Affiliation:
1. Institute of Experimental Medicine, Academy of Medical Sciences, Saint Petersburg 197376, Russia
2. Beijing Children′s Hospital Affiliated to Capital University of Medical Sciences, Beijing 100045, People's Republic of China
Abstract
ABSTRACT
A collection of 113 epidemiologically unrelated
Streptococcus agalactiae
strains were studied (group B streptococcus; GBS): they belonged to different serotypes and were isolated from pregnant women in China and Russia. The insertion sequence ISSa4 was found in 21 of 113 strains (18,6%). All of the strains with ISSa4 belonged to serotypes II and II/c and were characterized by the presence of IS
1381
and IS
861
as well as the absence of IS
1548
and GBSi1. All of the strains with ISSa4 possessed both
bca
and
bac
virulence genes coding for α and β antigens, respectively. Among 21 ISSa4-positive strains, 13 different
Hin
dIII patterns (D1 to D13) hybridizing with an ISSa4 probe were found. One of them (D13) contained a single
Hin
dIII hybridization fragment 6.5 kb in size that was found to be specific for all ISSa4-positive GBS strains. Multiple target sites for insertions of ISSa4 were identified and included a putative pathogenicity island, “housekeeping” genes, and intergenic regions, as well as the genes for hypothetical proteins. No significant similarity was observed in the sequences of the target genes for ISSa4 insertions, in the relative location of the target genes on the chromosome, or the biological functions of the encoded proteins. The possible significance of ISSa4-based differentiation of the strains and the presence of possible “hot spots” for insertions of ISSa4 in GBS genome are discussed.
Publisher
American Society for Microbiology
Subject
Molecular Biology,Microbiology
Cited by
10 articles.
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