Streptococcus pneumoniae Serotype 11D Has a Bispecific Glycosyltransferase and Expresses Two Different Capsular Polysaccharide Repeating Units

Oliver, Melissa B.; Jones, Chris; Larson, Thomas R.; Calix, Juan J.; Zartler, Edward R.; Yother, Janet; Nahm, Moon H.

doi:10.1074/jbc.m113.488528

Cited by 37 publications

(41 citation statements)

References 36 publications

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“…In contrast, wcjE sequences of the 11Av strains 3102-06, MZN265, and MNZ2293-C differ from the wcjE sequences of their 11A counterparts by only one nucleotide substitution. Similarly, sequences of the serotype 11D and 11A-1 cps loci differ by only a single nucleotide substitution (8) and, as discussed above, nucleotide polymorphisms resulting in notable antigenic changes are reported for serogroups 6 and 9 (6,25). In light of this evidence, genetic profiling of cps loci cannot unambiguously predict capsule identity, and the ability to serologically characterize pneumococcal strains remains crucial.…”

Section: Figmentioning

confidence: 95%

“…Successful recombination was verified by sequencing of the wcjE locus in all recombinant strains. The capsule-null variant AMB03 was created by recombinatorial replacement of the JC03 cps region spanning from wchA to wcrL with a Janus cassette containing the respective flanking regions, as described previously (8). Loss of capsule expression was verified by colony morphology and the Quellung reaction using factor serum 11c, which contains antibodies that bind to serotype 11A, 11C, 11D, and 11E capsule PSs (3).…”

Section: Pneumococcal Clinical Isolatesmentioning

confidence: 99%

“…Data were processed with NMRPipe software (11) and analyzed with NMRView software (12). Limited chemical shift assignments were made by comparison to recent NMR analyses of serogroup 11 capsule PS structures, which used similar PS purification and data acquisition methods (3,8).…”

Section: Pneumococcal Clinical Isolatesmentioning

confidence: 99%

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Spectrum of Pneumococcal Serotype 11A Variants Results from Incomplete Loss of Capsule O -Acetylation

Calix

Brady

et al. 2014

J Clin Microbiol

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Streptococcus pneumoniae is a significant bacterial pathogen that expresses >90 capsule serotypes. Conventional serotyping methods assume that each serotype is a genetically and antigenically distinct entity; however, recent investigations have revealed pneumococcal isolates that cannot be unambiguously serotyped because they share the properties of more than one serotype. Here, we employed a novel serotyping method and NMR spectroscopy to examine clinical isolates sharing properties of serotypes 11A and 11E. These ambiguous clinical isolates were provisionally named 11A variant (11Av) isolates. Serotype 11A pneumococci characteristically express capsule ␤-galactose-6-O-acetylation (␤Gal6OAc) mediated by the capsule synthesis gene wcjE, while 11E strains contain loss-of-function mutations in wcjE and completely lack the expression of ␤Gal6OAc. Although 11Av isolates also contained mutated wcjE alleles, 11Av clinical isolates were composed of antigenically homogeneous bacteria expressing reduced amounts of 11A-specific capsule antigen. NMR data confirmed reduced but detectable amounts of ␤Gal6OAc on 11Av capsule polysaccharide. Furthermore, the transformation of strains with wcjE alleles from 11Av strains was sufficient to restore partial ␤Gal6OAc in an 11E background. We conclude that, instead of being distinct entities, serotypes 11A and 11E represent two extremes of an antigenic spectrum resulting from variable capsule O-acetylation secondary to heterologous wcjE mutations. These findings challenge whether all clinically relevant pneumococci can be definitively categorized into distinct serotypes.

