Fluorescent-Antibody Identification of Group A Streptococci from Throat Swabs

Moody, Max D.; Siegel, Alan C.; Pittman, Bertie; Winter, Carrie C.

doi:10.2105/ajph.53.7.1083

Cited by 44 publications

(16 citation statements)

References 5 publications

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“…All other organisms gave negative reactions (2+ or less) except for five of 340 group A and three of 41 group C streptococci. Crossreactions of group A conjugate with streptococcal groups C and G and S. aureus can usually be eliminated by absorption with group C cells or by a one-step inhibition either with group C antiserum or with pools of normal rabbit serum (20,21). Absorption of the B pool with group C cells, however, diminished the group B reaction to an unacceptable level.…”

Section: Resultsmentioning

confidence: 99%

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Identification of Group B Streptococci by Immunofluorescence Staining

Romero¹,

Wilkinson²

1974

Applied Microbiology

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Gamma globulin fractions of rabbit antisera prepared with whole cell vaccines of group B types Ia, Tb, II, and III and labeled with fluorescein isothiocyanate stained group B streptococci type specifically. Type Ic cells, which contain the Ta polysaccharide antigen of type Ta and the Ic protein antigen of type Tb, were specifically stained by both Ta and Tb conjugates. A group B conjugate pool (B pool) that contained one conjugate specific for each group B type at its predetermined titer gave positive fluorescent-antibody (FA) reactions (4+ intensity) with group B stock strains and negative FA reactions (less than 2+ intensity) with stock strains of streptococcal groups A, C through H, and K through U, viridans streptococci, Streptococcus pneumoniae, Staphylococcus aureus, Neisseria gonorrhoeae, and representative Enterobacteriaceae. Examination of 883 clinical isolates submitted to the Streptococcus Laboratory (Center for Disease Control, Atlanta, Ga.) for identification revealed a 99.1% agreement between FA and culture-precipitin methods. All 305 group B streptococci identified by culture-precipitin and six nonhemolytic group B streptococci missed initially by culture tests were identified correctly by FA. Results of cultural and FA methods in a double-blind study of 99 vaginal swabs agreed on 96 of 99 strains. Three nonhemolytic group B streptococci were identified first by FA and later confirmed by culture-precipitin tests.

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Section: Resultsmentioning

confidence: 99%

“…Cells representing homologous and heterologous types were allowed to react with one drop of each conjugate dilution for 15 to 30 min in a moist chamber at room temperature. The smears were washed and examined by established methods (20,21). Unstained smears and those stained with FITC-labeled normal rabbit globulin served as controls.…”

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Identification of Group B Streptococci by Immunofluorescence Staining

Romero¹,

Wilkinson²

1974

Applied Microbiology

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“…Until recently, in spite of extensive studies on group-and type-specific antigens using precipitation, immunofluorescence, counterimmunoelectrophoresis and other immunochemical techniques, the exact cytological location of these antigens remained uncertain. However, the finding that type antigens predominate in diagnostic immunofluorescence studies (Moody & Walker, 1966;Muller, 1967 ;Kubin et al, 1968;Smith, 1971;Romero & Wilkinson, 1974) suggests that these antigens are located on the cell surface covering the group antigen.…”

Section: Introductionmentioning

confidence: 99%

Immunoelectron Microscopic Study of the Location of Group-Specific and Protein Type-Specific Antigens of Group B Streptococci

Wagner¹,

Wagner²,

Kubín³

et al. 1980

Microbiology

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95The ultrastructural location of the group-specific polysaccharide and the type-specific protein antigens R and X of group B streptococci was studied by means of the direct immunoferritin technique. The group-specific antigen was located on the outer wall layer. The specificity of the reaction was proved by the inhibition of labelling after absorption of the antibody-ferritin conjugate with group B polysaccharide. On the other hand, the demonstration of the polysaccharide was not sterically hindered by protein type antigens. As with group A and C streptococci the group polysaccharide could be localized on both the outer and inner surfaces of isolated walls. The protein antigens R and X were also demonstrated on the wall surface. The specificity of the reaction was ensured by making use of the enzymic sensitivity of these antigens. The location of the R protein on long filaments protruding from the cell surface resembles that of M protein of group A streptococci. In contrast to the group polysaccharide both the R and X protein antigens are localized only on the outer surface of isolated walls.

