The presence of M protein in nontypeable group A streptococcal upper respiratory tract isolates from Southeast Asia.
Previous studies have suggested that group A streptococcal strains from southeast Asia, serotypically different from temporally related North American and European isolates, may represent unrecognized M serotypes. Sixty non-M typeable group A streptococcal upper respiratory tract isolates from Thailand were evaluated for the presence of M protein using a modification of the direct serum bactericidal test. Of them, 59 (98%) grew rapidly in human blood. Typeability by T agglutination and opacity factor production did not influence their growth in blood. It was concluded that these isolates produce M protein and likely represent previously uncharacterized M serotypes. Identification of such non-M typeable strains is important in understanding the epidemiology and pathogenesis of group A streptococcal infections and their sequelae in areas of the world where they remain a significant health problem and will also be necessary in the development of a vaccine with global efficacy.
Tran
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Department of Pediatrics, University of Minnesota Medical School, Minneapolis 55455.
Johnson
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Kaplan
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D000942:Antigens, Bacterial / Q000032:analysis*; D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins / Q000032:analysis*; D002352:Carrier Proteins; D002648:Child; D006801:Humans; D012137:Respiratory System / Q000382:microbiology; D012703:Serotyping; D013290:Streptococcal Infections / Q000145:classification / Q000276:immunology*; D013297:Streptococcus pyogenes / Q000145:classification* / Q000378:metabolism; D013785:Thailand
D000942:Antigens, Bacterial; D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D002352:Carrier Proteins; C014689:streptococcal M protein