Virulence properties of type VII Streptococcus agalactiae (group B streptococci) and immunochemical analysis of capsular type polysaccharide

Hunolstein, Christina von; Parisi, Laura; Tissi, Luciana; Recchia, Simona; Alfarone, Giovanna; Nicolini, Laura; Volpe, Corrado; Wagner, Barbara; Motlová, J; Orefici, Graziella

doi:10.1099/00222615-48-11-983

Cited by 9 publications

(5 citation statements)

References 36 publications

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“…Streptococcus pyogenes (Moses et al, 1997), Streptococcus suis (Charland et al, 1996;Jacques et al, 1990), Streptococcus uberis (Leigh et al, 1990), Streptococcus pneumoniae (De Velasco et al, 1995) and Streptococcus agalactiae (Kubin & Ryc, 1988 ;Von Hunolstein et al, 1993). The present study thus confirms that the presence of a capsule is a common feature in streptococci.…”

Section: Discussionsupporting

confidence: 79%

Ultrastructure of surface components of Streptococcus gallolyticus (S. bovis) strains of differing virulence isolated from pigeons

et al. 1999

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Virulence of Streptococcus ga//o/yticus (S. bovis) strains isolated from pigeons is associated with the presence of the extracellular proteins A, TI, T2 and T3. Based on the presence or absence of these proteins, six supernatantphenotypes are distinguished. Experimental infection studies have indicated that strains belonging to the A'TI, A+TI, A+T2 and A+T3 groups are highly virulent for pigeons, strains belonging to the A'T3 groups are moderately virulent and A'T2 strains are of low virulence. In this study the surface structure of 15 pigeon 5. ga//o/yticus strains representing high, moderate and low virulence supernatant-phenotypes was examined by electron microscopy. The presence of capsular material was determined by transmission electron microscopy after polycationic ferritin labelling and immunostabilization. Capsules from cells labelled with polycationic ferritin were usually thicker than those from cells exposed to antiserum. The capsule of the virulent strains had a regular, continuous appearance whilst irregularity of the capsule was a characteristic of the low virulence A'T2 strains. Negative staining revealed the presence of fimbriae in all strains belonging to the high virulence A'TI, A+TI, A+T2 and A+T3 supernatant groups and in one strain of the moderately virulent A'T3 group. The fimbriae were thin, flexible structures with a diameter of approximately 3-4 nm and a length of up to 700 nm. Fimbriae as described above were absent in two other A'T3 strains examined and in the low virulence A'T2 strains. Results from this study indicate that morphological differences in surface structure exist among virulent and low virulence pigeon S. ga//o/yticus strains, and that the capsule and/or fimbriae are possibly involved in virulence.

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Section: Discussionsupporting

confidence: 79%

Ultrastructure of surface components of Streptococcus gallolyticus (S. bovis) strains of differing virulence isolated from pigeons

et al. 1999

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“…These include serotyping (16)(17)(18)(19)(20), restriction fragment length polymorphism analysis (21), ribotyping (22), pulsed-field gel electrophoresis (23), multilocus enzyme electrophoresis (24,25), analysis of randomly amplified polymorphic DNA (26), amplified cps restriction polymorphism analysis (27) and multilocus sequence typing (MLST) (28).…”

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confidence: 99%

DNA Microarray-Based Typing of Streptococcus agalactiae Isolates

Nitschke¹,

Slickers²,

Müller³

et al. 2014

J Clin Microbiol

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c Streptococcus agalactiae frequently colonizes the urogenital tract, and it is a major cause of bacterial septicemia, meningitis, and pneumonia in newborns. For typing purposes, a microarray targeting group B streptococcus (GBS) virulence-associated markers and resistance genes was designed and validated with reference strains, as well as clinical and veterinary isolates. Selected isolates were also subjected to multilocus sequence typing. It was observed that putative typing markers, such as alleles of the alpha-like protein or capsule types, vary independently of each other, and they also vary independently from the affiliation to their multilocus sequence typing (MLST)-defined sequence types. Thus, it is not possible to assign isolates to sequence types based on the identification of a single distinct marker, such as a capsule type or alp allele. This suggests the occurrence of frequent genomic recombination. For array-based typing, a set of 11 markers (bac, alp, pil1 locus, pepS8, fbsB, capsule locus, hylB, abiG-I/-II plus Q8DZ34, pil2 locus, nss plus srr plus rogB2, and rgfC/A/D/B) was defined that provides a framework for splitting the tested 448 S. agalactiae isolates into 76 strains that clustered mainly according to MLST-defined clonal complexes. There was evidence for region-and host-specific differences in the population structure of S. agalactiae, as well as an overrepresentation of strains related to sequence type 17 among the invasive isolates. The arrays and typing scheme described here proved to be a convenient tool for genotyping large numbers of clinical/veterinary isolates and thus might help obtain insight into the epidemiology of S. agalactiae.

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“…Of the nine serotypes described so far, the types Ia, Ib, II, III, and V are responsible for the majority of invasive human GBS diseases. The chemical structures of these polysaccharides have already been determined [4][5][6][7][8][9][10][11] (Fig. 1).…”

Section: Introductionmentioning

confidence: 99%