Twenty-five isolates of nutritionally variant streptococci submitted to the Streptococcus Laboratory of the Center for Disease Control over a 2-year period were tested for growth requirements and for biochemical reactions. After they were recovered from storage in blood at -170 degrees C, all isolates grew within 48 h in both thioglycollate broth and Todd-Hewitt broth supplemented with 0.001% pyridoxal.HCl. They grew better in the latter, even though they all grew on unsupplemented infusion agar, anaerobe blood agar, and chopped meat-glucose medium. Biochemical patterns of the isolates resemble those of five viridans streptococcal species. Two isolates had patterns which did not resemble those of any viridans species. Biochemical reactions obtained with heart infusion broth base biochemicals and carbohydrate fermentation media compared favorably for an overall agreement rate of 86.5% for key tests. Lactic acid and acetic acid were the major fermentation products detected with gas-liquid chromatography.
A total of 155 strains of beta-hemolytic streptococci were serologically grouped by conventional techniques (Lancefield extraction and capillary precipitin testing) and by latex agglutination (LA). Agreement between conventional and LA techniques was 97% when the instructions of the manufacturer for the LA technique were followed. Agreement of 99% was obtained when modified autoclave extracts were used as antigens in the LA procedure. A total of 82 strains of non-beta-hemolytic streptococci were also tested by conventional, prescribed LA, and modified autoclave procedures. The agreement between conventional techniques and both LA procedures was 76%. However, when serological cross-reactions in the conventional grouping procedures were considered as errors, the accuracy of identification of both LA procedures was 88% among the non-beta-hemolytic strains. Of 13 strains of Streptococcus bovis, 10 did not react with the LA group D reagent but were serogroup D by conventional techniques. More S. bovis strains were grouped by the LA technique when extracts of 20 ml of broth cultures were used as antigens; however, cross-reactions were observed with non-group D strains when this technique was applied to them.
Outer membrane proteins (OMPs) were prepared from 20 previously established subtypes of Haemophilus influenzae type b. Proteins were separated by one-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis (11% acrylamide). Each lane in the gels contained two internal molecular weight standards. One central lane contained a range of molecular weight standards, which were Used to calculate a molecular weight curve for each gel. Migration distances of the OMPs were determined with a 5oft laser-scanning densitometer, and the distances were normalized by using the mean migration distances of the internal standards. The protein patterns of all subtypes were compared by a recently described method (B.
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