chen ◽  
Yi-Yin Chen ◽  
Pei-Fang Hsieh ◽  
...  
Keyword(s):  
Genetic Analysis ◽  
Capsular Polysaccharide ◽  
Gene Clusters ◽  
Polysaccharide Synthesis ◽  
Klebsiella Spp

scholarly journals VPsero: Rapid Serotyping of Vibrio parahaemolyticus Using Serogroup-Specific Genes Based on Whole-Genome Sequencing Data

2021 ◽  
Vol 12 ◽  
Author(s):  
Shengzhe Bian ◽  
Yangyang Jia ◽  
Qiuyao Zhan ◽  
Nai-Kei Wong ◽  
Qinghua Hu ◽  
...  
Keyword(s):  
Vibrio Parahaemolyticus ◽  
High Throughput Sequencing ◽  
Capsular Polysaccharide ◽  
High Specificity ◽  
Gene Clusters ◽  
Whole Genome Sequencing Data ◽  
Sequencing Data ◽  
Sequencing Technologies ◽  
Marine Habitats ◽  
Specificity And Sensitivity

Vibrio parahaemolyticus has emerged as a significant enteropathogen in human and marine habitats worldwide, notably in regions where aquaculture products constitute a major nutritional source. It is a growing cause of diseases including gastroenteritis, wound infections, and septicemia. Serotyping assays use commercially available antisera to identify V. parahaemolyticus strains, but this approach is limited by high costs, complicated procedures, cross-immunoreactivity, and often subjective interpretation. By leveraging high-throughput sequencing technologies, we developed an in silico method based on comparison of gene clusters for lipopolysaccharide (LPSgc) and capsular polysaccharide (CPSgc) by firstly using the unique-gene strategy. The algorithm, VPsero, which exploits serogroup-specific genes as markers, covers 43 K and all 12 O serogroups in serotyping assays. VPsero is capable of predicting serotypes from assembled draft genomes, outputting LPSgc/CPSgc sequences, and recognizing possible novel serogroups or populations. Our tool displays high specificity and sensitivity in prediction toward V. parahaemolyticus strains, with an average sensitivity in serogroup prediction of 0.910 for O and 0.961 for K serogroups and a corresponding average specificity of 0.990 for O and 0.998 for K serogroups.

scholarly journals Genetic Structure, Function, and Evolution of Capsule Biosynthesis Loci in Vibrio parahaemolyticus

2021 ◽  
Vol 11 ◽  
Author(s):  
Shengzhe Bian ◽  
Wenhong Zeng ◽  
Qiwen Li ◽  
Yinghui Li ◽  
Nai-Kei Wong ◽  
...  
Keyword(s):  
Genetic Structure ◽  
Vibrio Parahaemolyticus ◽  
Large Scale ◽  
Capsular Polysaccharide ◽  
Evolutionary Relationship ◽  
Gene Clusters ◽  
Extracellular Polysaccharides ◽  
Gene Trees ◽  
Species Trees ◽  
Antigenic Properties

Capsule-forming extracellular polysaccharides are crucial for bacterial host colonization, invasion, immune evasion, and ultimately pathogenicity. Due to warming ocean waters and human encroachment of coastal ecosystems, Vibrio parahaemolyticus has emerged as a globally important foodborne enteropathogen implicated in acute gastroenteritis, wound infections, and septic shock. Conventionally, the antigenic properties of lipopolysaccharide (LPS, O antigen) and capsular polysaccharide (CPS, K antigen) have provided a basis for serotyping V. parahaemolyticus, whereas disclosure of genetic elements encoding 13 O-serogroups have allowed molecular serotyping methods to be developed. However, the genetic structure of CPS loci for 71 K-serogroups has remained unidentified, limiting progress in understanding its roles in V. parahaemolyticus pathophysiology. In this study, we identified and characterized the genetic structure and their evolutionary relationship of CPS loci of 40 K-serogroups through whole genome sequencing of 443 V. parahaemolyticus strains. We found a distinct pattern of CPS gene cluster across different K-serogroups and expanded its new 3′-border by identifying glpX as a key gene conserved across all K-serogroups. A total of 217 genes involved in CPS biosynthesis were annotated. Functional contents and genetic structure of the 40 K-serogroups were analyzed. Based on inferences from species trees and gene trees, we proposed an evolution model of the CPS gene clusters of 40 K-serogroups. Horizontal gene transfer by recombination from other Vibrio species, gene duplication is likely to play instrumental roles in the evolution of CPS in V. parahaemolyticus. This is the first time, to the best of our knowledge, that a large scale of CPS gene clusters of different K-serogroups in V. parahaemolyticus have been identified and characterized in evolutionary contexts. This work should help advance understanding on the variation of CPS in V. parahaemolyticus and provide a framework for developing diagnostically relevant serotyping methods.

