Comparison of three major antigen detection methods for the diagnosis of Group B streptococcal sepsis in neonates

Hamoudi, Ayser C.; Marcon, Mario J.; Cannon, Harold J.; McClead, Richard E.

doi:10.1097/00006454-198311000-00004

Cited by 18 publications

(9 citation statements)

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“…Detection of GBS antigen in urine or other body fluids by latex particle agglutination (LPA) may facilitate the rapid diagnosis of GBS sepsis. GBS LPA assays have been reported to be 88 to 100% sensitive and 81 to 100% specific (2,4,6,8,10,12,13) and are commercially available in three assays: Wellcogen (Wellcome Diagnostics, Research Triangle Park, N.C.), Directigen (Becton-Dickinson Microbiology Systems, Cockeysville, Md. ), and Bactigen (Wampole Laboratories, Cranbury, N.J.).…”

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confidence: 99%

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: 99%

Comparison of commercially available group B streptococcal latex agglutination assays

1991

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“…Whether the Directigen GBS test is comparable to or better than Wellcogen Strep B LA will require side-by-side testing of clinical specimens. Previous reports concerning the latter indicate comparable sensitivity (90 to 100%) and specificity (88.7 to 96.4%) (2,5,6,8). Both assays provide for positive and negative latex controls to allow for immediate assessment of nonspecific reactions, and both require heating of urine specimens to provide for the best specificity (2).…”

Section: Discussionmentioning

confidence: 91%

“…In simultaneous testing of specimens, Directigen was significantly more sensitive than CIE (94.7 versus 68.4%) in identifying infants with culture proven GBS infection before culture results were available. Concentrated (10-fold) urine was the single best specimen for antigen detection by LA (100% sensitivity), a sensitivity which compares favorably with results from other LA reagents in the testing of 25to 50-fold-concentrated urine specimens (2,6,8). However, the use of Directigen has the potential advantage of evaluating patients with only small quantities of urine available for testing, since only a 10-fold concentration is required.…”

Section: Discussionmentioning

confidence: 98%

“…Because group B Streptococcus (GBS) is a frequent cause of life-threatening bacteremia and meningitis in neonates and young infants (1), rapid diagnostic methods for detection of the group B-specific polysaccharide antigen in body fluids have been developed. Among these methods, latex agglutination (LA) and slide coagglutination have had the best sensitivity (88 to 100%) (2,3,5,6,8,11,12), but a somewhat lower specificity (94 to 98%) (2,6,8,11) than countercurrent immunoelectrophoresis (CIE) (100%) (2,4,7,10). The hyperimmune rabbit antisera employed in these commercially available reagents are polyclonal and lot to lot variable with respect to GBS antibody titer.…”

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confidence: 99%

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Detection of group B streptococcal antigen in body fluids by a latex-coupled monoclonal antibody assay

Rench¹,

Metzger²,

Baker³

1984

J Clin Microbiol

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A commercially available latex agglutination reagent, Directigen (Hynson, Westcott & Dunning, Div. Becton Dickinson & Co., Baltimore, Md.), in which a murine monoclonal antibody to group B streptococcal (GBS) antigen is the active component, was evaluated by using body fluid specimens from 94 sick infants. Antigen was detected in one or more admission specimens from 18 of 19 (94.7%) infants with symptomatic GBS infection. In 15 patients with GBS meningitis, cerebrospinal fluid, serum, and 10-fold-concentrated urine specimens were positive in 87, 50, and 100%, respectively. GBS antigen was detected in 50% of unconcentrated urines, but in no sera from infants with nonmeningitic GBS sepsis. Among specimens from 27 infants with invasive infection due to organisms other than GBS and from 48 culture-negative sick infants, false-positive latex agglutination reactions occurred in only 4 (9.5%) urine specimens and in no cerebrospinal fluid or serum specimens. The 94.7% sensitivity and specificity of the Directigen GBS test indicate that it is a useful reagent for the rapid diagnosis of invasive GBS infection in young infants.

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“…The assay which has been evaluated the most is the Wellcogen Strep B LPA assay. The sensitivity of this assay was initially reported to range from 88 to 100% (4,11,15,17).…”

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confidence: 99%

Sensitivity and specificity of rapid diagnostic tests for detection of group B streptococcal antigen in bacteremic neonates

Greenberg

Ascher²,

Yoder³

et al. 1995

J Clin Microbiol

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Latex particle agglutination (LPA) testing for antigen to group B streptococcus (GBS) has been useful in the diagnosis of GBS sepsis in newborns. However, recent reports have demonstrated that the sensitivity of LPA assays may be as low as 27 to 54%. The purposes of the present study were to directly compare the abilities of four urine antigen assays to detect GBS antigen with clinical urine samples from neonates with GBS bacteremia and to evaluate the effect of the urine concentration on the sensitivities and specificities of these assays. Urine samples were collected serially from neonates with blood cultures positive for GBS or on admission from healthy full-term infants. One milliliter of urine was removed, and the remainder was concentrated to a volume of 1 ml. Unconcentrated samples were serially diluted with normal saline and were assayed to determine the highest dilution which would produce a positive test result. The Wellcogen, Bactigen, and Directigen LPA tests and ICON immunoassay were directly compared by using concentrated and unconcentrated urine specimens and urine specimens with known titers. A total of 94 urine specimens, including 61 concentrated and 75 unconcentrated specimens, from bacteremic infants were available for sensitivity testing, and 220 urine specimens from uninfected infants were available for specificity testing. There were significant differences in sensitivity among the four assays when they were performed on concentrated urine specimens, as follows: Directigen, 98%; Bactigen, 92%; ICON, 89%; Wellcogen, 68%. When the assays were performed on unconcentrated urine specimens, the Directigen (84%) and Bactigen (76%) assays were each significantly more sensitive than the ICON (59%) or Wellcogen (43%) assay. All four assays were significantly more sensitive in detecting GBS antigen in concentrated than in unconcentrated urine. The Directigen assay detected antigen in higher dilutions (geometric mean titer, 1:5) than the ICON (1:3), Bactigen (1:2), or Wellcogen (1:1) assay. The specificity was 99.5% for all four assays when concentrated urine was used and for the Bactigen, Directigen, and ICON assays when unconcentrated urine was used; the Wellcogen assay was 100% specific when unconcentrated urine was used. We conclude that there are significant differences in sensitivity but not specificity among the commercially available assays for the detection of GBS antigenuria when concentrated and unconcentrated urine specimens are tested. These differences in sensitivity may affect the abilities of clinicians to accurately diagnose GBS sepsis before culture results are available.

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Comparison of three major antigen detection methods for the diagnosis of Group B streptococcal sepsis in neonates

Cited by 18 publications

References 0 publications

Comparison of commercially available group B streptococcal latex agglutination assays

Comparison of commercially available group B streptococcal latex agglutination assays

Detection of group B streptococcal antigen in body fluids by a latex-coupled monoclonal antibody assay

Sensitivity and specificity of rapid diagnostic tests for detection of group B streptococcal antigen in bacteremic neonates

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