Detection of group B streptococcal antigens in amniotic fluid of rhesus monkeys

Hemming, Val G.; London, William T.; Smith, L P; Curfman, Blanche; Fischer, GeraldW.; Sever, John L.

doi:10.1128/jcm.17.6.1127-1131.1983

Cited by 8 publications

(5 citation statements)

References 22 publications

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“…Although similar studies have been published or have appeared as abstracts, the present study utilizes the current modified Directigen reagent and challenges all three products with identical test solutions. Our results comparing the three assays with group-specific antigen in urine and serum are consistent with findings of Hemming et al (9) but different from the findings of Wasilauskas and Hampton (14). The method of preparation of the antigen solutions was not noted in the other investigations comparing the three GBS LPA assays, and thus the limits of sensitivities for the antigen preparations may not be comparable.…”

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confidence: 57%

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Comparison of commercially available group B streptococcal latex agglutination assays

1991

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Detection of group B streptococcus (GBS) antigen in urine by latex particle agglutination (LPA) may facilitate the rapid diagnosis of GBS sepsis. We sought to compare three commercial LPA assays with specimens that were spiked with type-specific antigen, group-specific antigen, or type III organisms. There were sensitivity differences between the assays, but the Bactigen assay performed best, detecting as little as 1 ng of GBS group-specific antigen per ml in urine and as few as 105 CFU of GBS type III organisms per ml in urine, serum, and cerebrospinal fluid.

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confidence: 57%

“…Tube dilutions (1:10) were serially made to a concentration of 10-11 g. Streptococcal strains. GBS strains SS878 and Norris (virulent, type III clinical isolates) were prepared as previously described (9). The bacterial concentration was determined spectrophotometrically and then adjusted to a final concentration of 108 bacteria per ml in 0.9% saline.…”

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confidence: 99%

Comparison of commercially available group B streptococcal latex agglutination assays

1991

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“…It infection. On the basis of the sensitivity of latex agglutination elevant that the majority of cell-associated type-and reagents used for diagnostic purposes (14), it can be assumed ecific antigens are covalently linked to peptidoglycan that 62 to 83% of neonates with early-or late-onset GBS It is po cally witb may be r group-spx disease have circulating group-specific antigen levels of >125 ng/ml (17).…”

Section: (0) Are Unencapsulated Mutants Of Strains Coh1 (U) Andmentioning

confidence: 99%

Induction of tumor necrosis factor alpha by the group- and type-specific polysaccharides from type III group B streptococci

et al. 1994

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Previous studies suggested that circulating tumor necrosis factor alpha (TNF-a) may have a pathophysiologic role in experimental neonatal sepsis induced by group B streptococci (GBS). This study was undertaken to investigate the ability of the type III and group-specific polysaccharides of GBS to induce TNF-a production and TNF-a-dependent lethality in neonatal rats. The cytokine was detected in plasma samples by the L929 cytotoxicity assay. Intracardiac injections of either polysaccharide induced dose-dependent, transient elevations in plasma TNF-a levels that returned to baseline values after 5 h. The group-specific antigen induced significantly higher mean peak TNF-a levels than the type III antigen (125 ± 47 versus 44 ± 15 U/ml with 70 mg/kg of body weight). Glycogen (70 mg/kg), used as a negative control, did not induce TNF-a. The lipopolysaccharide-neutralizing agent polymyxin B did not decrease TNF-a levels induced by either polysaccharide, ruling out contamination with endotoxin as a possible cause of TNF-ot induction. Fifty percent lethal doses of the type III and group-specific antigens given as intracardiac injections were 105 and 16 mg/kg, respectively. Salmonella endotoxin, used as a positive control, had a 50%o lethal dose of 0.1 mg/kg. The lethal activities of GBS polysaccharides, as well as endotoxin, were completely prevented by pretreatment of neonatal rats with the respective specific antibodies or anti-murine TNF-a serum. To assess the relative importance of the type-specific substance in TNF-aL induction by whole bacteria, two unrelated GBS transposon mutants devoid of only the type-specific capsular polysaccharide (COH1-13 and COH31-15) were employed. Each of the heat-killed unencapsulated mutants was able to produce plasma TNF-a level elevations or TNF-ea-dependent lethality but was significantly less efficient in these activities than the corresponding encapsulated wild-type strain. These data suggest that the presence of type-specific material on GBS is not necessary for the stimulation of TNF-a production. Type III capsular polysaccharide, however, can significantly increase the ability of GBS to induce TNF-a. Further studies will be needed to assess the importance of TNF-a induction by the group-and type-specific antigens in the pathophysiology of GBS disease.

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“…A variety of methods have been reported to reduce this nonspecific activity in clinical specimens, including heat (1. 6, 7, 13, 16, 23, 24), EDTA (6,7,9,11), N-acetyl-L-cysteine (26), EGTA (12), and dithiothreitol (2, 10, 22). Other investigators have reported the use of either trichloroacetic acid or EDTA to extract bacterial antigens (14,15,18), polyanetholesulfonic acid to precipitate serum protein (20,21), and EDTA to enhance the sensitivity of agglutination reactions (12).…”

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confidence: 99%

“…Rheumatoid and other nonspecific factors have been noted to interfere with LA tests (3,9,12,18,19,25), and several methods have been reported to be helpful in removing interfering factors (6,7). In a previous study, we reported that serum and amniotic fluid could not be used directly with Wellcogen Strep B reagents and that a modification to the method of the manufacturer was necessary (11). We also reported that the use of the serum buffer in the original Bactigen Haemophilus influenzae type b kit did not completely eliminate NSA (L. P. Smith, K. W. Hunter, and G. W. Fischer, Abstr.…”

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Improved detection of bacterial antigens by latex agglutination after rapid extraction from body fluids

Smith¹,

Hunter²,

Hemming³

et al. 1984

J Clin Microbiol

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Nonspecific agglutination of antibody-coated latex particles, unrelated to the presence of specific bacterial antigens, is a major difficulty with commercial latex particle agglutination tests. Rheumatoid and other factors are known to interfere with latex tests. We studied the use of six chelating, reducing, and anticoagulatory reagents in a rapid extraction of antigen procedure to free heat-stable antigens of Haemophilus influenzae type b and group B streptococcus which had been added to human sera. We also screened sera for the incidence of nonspecific agglutination from the three following groups: 123 patients with positive serology tests, 112 hospitalized patients, and 87 blood donors. The rapid extraction of antigen procedure involved a 1:4 dilution of the sera with each of the six reagents, incubation at 100°C for 3 min, and centrifugation at 13,000 x g for 5 min. Two commercial latex kits were tested (Bactigen and Wellcogen). Nonspecific agglutination was entirely eliminated by each of the six extraction reagents. Sera from 52% of the patients with positive serology tests, 29% of the hospitalized patients, and 28% of the blood donors showed nonspecific agglutination with Bactigen before extraction. Nonspecific agglutination was eliminated in all but one sample after the rapid extraction of antigen procedure. This simple, rapid extraction procedure eliminated nonspecific reactions in cerebrospinal fluids and amniotic fluids and reduced this problem in urines and sera with each commercial kit used on clinical specimens.

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Detection of group B streptococcal antigens in amniotic fluid of rhesus monkeys

Cited by 8 publications

References 22 publications

Comparison of commercially available group B streptococcal latex agglutination assays

Comparison of commercially available group B streptococcal latex agglutination assays

Induction of tumor necrosis factor alpha by the group- and type-specific polysaccharides from type III group B streptococci

Improved detection of bacterial antigens by latex agglutination after rapid extraction from body fluids

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