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A T antigen preparation free of trypsin was obtained by application of CNBr-Sepharose linked to pure trypsin. Purification on an ion exchange chromatography column results in an electrophoretically homogeneous preparation of T protein.
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OBJECTIVE: To evaluate the occurrence of cases of acute rheumatic fever (ARF) in western Pennsylvania although there has been a marked reduction of cases of ARF in the United States overall. STUDY DESIGN: From 1994 to 2003, the cases of ARF evaluated at Children's Hospital of Pittsburgh were reviewed. In addition, throat cultures were performed on a subset of these children and their family members beginning in 1995. Molecular typing was performed on isolates of the group A streptococcus (GAS) recovered, using field inversion gel electrophoresis (FIGE) and emm typing. RESULTS: There were 121 new cases of ARF from 1994 to 2003. Of these, 57% were male. The median age was 10 years. The majority of children (57%) had carditis with or without another manifestation of ARF. The results of throat cultures were available for 231 persons; 36% (30/84) of the children with ARF and 14% (20/147) of family members were positive for GAS. Eight emm types were observed (emm 1, 2, 6, 12, 18, 28, 75, and 89). Data suggest that emm type 12 may be a rheumatogenic strain. CONCLUSION: ARF remains a problem in western Pennsylvania. Identification of emm types associated with cases should enlighten vaccine development.
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The orientation of lipoteichoic acid (LTA) molecules on the surface of bacterial cells undoubtedly is determined by the ability of the LTA, during its transit through the cell wall, to bind via its polyglycerophosphate backbone or its glycolipid moieties to other constituents of the cytoplasmic membrane and the cell wall. We have investigated the possibility that LTA may become anchored to the cell surface by binding through its polyanionic backbone to positively charged regions of cell wall proteins. LTA was found to prevent the precipitation of partially purified HCl extracts of several strains of streptococci as well as a structurally defined streptococcal M protein molecule (pep M24) in 83% solutions of ethanol. The formation of complexes between LTA and M protein was demonstrated further by immunoelectrophoresis of pep M24 protein with increasing concentrations of radiolabeled LTA and by using antiserum against pep M24 to develop precipitin arcs. Pep M24 electrophoresed alone produced a single precipitin arc close to the origin. In contrast, when electrophoresed as a mixture with LTA or deacylated LTA, the M protein produced a second precipitin arc toward the anode coinciding with the area of migration of the radioactive LTA. Increasing concentrations of LTA or deacylated LTA shifted increasing amounts of the pep M24 antigen to the region of the second arc. Maleylation of M protein to block the positively charged free amino groups before mixing it with LTA prevented the formation of complexes. The complexes formed by the M protein with LTA, but not with deacylated LTA, showed the capacity to bind bovine serum albumin; LTA had been shown previously to bind to the fatty acid binding sites on bovine serum albumin. These results indicate that the LTA molecule is able to bind via its polyanionic backbone to positively charged residues of surface proteins of cells of S. pyogenes. The implications of such interaction as to the orientation of LTA molecules on the surface of cells of S. pyogenes are discussed.
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We investigated the epidemiology and clinical features of invasive S. pyogenes infection in a pediatric population over a 7-year period (1984-90) by retrospective review. An increasing frequency in invasive infections had occurred (0-11.81/10,000 admissions). A large proportion (48%) of these were orthopedic infections. An epidemic strain was typed as M1T1. This increase appears to have occurred in the context of an overall increase in S. pyogenes infections ("scarlet fever" 1.47-11.22/10,000 outpatients; "strep throat" 4.41-46.54/10,000 outpatients).
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A 30-year-old female with mild asthma presented with high fever, hypotension, pleuritic chest pain, vomiting and diarrhea. Chest radiograph showed consolidation of the right upper lobe, and S. pyogenes was cultured from blood and sputum. Following initial rapid recovery the patient relapsed ten days after antibiotics were ceased, with rapid development of a large abscess cavity. Clinical improvement occurred following reinstitution of treatment including intravenous penicillin. Progressive radiological resolution eventuated during outpatient follow-up. This case demonstrates that S. pyogenes pneumonia may occur without an antecedent viral infection or major predisposing condition, cause rapid cavitation despite antiobiotic therapy and resolve satisfactorily with prolonged penicillin therapy.
The effects of cellular subfractions of S. pyogenes on phagocytosis from neutrophils were studied. Cell-walls and membranes were found to stimulate the phagocytosis at low concentrations: at immediately higher doses they show to have a citotoxic effect.