scholarly journals Structure and serology of the native polysaccharide antigen of type Ia group B Streptococcus

1980 ◽  
Vol 77 (5) ◽  
pp. 2931-2935 ◽  
Author(s):  
H. J. Jennings ◽  
K.-G. Rosell ◽  
D. L. Kasper
1979 ◽  
Vol 149 (1) ◽  
pp. 58-66 ◽  
Author(s):  
J Y Tai ◽  
E C Gotschlich ◽  
R C Lancefield

Group B streptococcus type Ib (strain H36B) was subjected to digestion with extracellular muralytic enzymes prepared from Streptomyces albus. Type Ib-specific polysaccharide antigen was isolated from the lysate by alcohol precipitation and Sepharose 6B chromatography. The purified type Ib antigen has a Kd value of 0.31 on a Sepharose 4B column and contains four sugars, galactose, glucose, N-acetyl glucosamine, and sialic acid in a molar ratio of 2.05:0.86:1.00:0.90. Acid treatment (pH 2.0) of this polysaccharide results in partial degradation of the antigen (Kd = 0.41 on Sepharose 4B) with the loss of 93% of the sialic acid. The molar ratio of the remaining sugars in the polysaccharide remains identical to that in the native one. This suggests that the sialic acid is at the terminal position in the molecule. Both intact and acid-treated antigen cross-react with some type Ia and type Ic antisera as a result of the common Iabc determinant, but not with type II and type III antisera. Absorption studies indicate that Ib-specific determinant and Iabc determinant are on the same molecule and that sialic acid is not the cross-reactive determinant.


PEDIATRICS ◽  
1978 ◽  
Vol 62 (4) ◽  
pp. 620-621
Author(s):  
Gerald W. Fischer ◽  
James W. Bass ◽  
George H. Lowell ◽  
Martin H. Crumrine

The article by Bortolussi et al. on pneumococcal septicemia and meningitis in the neonat (Pediatrics 60:352, September 1977) was of great interest to us, since we have been analyzing the effect of antibody directed against Streptococcus pneumoniae on group B Streptococcus type III. We have recently shown (unpublished data) that antibody directed against S. pneumoniae type 14 precipitates the hot hydrochloric acid-extracted polysaccharide antigen of group B Streptococcus type III. Further studies have shown that this antibody is opsonic for group B Streptococcus type III in an in vitro bactericidal assay and protective in a suckling rat model of group B Streptococcus type III sepsis.1


1976 ◽  
Vol 143 (2) ◽  
pp. 258-270 ◽  
Author(s):  
C J Baker ◽  
D L Kasper ◽  
C E Davis

The type III polysaccharide of -roup B Streptococcus has been isolated and purified by a method that employs washing of intact cells at neutral pH. That the polysaccharide prepared by this procedure is the "native" type III antigen is suggested by its molecular size in excess of 10(6) daltons, its degradation by acid and heat treatment to a fragment with immunologic characteristics of the classical HCl antigen, and its type-specific serologic activity. The type III polysaccharide in native form contains sialic acid, galactose, glucose, glucosamine, heptose, and mannose. It is acidic in nature, is resistant to neuramindiase degradation, contains no O-acetyl groups, and does not share antigenic determinants with capsular type K1 antigen of Escherichia coli or Group B polysaccharide antigen of Neiserria meningitidis.


2015 ◽  
Vol 17 (5) ◽  
pp. 1102-1105 ◽  
Author(s):  
Prolay K. Mondal ◽  
Guochao Liao ◽  
Mohabul A. Mondal ◽  
Zhongwu Guo

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Erastus Lafimana Haimbodi ◽  
Munyaradzi Mukesi ◽  
Sylvester Rodgers Moyo