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Section: Figmentioning

confidence: 95%

Section: Pneumococcal Clinical Isolatesmentioning

confidence: 99%

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Spectrum of Pneumococcal Serotype 11A Variants Results from Incomplete Loss of Capsule O -Acetylation

Calix

Brady

et al. 2014

J Clin Microbiol

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“…Multiple studies have shown that different strains of the same serotype can have significant genetic differences in their cps loci. For instance, many serotype 11A strains isolated from the United States and Europe have large differences in their cps DNA sequences, resulting in misidentification of some 11A isolates as 11D in the past (19)(20)(21). Also, serotype 19A cps loci can be significantly different among different isolates (22).…”

Section: Discussionmentioning

confidence: 99%

Pneumococcus with the “6E” cps Locus Produces Serotype 6B Capsular Polysaccharide

et al. 2016

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Genetic studies of serogroup 6 isolates of Streptococcus pneumoniae identified putative serotype 6E. Although its capsular polysaccharide structure has not been elucidated, putative serotype 6E is described in an increasing number of studies as a potentially new serotype. We show here that SPEC6B, which is widely used as a target strain for serotype 6B opsonophagocytosis assays, has the genetic features of the putative serotype 6E but produces capsular polysaccharide identical to 6B capsular polysaccharide as determined by one-dimensional (1D) and 2D nuclear magnetic resonance (NMR). Thus, putative serotype 6E is a mere genetic variant of serotype 6B. Also, SPEC6B is appropriate as a target strain for serotype 6B opsonophagocytosis assays. This example illustrates the difficulties of assigning new bacterial serotypes based on genetic findings alone. Streptococcus pneumoniae is a Gram-positive bacterial species capable of producing more than 90 distinct capsule types (1). Due to the significance of S. pneumoniae as a human pathogen, the capsule diversity of pneumococci has been extensively studied serologically, biochemically, and genetically (1). In 2006, the genetic loci for capsule synthesis (cps loci) were sequenced for all known pneumococcal capsule types (2). Subsequent studies have found that genetic information in the cps locus correlates well with serologic and biochemical data for the capsular polysaccharide (PS). Thus, several well-described PCR protocols have been developed for serotyping purposes (e.g., see reference 3 and http://www.cdc.gov/streplab/downloads/pcr-oligonucleotide-primers.pdf; reviewed in reference 1), and it has become common to use genetic information to determine capsule serotypes.Genetic studies of serotype 6B cps have revealed two subgroups of cps loci that differ by Ͼ5% in the cps locus (4). The major subgroup was called class 1; the minor subgroup was called class 2 and has an ϳ300-bp indel element between wciN and wciO as its genetic hallmark. In addition, the class 2 locus contains a 9-nucleotide (nt) in-frame deletion in wze and four open reading frames upstream of wzg (5). Because of the stark genetic difference from class 1, it was suggested that class 2 may be a new serotype, "serotype 6E" (6). Although the authors of this study concluded that "serologic and biochemical characterization" is needed to confirm it as a new serotype (6), the putative serotype 6E is being increasingly treated as a distinct serotype in publications describing its discovery in all parts of the world (5, 7-10) and its association with antibiotic resistance (7, 10). Consequently, a recent study stated that there is an urgent need to determine the structure of capsular polysaccharide from the putative serotype 6E (10).Recently, several serotype 6B reference strains from the Pneumococcal Molecular Epidemiology Network collection were found to have "serotype 6E" genetic loci (10). Furthermore, SPEC6B, which is used as the serotype 6B reference target strain for the multiplexed opsonophagocytosis assa...

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“…Mild methanolysis is required for the detection of 3-deoxy-D-manno-oct-2-ulosonic acid (KDO), which is used by bacteria in the synthesis of lipopolysaccharides (65)(66)(67). GlcNAc also easily destroyed during hydrolysis therefore mild acid condition or methanolysis is needed (68)(69)(70)(71). On the contrary, liberation of all monosaccharides from polysaccharides is also not easily achieved, especially uronic acid-containing polysaccharides because glycosidic linkages between uronic acids and other monosaccharides are acid resistant during acid treatments.…”

Section: Acidic Hydrolysismentioning

confidence: 99%

Quality control of sweet medicines based on gas chromatography-mass spectrometry

Zhao

et al. 2015

DD&T

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Streptococcus pneumoniae Serotype 11D Has a Bispecific Glycosyltransferase and Expresses Two Different Capsular Polysaccharide Repeating Units

Cited by 37 publications

References 36 publications

Spectrum of Pneumococcal Serotype 11A Variants Results from Incomplete Loss of Capsule O -Acetylation

Spectrum of Pneumococcal Serotype 11A Variants Results from Incomplete Loss of Capsule O -Acetylation

Pneumococcus with the “6E” cps Locus Produces Serotype 6B Capsular Polysaccharide

Quality control of sweet medicines based on gas chromatography-mass spectrometry

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