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“…After overnight incubation at 350C in an atmosphere of 5% C02, these plates were examined for streptococcal colonies demonstrating beta-hemolysis. All such isolates were screened by the fluorescent antibody technique (3) to identify group A streptococci. Non-group A isolates were examined by precipitin testing methods (2) to determine the isolates of groups B, C, D, and G. Isolates identified as group B streptococci, which by colony count appeared to represent at least 25% of the throat flora, were suspended in 0.5 ml of sterile sheep erythrocytes.…”

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Change in Susceptibility of Group B Streptococci to Penicillin G from 1968 Through 1975

Severin

Wiley²

1976

Antimicrob Agents Chemother

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This report describes a study of 212 isolates of group B streptococci from sore throats over an 8-year period. A small but increasing percentage showed increased resistance to penicillin G when tested in an in vitro system.In 1938, Fry reported that group B, betahemolytic streptococci were causative agents of human disease (1). Subsequently, the syndromes of neonatal sepsis (5) and neonatal meningitis (4) due to group B streptococci were characterized.During the evaluation of a throat culture program serving physicians and dentists in our community, it was apparent that non-group A streptococci were being isolated from throat swabs of clinically ill individuals on a constant basis. Dacron swabs received from clinicians were routinely processed by culturing them on blood agar plates containing 5% sheep erythrocytes. After overnight incubation at 350C in an atmosphere of 5% C02, these plates were examined for streptococcal colonies demonstrating beta-hemolysis. All such isolates were screened by the fluorescent antibody technique (3) to identify group A streptococci. Non-group A isolates were examined by precipitin testing methods (2) to determine the isolates of groups B, C, D, and G. Isolates identified as group B streptococci, which by colony count appeared to represent at least 25% of the throat flora, were suspended in 0.5 ml of sterile sheep erythrocytes. These suspensions were stored at -20°C until antibiotic susceptibility tests could be performed. Before freezing, one of every 10 isolates was tested against penicillin G to determine a preliminary minimal inhibitory concentration (MIC). Representative isolates of group A streptococci (one per month) and group D streptococci (one per month) were similarly isolated, identified, tested, and stored. Later comparison with these preliminary MICs enabled us to determine the effects of time and freezing on the stored streptococci.Streptococcal isolates were tested against penicillin G in a twofold dilution series using Todd-Hewitt broth as the antibiotic diluent. The concentrations of penicillin G prepared ranged from 2.50 to 0.009 units/ml. The MIC for each isolate was measured in duplicate with the same lot number of culture medium and antibiotic. Each series was inoculated with a suspension of 104 colony-forming units of test isolate per ml. All cultures were incubated at 350C in an atmosphere of 5% CO2. Results were read after 24 h of incubation. When a duplicate series differed from the original, the isolate was restudied to establish the true MIC. Streptococci isolated during the years 1968 through 1973 were evaluated in an initial study. A second study evaluated the isolates of 1974 and 1975. A total of 212 group B streptococci isolates were studied during an 8-year period.

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Fluorescent-Antibody Identification of Group A Streptococci from Throat Swabs

Cited by 44 publications

References 5 publications

Identification of Group B Streptococci by Immunofluorescence Staining

Identification of Group B Streptococci by Immunofluorescence Staining

Immunoelectron Microscopic Study of the Location of Group-Specific and Protein Type-Specific Antigens of Group B Streptococci

Change in Susceptibility of Group B Streptococci to Penicillin G from 1968 Through 1975

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