Involvement of enterotoxins G and I in staphylococcal toxic shock syndrome and staphylococcal scarlet fever.
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We investigated the involvement of the recently described staphylococcal enterotoxins G and I in toxic shock syndrome. We reexamined Staphylococcus aureus strains isolated from patients with menstrual and nonmenstrual toxic shock syndrome (nine cases) or staphylococcal scarlet fever (three cases). These strains were selected because they produced none of the toxins known to be involved in these syndromes (toxic shock syndrome toxin 1 and enterotoxins A, B, C, and D), enterotoxin E or H, or exfoliative toxin A or B, despite the fact that superantigenic toxins were detected in a CD69-specific flow cytometry assay measuring T-cell activation. Sets of primers specific to the enterotoxin G and I genes (seg and sei, respectively) were designed and used for PCR amplification. All of the strains were positive for seg and sei. Sequence analysis confirmed that the PCR products, corresponded to the target genes. We suggest that staphylococcal enterotoxins G and I may be capable of causing human staphylococcal toxic shock syndrome and staphylococcal scarlet fever. (+info)
Reactivity of rheumatic fever and scarlet fever patients' sera with group A streptococcal M protein, cardiac myosin, and cardiac tropomyosin: a retrospective study.
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Archived sera (collected in 1946) from acute rheumatic fever (ARF) and untreated scarlet fever and/or pharyngitis patients were reacted with streptococcal M protein, cardiac myosin, and cardiac tropomyosin. Except for very low levels to tropomyosin, antibodies to other antigens were not elevated in the sera of ARF patients relative to those of non-ARF patients, even though there was roughly equivalent exposure to group A streptococci. This suggests that antibodies to these molecules may not play a central role in the induction of ARF. (+info)
Molecular characterization of group A Streptococcus strains isolated during a scarlet fever outbreak.
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Forty group A streptococcus (GAS) isolates, recovered during a scarlet fever outbreak, were grouped based on their DdeI restriction profiles from emm amplicons. Twenty-seven isolates were identified by sequencing as emm2. The emm2 isolates showed the speA1, speB1, and speC1 alleles. Isolation of this GAS type from scarlet fever outbreaks is uncommon. (+info)
Major outbreak of toxic shock-like syndrome caused by Streptococcus mitis.
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Severe illness caused by viridans streptococci rarely occurs in immunocompetent hosts. Between December 1990 and May 1991, thousands of patients in the YangZi River Delta area of Jiangsu Province, China, suffered from scarlet fever-like pharyngitis. Fewer cases occurred in subsequent years with the same seasonality. Approximately half of the cases developed complications characteristic of streptococcal toxic shock-like syndrome (TSLS). Throat cultures yielded predominant growth of alpha-hemolytic streptococci. All cases admitted to Haian People's Hospital were investigated. Clinical specimens were collected, medical records were reviewed, and bacterial isolates were identified phenotypically and analyzed by 16S rRNA gene sequencing and pulsed-field gel electrophoresis (PFGE). Proteins were purified from culture supernatants by extraction, ammonium sulfate precipitation, and fast-protein liquid chromatography. Biological activities of protein components were determined by subcutaneous inoculation into rabbits. A total of 178 cases of non-beta-hemolytic streptococcal scarlet fever-like pharyngitis were studied. In 88 (79.3%) of 111 patients, oropharyngeal swab cultures grew morphologically identical alpha-hemolytic streptococci. A protein in culture supernatants was pyrogenic in rabbits, was mitogenic for splenocytes, and enhanced rabbit susceptibility to endotoxin challenge. The N-terminal amino acid sequence of this 34-kDa protein showed no homology with known Streptococcus pyrogenic exotoxins. The organism was identified as Streptococcus mitis based on biochemical and 16S rRNA sequence analyses. Representative outbreak isolates from 1990 to 1995 displayed identical PFGE patterns. This TSLS outbreak in southeastern China was caused by a toxigenic clone of S. mitis. An apparently novel toxin may explain the unusual virulence of this organism. (+info)
A NEW APPROACH TO BACTERIAL VACCINES.
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Immunizing antigens against only 10 bacterial diseases-cholera, diphtheria, paratyphoid, pertussis, plague, scarlet fever, staphylococcal disease, tetanus, tuberculosis and typhoid-have been licensed for sale in Canada and the United States. Convincing evidence of efficacy is available for only four of these-diphtheria and tetanus toxoids, and pertussis and typhoid vaccines.The principles which determine the efficacy of different immunizing antigens are not always the same. Toxoids, for example, stimulate the formation of antitoxin-producing mechanisms which can neutralize toxins produced by invading organisms, thereby rendering them harmless. Conversely, vaccines stimulate the formation of antibacterial mechanisms which stop the growth of organisms before they can produce disease.Use of enzyme-lysed vaccines for prevention of staphylococcal disease represents a new approach in vaccine research. Animal tests have shown lysed vaccines to be 10 to 100 times less toxic, and about eight times more effective, than whole bacterial vaccines. Studies with lysed vaccines for other diseases are now in progress. (+info)
Streptococcal erythrogenic toxin genes: detection by polymerase chain reaction and association with disease in strains isolated in Canada from 1940 to 1991.
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The presence of genes encoding pyrogenic exotoxins type A (speA), B (speB), and C (speC) and streptolysin O (slo) was determined by the polymerase chain reaction (PCR) to target specific sequences in 152 strains of group A streptococci. These included reference strains, representative M and T type strains, and strains associated with scarlet fever and pharyngitis collected between 1940 to 1991 and included strains from patients with severe invasive streptococcal infections. PCR amplicons were detected by agarose gel electrophoresis, and specificity was established by restriction fragment analysis. The frequency of occurrence for each target gene among all strains tested was 33.6% for speA, 99.3% for speB, 28.9% for speC, and 100% for slo. Strains of non-group A streptococci, recognized toxigenic bacterial pathogens, and pneumolysin-producing Streptococcus pneumoniae strains were negative for all targeted gene sequences. Detection limits in the PCR were found to be 100 pg of total nucleic acids for the speB and speC genes and 1 ng for the speA and slo genes. Isolates associated with scarlet fever, pharyngitis, and severe invasive infections showed statistically significant differences in the presence of speA, with scarlet fever strains having the highest association (81.3%), severe infections the next highest association (42.9%), and pharyngitis the lowest association (18.4%). Although no significant differences were observed in speC frequencies in isolated associated with the three disease categories, a genotype of speB slo was significantly higher in isolates associated with pharyngitis (54.1%) than in strains associated with scarlet fever (18.8%) or severe invasive disease (23.8%). Streptolysin O targets were present in all the isolates tested, and only a single strain (T-11-M-11) was devoid of targeted speB sequences, thereby demonstrating that neither speB nor slo is associated with any particular clinical presentation. (+info)
Molecular analysis of group A streptococcal isolates associated with scarlet fever in southern Taiwan between 1993 and 2002.
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Collected between 1993 and 2002 at a Taiwanese university hospital, 77 group A streptococcus isolates associated with scarlet fever were grouped by emm typing and pulsed-field gel electrophoresis. The predominance of an emm1 clone before 1996 and the presence of genetically diverse emm1 and emm4 strains thereafter were found. (+info)
Varicella complicated by scarlet fever.
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We report a 3-year-old boy with varicella complicated by cellulitis and scarlet fever. He developed a typical rash of scarlet fever following the onset of varicella. Streptococcus pyogenes was isolated from the ulcers due to varicella. The present case suggests that scarlet fever may rarely develop following varicella and should be considered in children with complicated varicella. (+info)