scholarly journals Mutational analysis of genes implicated in LPS and capsular polysaccharide biosynthesis in the opportunistic pathogen Bacteroides fragilis

Microbiology ◽  
2009 ◽  
Vol 155 (4) ◽  
pp. 1039-1049 ◽  
Author(s):  
Sheila Patrick ◽  
Simon Houston ◽  
Zubin Thacker ◽  
Garry W. Blakely
Keyword(s):  
Capsular Polysaccharide ◽  
Mutational Analysis ◽  
Bacteroides Fragilis ◽  
Gene Clusters ◽  
Opportunistic Pathogen ◽  
Extracellular Polysaccharides ◽  
Phase Variable ◽  
Multiple Gene ◽  
Polysaccharide Biosynthesis ◽  
Group 1

The obligate anaerobe Bacteroides fragilis is a normal resident of the human gastrointestinal tract. The clinically derived B. fragilis strain NCTC 9343 produces an extensive array of extracellular polysaccharides (EPS), including antigenically distinct large, small and micro- capsules. The genome of NCTC 9343 encodes multiple gene clusters potentially involved in the biosynthesis of EPS, eight of which are implicated in production of the antigenically variable micro-capsule. We have developed a rapid and robust method for generating marked and markerless deletions, together with efficient electroporation using unmodified plasmid DNA to enable complementation of mutations. We show that deletion of a putative wzz homologue prevents production of high-molecular-mass polysaccharides (HMMPS), which form the micro-capsule. This observation suggests that micro-capsule HMMPS constitute the distal component of LPS in B. fragilis. The long chain length of this polysaccharide is strikingly different from classical enteric O-antigen, which consists of short-chain polysaccharides. We also demonstrate that deletion of a putative wbaP homologue prevents expression of the phase-variable large capsule and that expression can be restored by complementation. This suggests that synthesis of the large capsule is mechanistically equivalent to production of Escherichia coli group 1 and 4 capsules.

scholarly journals Polysaccharides and virulence of Burkholderia pseudomallei

2007 ◽  
Vol 56 (8) ◽  
pp. 1005-1010 ◽  
Author(s):  
M. Sarkar-Tyson ◽  
J. E. Thwaite ◽  
S. V. Harding ◽  
S. J. Smither ◽  
P. C. F. Oyston ◽  
...  
Keyword(s):  
Burkholderia Pseudomallei ◽  
Capsular Polysaccharide ◽  
Gene Clusters ◽  
Type I ◽  
Wild Type ◽  
Time To Death ◽  
Type Iii ◽  
Type Iv ◽  
Mutant Strains ◽  
Delayed Time

Burkholderia pseudomallei is the causative agent of melioidosis, an infectious disease of humans and animals. Gene clusters which encode capsular polysaccharide (type I O-PS) and LPS (type II O-PS), both of which play roles in virulence, have previously been identified. Here, the identification of two further putative clusters, type III O-PS and type IV O-PS, is reported. Mice challenged with type III O-PS or type IV O-PS mutants showed increased mean times to death (7.8 and 11.6 days) compared to those challenged with wild-type B. pseudomallei (3 days). To investigate the possible roles of polysaccharides in protection, mice were immunized with killed cells of wild-type B. pseudomallei or killed cells of B. pseudomallei with mutations in the O antigen, capsular polysaccharide, type III O-PS or type IV O-PS gene clusters. Immunization with all polysaccharide mutant strains resulted in delayed time to death compared to the naïve controls, following challenge with wild-type B. pseudomallei strain K96243. However, immunization with killed polysaccharide mutant strains conferred different degrees of protection, demonstrating the immunological importance of the polysaccharide clusters on the surface of B. pseudomallei.

Sign in / Sign up

Export Citation Format

Share Document