Abstract Background The main purpose of this study was to investigate the prevalence rate, antimicrobial susceptibility patterns and molecular characteristics of Streptococcus agalactiae isolated from pregnant women at 35 weeks of gestation and above, who attended antenatal screening at selected hospitals in Ohangwena and Oshikoto regions of Namibia. Results Out of 210 women screened for Group B Streptococcus (GBS), 12 (5.7%) were colonised of which 25.0% were colonised rectovaginally, 58.0% vaginally and 17.0% rectally. No significant association was reported between GBS colonisation and maternal age, geographic location, marital status, education, employment, parity, still births and miscarriages (P values > 0.05). Antimicrobial susceptibility was reported at 100% for ampicillin, penicillin & ceftriaxone which are commonly used for empiric treatment of infection with GBS. Resistance to tetracycline was reported at 100%. Tetracycline resistance gene tet(M) was present in 88.9% of the isolates only and none of the isolates presented with tet(O). Polysaccharide capsular type Ia was found in 9(50%) and Ib was found in 1(5.5%) of the total isolates. The remaining isolates were not typeable using PCR. Conclusion Streptococcus agalactiae’s positive rate was 5.7% among the pregnant women examined. Socio-demographic and obstetric factors had no influence on GBS colonisation (P values > 0.05). No resistance was reported to ampicillin, penicillin and ceftriaxone. No sensitivity was reported to tetracycline. Fifty percent of the isolates were capsular type Ia, 5.5% were type Ib and 44.4% were not typeable using PCR. The study provides crucial information for informing policy in screening of GBS in pregnant women.


1999 ◽  
Vol 181 (17) ◽  
pp. 5389-5394 ◽  
Author(s):  
Robin A. Ross ◽  
Lawrence C. Madoff ◽  
Lawrence C. Paoletti

ABSTRACT Group B Streptococcus (GBS) is the leading cause of bacterial sepsis and meningitis among neonates. While the capsular polysaccharide (CPS) is an important virulence factor of GBS, other cell surface components, such as C proteins, may also play a role in GBS disease. CPS production by GBS type III strain M781 was greater when cells were held at a fast (1.4-h mass-doubling time [td ]) than at a slow (11-htd ) rate of growth. To further investigate growth rate regulation of CPS production and to investigate production of other cell components, different serotypes and strains of GBS were grown in continuous culture in a semidefined and a complex medium. Samples were obtained after at least five generations at the selected growth rate. Cells and cell-free supernatants were processed immediately, and results from all assays were normalized for cell dry weight. All serotypes (Ia, Ib, and III) and strains (one or two strains per serotype) tested produced at least 3.6-fold more CPS at atd of 1.4 h than at atd of 11 h. Production of beta C protein by GBS type Ia strain A909 and type Ib strain H36B was also shown to increase at least 5.5-fold with increased growth rate (production at atd of 1.4 h versus 11 h). The production of alpha C protein by the same strains did not significantly change with increased growth rate. The effect of growth rate on other cell components was also investigated. Production of group B antigen did not change with growth rate, while alkaline phosphatase decreased with increased growth rate. Both CAMP factor and beta-hemolysin production increased fourfold with increased growth rate. Growth rate regulation is specific for select cell components in GBS, including beta C protein, alkaline phosphatase, beta-hemolysin, and CPS production.


1980 ◽  
Vol 58 (2) ◽  
pp. 112-120 ◽  
Author(s):  
Harold J. Jennings ◽  
Karl-Gunnar Rosell ◽  
Dennis L. Kasper

The native polysaccharide antigen isolated from type-III group B Streptococcus contains D-galactose (Gal), D-glucose (Glc), 2-acetamido-2-deoxy-D-glucose (GlcNAc), and sialic acid (NeuNAc) in the molar ratio of 2:1:1:1 and its structure can be represented by the following repeating unit:[Formula: see text]By cleavage of all the labile sialic acid end groups the incomplete type-III antigen is obtained which is structurally identical to the S. pneumoniae type-14 polysaccharide. Thus, the native type-III polysaccharide is serologically distinct from the incomplete type-III antigen by virtue of the former having determinants terminating in sialic acid and the latter in β-D-galactopyranose units. None of these latter determinants could be detected in streptococcal organisms grown under pH-controlled conditions (pH 7.0) or in rabbit antiserum made to these pH-controlled organisms. However, in antisera produced in rabbits to the same organisms grown without pH control (Lancefield procedures), antibodies to both types of determinant could be detected. This can be attributed to the removal of some of the masking sialic acid residues from the cell-associated native polysaccharide by degradative procedures which occur during these latter conditions.


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