The Presence of a Virulence Factor in Group A Streptococcal Acid Extracts II. The Enhancement of Virulence of Heterologous Streptococci and Other Organisms by These Extracts

Krasner, Robert I.; Heitmann, R.

doi:10.1093/infdis/118.1.39

Cited by 2 publications

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“…Similar type-specific inhibition of phagocytosis was observed in preopsonization inhibition tests with types 6 and 56 antisera and streptococci, respectively (Table 1). It should be noted also that preincubation of B. subtilis, E. coli, and M protein-negative streptococci with these M preparations did not inhibit their phagocytosis, suggesting that purified M protein does not enhance virulence of heterologous organisms as was suggested previously (8).…”

Section: Resultssupporting

confidence: 64%

“…Vacuolization and smudging of PMN suggested that phagocytosis of such non-type-specific antigen-antibody complexes produced PMN injury, thereby blocking phagocytosis of both homologous and heterologous streptococci. More recently, it was reported that streptococcal M protein extracts enhance the virulence not only of group A streptococci (7), but also of heterologous serogroups and other species of microorganisms (8). The latter investigators mixed their M protein extracts directly with fresh blood-streptococcus mixtures, as did Rothbard (12).…”

Section: Downloaded Frommentioning

confidence: 99%

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Type-Specific Inhibition of Preopsonization Versus Immunoprecipitation by Streptococcal M Proteins

Beachey

Cunningham

1973

Infect Immun

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Purified M protein of group A streptococci inhibits in vitro phagocytosis of bacteria nonspecifically when it is mixed directly with the test blood. We devised a method of preopsonization inhibition that avoids direct contact between the test blood and the opsonic inhibitory agent. Each of the M proteins tested by this method inhibited opsonization and phagocytosis of only homologous-type streptococci. Titration of the M antigen in various purified preparations demonstrated a clear dissociation between titers of type-specific precipitating M antigen and type-specific opsonic inhibitory M antigen. Since opsonization reflects protective antibody, assays of M protein based on reaction with opsonic antibody should reflect more accurately the presence of the type-specific M determinant involved in protective immunity against streptococcal infections.

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Section: Resultssupporting

confidence: 64%

Section: Downloaded Frommentioning

confidence: 99%

Type-Specific Inhibition of Preopsonization Versus Immunoprecipitation by Streptococcal M Proteins

Beachey

Cunningham

1973

Infect Immun

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“…Occurs both cell bound and extracellularly (20, Yes (42) Yes (40) Yes (40) No (40) Yes (38) Yes (27) Yes (28) No (14) No (29) Yes ( Yes (42) Yes'…”

Section: Data Unavailablementioning

confidence: 99%

Streptococcin A-FF22: Nisin-Like Antibiotic Substance Produced by a Group A Streptococcus

Tagg

Wannamaker

1978

Antimicrob Agents Chemother

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Streptococcin A-FF22 (SA) was shown to occur as both a cell-associated (SA-CA) and an extracellular (SA-EX) (40). In previous studies it has been established that SA is a proteinaceous substance of approximately 8,000 molecular weight (38) and that it is released extracellularly when the producer strain is grown in certain media, including Todd-Hewitt agar supplemented with 1% glucose (40) and tryptic soy broth (TSB) (38). SA has been found to be bactericidal for a susceptible group A streptococcus (38), and, although it is predominantly active against streptococci, the spectrum of its inhibitory action ranges over a variety of other gram-positive (but not gram-negative) bacteria (40). The genetic determinants of SA production and of producer cell immunity to SA appear to be plasmid-borne (42), and cotransduction of these determinants has been achieved by use of the virulent phage A25 (41).All of these characteristics of SA seem consistent with the rather loosely defined requirements for a substance to be classified within the subgroup of the antibiotics known as bacteriocins (37). The problem of differentiating some bacteriocin-like substances from other types of inhibitory bacterial products was emphasized to us when it was observed that the "classical" antibiotic nisin, produced by Streptococcus lactis (32), is in many respects very similar to SA, a substance we had considered to be a bacteriocin.In the present study, a cell-associated form of SA (SA-CA) was identified, and its relationship to the previously described extracellular SA (SA-EX) was examined. MATERIALS AND METHODSBacterial strains. The SA-producing (SAM) organism, group A streptococcus strain FF22 (M type 52, T type 3/13), the non-SA-producing derivatives of strain FF22, SPON 1 (M positive) and SPON 6 (M negative), and the sensitive indicator Staphylococcus aureus CIT have been used before (42).Strains of other bacterial species tested for susceptibility to SA were obtained from culture collections of the Departments of Microbiology and Pediatrics at the University of Minnesota and were selected from those used in a previous study (36). Additional M type 52 group A streptococci identified as strains 71-571, 71-230, 70-1562, 70-1563, and CV-830B

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The Presence of a Virulence Factor in Group A Streptococcal Acid Extracts II. The Enhancement of Virulence of Heterologous Streptococci and Other Organisms by These Extracts

Cited by 2 publications

References 0 publications

Type-Specific Inhibition of Preopsonization Versus Immunoprecipitation by Streptococcal M Proteins

Type-Specific Inhibition of Preopsonization Versus Immunoprecipitation by Streptococcal M Proteins

Streptococcin A-FF22: Nisin-Like Antibiotic Substance Produced by a Group A Streptococcus

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