Fluorescent monoclonal antibody compared with carbohydrate utilization for rapid identification of Neisseria gonorrhoeae

Abstract

A commercially available fluorescein-conjugated monoclonal antibody (MAb) (Syva Co., Palo Alto, Calif.; Genetic Systems, Seattle, Wash.) against Neisseria gonorrhoeae was compared with a standard cystine Trypticase agar (CTA) sugar utilization method and with three rapid carbohydrate utilization tests, including the Minitek (BBL Microbiology Systems, Cockeysville, Md.), Neisseria-Stat (Richardson Scientific, Dallas, Tex.), and Neisseria-Kwik (Micro-Biologics, St. Cloud, Minn.) systems for the identification of Neisseria species. The MAb correctly identified ail 86 clinical isolates of N. gonorrhoeae. Of these 86 isolates, 28 were found later (48 h after the initial inoculation) to be contaminated with non-Neisseria bacteria. In the other four test systems studied, the identification rates for pure and contaminated N. gonorrhoeae cultures were, respectively, as follows: CTA sugars, 88 and 32%; Minitek, 67 and 50%; Neisseria-Stat, 97 and 96%; and Neisseria-Kwik, 80 and 74%. The MAb did not identify any of the 50 nongonoccocal Neisseria isolates tested. The most expensive test system was the MAb, followed by the Neisseria-Kwik, Minitek, Neisseria-Stat, and CTA sugars systems. The MAb appears to be a rapid and accurate method to identify in vitro isolates of N. gonorrhoeae.

Two confirmatory tests for identification of Neisseria gonorrhoeae from primary culture

“…We found the Syva test sufficiently sensitive and specific to perform routinely on primary genital cultures. Although the specificity of Syva has been verified in other studies (3,6), false-negatives have been documented (5; J. S. Lewis, J. W. Biddle, M. E. Shepherd, and J. S. Knapp, Abstr. Seventh Int.…”

Historical perspectives and identification of Neisseria and related species.

“…Some problems may be encountered when rapid tests are used to determine acid production from carbohydrates by N. gonorrhoeae. Acid reactions by some strains of N. gonorrhoeae and N. meningitidis may not be easily interpreted in some tests (99). Some strains of N. gonorrhoeae, including those that belong to the AHU auxotype, are weak producers of acid from glucose and appear to be glucose negative (72).…”

“…Monoclonal antibody diagnostic reagents have generally been highly specific and sensitive for N. gonorrhoeae when used to identify isolates from high-risk patients in primary cultures on gonococcal selective media (23,30,66,67,70,99) A. C. Kuritza, C. Chapis, P. Gallo, and S. C. Edberg, Abstr. Annu.…”

“…Nongonococcal Neisseria spp. have not reacted with the Microtrak FA reagent (30,66,99). Occasionally, however, strains of N. gonorrhoeae have not reacted in this test (Lewis et al, Abstr.…”

Rapid identification of pathogenic neisserias using the Identicult-Neisseria test

“…Commercially available rapid methods for the culture confirmation of Neisseria gonorrhoeae include : immunological tests such as fluorescent monoclonal antibody staining (Ison el al. 1988;Welch and Cartwright 1988) and coagglutination using monoclonal antibodies raised to epitopes on the gonococcal outer membrane protein I (Young and Moyes 1989); carbohydrate utilization tests for the detection of preformed enzymes (Young et al 1976); radiometric detection of '4C-labelled gas production (Boyce et al 1985); and more recently nucleic acid hybridization tests using a chemiluminescent single-stranded DNA probe (Naher et al 1989;Sprott et al 1989;Ridderhof et a1 1990;Young and Moyes 1993).…”