Affiliation:
1. Respiratory Diseases Branch, Centers for Disease Control and Prevention, Atlanta, Georgia 30333,1 and
2. Department of Nephrology, Hospital São João de Deus, Divinópolis, Brazil2
Abstract
ABSTRACT
The etiologic agent of a large 1998 outbreak of poststreptococcal acute glomerulonephritis (PSGN) in Nova Serrana, Brazil, was found likely to be a specific strain of
Streptococcus equi
subsp.
zooepidemicus
from contaminated cheese (S. Balter et al., Lancet 355:1776–1780, 2000). In the present study, we used a serologic screen for a known surface-exposed virulence factor to confirm the epidemiologic findings. Using primers flanking a previously characterized M-like protein gene (J. F. Timoney et al., Infect. Immun. 63:1440–1445, 1995), we amplified and sequenced the M-like protein (designated Szp5058) gene and found it to be identical among four independent acute-phase PSGN patient isolates. Convalescent-phase sera from 33 of 44 patients in the PSGN outbreak were found to contain antibodies highly reactive to a purified Szp5058 fusion protein, compared with 1 of 17 control sera (
P
< 0.0001), suggesting that Szp5058 was expressed during infection and further implicating this strain as the cause of the PSGN outbreak. The predicted signal sequence and cell wall association motif of Szp5058 were highly conserved with the corresponding sequence from
S. equi
subsp.
zooepidemicus
SzpW60, while the predicted surface-exposed portions differed markedly between these two proteins. The 5′ end of the
szp5058
gene, including its variable region, was identical to the
szp
gene from another strain associated with a previous PSGN outbreak in England (M. Barham et al., Lancet i:945–948, 1983), and the corresponding
szp
sequence found from the Lancefield group C type strain isolated from a guinea pig. In addition, the hypervariable (HV) portion of
szp5058
was identical to a previously published HV sequence from a horse isolate (J. A. Walker and J. F. Timoney, Am. J. Vet. Res. 59:1129–1133, 1998). Three other strains of
S. equi
subsp.
zooepidemicus
, including another strain previously associated with a PSGN outbreak, were each found to contain a distinct
szp
gene. Two of these
szp
genes had HV regions identical to
szp
regions from isolates recovered from different host species.
Publisher
American Society for Microbiology
Cited by
32 articles.
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