Comparison of monoclonal antibody methods and a ribosomal ribonucleic acid probe test forNeisseria gonorrhoeae culture confirmation

Abstract

Recently, a chemiluminescent nucleic acid probe test that specifically detects the ribosomal ribonucleic acid of Neisseria gonorrhoeae has been released for clinical laboratory use (AccuProbe Neisseria gonorrhoeae). In this study, three coagglutination tests (GonoGen I, Meritec GC, and GC Omni), the GonoGen II immunofiltration method and the Micro Trak Neisseria gonorrhoeae fluorescent monoclonal antibody test were compared with AccuProbe for identification of gonococci. Strains tested (n = 376) included 194 Neisseria gonorrhoeae, 82 Neisseria meningitidis, 32 Neisseria lactamica, 32 Neisseria species, 32 Moraxella catarrhalis, 2 Moraxella spp. and 2 Kingella denitrificans. The GonoGen I, Meritec GC and GC Omni coagglutination tests produced clearly positive results for 93.8%, 92.3% and 95.9% of the gonococci, respectively. The GonoGen II unequivocally identified 91.8% and the MicroTrak fluorescent antibody test identified 90.7% with 2+ or greater fluorescence. AccuProbe identified 100% of the gonococci tested. GonoGen I and GonoGen II were 98% specific, Meritec GC was 99% specific and the specificity of the GC Omni, MicroTrak fluorescent antibody and AccuProbe tests was 100%. While antibody-based tests were reliable when results were clearly interpretable, the AccuProbe was the only confirmatory test that was 100% accurate. Serotyping studies indicate that an array of beta-lactamase positive and negative gonococcal serotypes fail to react with the monoclonal antibody-based tests in general and with the fluorescent antibody test in particular.

The Laboratory Diagnosis of Neisseria gonorrhoeae

“…Both false-positive results (cross-reactions with other Neisseria species such as Neisseria meningitidis, Neisseria lactamica, N cinerea and K denitrificans) and false-negative results have been reported for the coagglutination tests (10,(12)(13)(14). Therefore, another test should be performed if the following conditions occur: the isolates suspected of being gonococci do not react with appropriate reagents or give equivocal results; positive results are obtained on isolates from extragenital sites in low-risk patients; and finally, positive results are obtained on isolates from children.…”