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

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.

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Development of a Two-Step Multiplex PCR Assay for Typing of Capsular Polysaccharide Synthesis Gene Clusters of Streptococcus suis

Journal of Clinical Microbiology ◽

10.1128/jcm.03411-13 ◽

2014 ◽

Vol 52 (5) ◽

pp. 1714-1719 ◽

Cited By ~ 38

Author(s):

M. Okura ◽

C. Lachance ◽

M. Osaki ◽

T. Sekizaki ◽

F. Maruyama ◽

...

Keyword(s):

Multiplex Pcr ◽

Capsular Polysaccharide ◽

Streptococcus Suis ◽

Gene Clusters ◽

Pcr Assay ◽

Multiplex Pcr Assay ◽

Polysaccharide Synthesis

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Genetic Basis for the Structural Difference between Streptococcus pneumoniae Serotype 15B and 15C Capsular Polysaccharides

Infection and Immunity ◽

10.1128/iai.71.11.6192-6198.2003 ◽

2003 ◽

Vol 71 (11) ◽

pp. 6192-6198 ◽

Cited By ~ 71

Author(s):

Saskia van Selm ◽

Lisette M. van Cann ◽

Marc A. B. Kolkman ◽

Bernard A. M. van der Zeijst ◽

Jos P. M. van Putten

Keyword(s):

Streptococcus Pneumoniae ◽

Genetic Analysis ◽

Genetic Basis ◽

Capsular Polysaccharide ◽

Structural Difference ◽

Open Reading Frames ◽

Structural Level ◽

Reading Frame ◽

Polysaccharide Synthesis ◽

Short Tandem

ABSTRACT In a search for the genetic basis for the structural difference between the related Streptococcus pneumoniae capsular serotypes 15B and 15C and for the reported reversible switching between these serotypes, the corresponding capsular polysaccharide synthesis (cps) loci were investigated by keeping in mind that at the structural level, the capsules differ only in O acetylation. The cps locus of a serotype 15B strain was identified, partially PCR amplified with primers based on the related serotype 14 sequence, and sequenced. Sequence analysis revealed, among other open reading frames, an intact open reading frame (designated cps15bM) whose product, at the protein level, exhibited characteristics of previously identified acetyltransferases. Genetic analysis of the corresponding region in a serotype15C strain indicated that the same gene was present but had a premature stop in translation. Closer analysis indicated that the serotype 15B gene contained a short tandem TA repeat consisting of eight TA units. In serotype 15C, this gene contained nine TA units that resulted in a frameshift and a truncated product. Genetic analysis of 17 serotype 15B and 15C clinical isolates revealed a perfect correlation between the serotype and the length of the short tandem repeat in the putative O-acetyltransferase gene. The number of TA repeating units varied between seven and nine in the various isolates. Together, the data strongly suggest that the structural difference between serotypes 15B and 15C is based on variation in the short tandem TA repeat in the O-acetyltransferase gene and that the transition between serotypes is due to slipped-strand mispairing with deletion or insertion of TA units in the cps15bM gene.

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

International Journal of Food Microbiology ◽

10.1016/j.ijfoodmicro.2019.108332 ◽

2019 ◽

Vol 309 ◽

pp. 108332 ◽

Cited By ~ 1

Author(s):

Yu Pang ◽

Xi Guo ◽

Xiao Tian ◽

Fenxia Liu ◽

Lu Wang ◽

...

Keyword(s):

Vibrio Parahaemolyticus ◽

Capsular Polysaccharide ◽

Gene Clusters ◽

Molecular Serotyping ◽

Polysaccharide Synthesis

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Diversity of Capsular Polysaccharide Synthesis Gene Clusters in Streptococcus pneumoniae

The Journal of Biochemistry ◽

10.1093/oxfordjournals.jbchem.a022028 ◽

1998 ◽

Vol 123 (5) ◽

pp. 937-945 ◽

Cited By ~ 30

Author(s):

M. A.B. Kolkman ◽

B. A.M. van der Zeijst ◽

P. J.M. Nuijten

Keyword(s):

Streptococcus Pneumoniae ◽

Capsular Polysaccharide ◽

Gene Clusters ◽

Polysaccharide Synthesis

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

Microbiology ◽

10.1099/mic.0.025361-0 ◽

2009 ◽

Vol 155 (4) ◽

pp. 1039-1049 ◽

Cited By ~ 22

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.

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Polysaccharides and virulence of Burkholderia pseudomallei

Journal of Medical Microbiology ◽

10.1099/jmm.0.47043-0 ◽

2007 ◽

Vol 56 (8) ◽

pp. 1005-1010 ◽

Cited By ~ 35

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.

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