Evaluation of AMPLICOR Neisseria gonorrhoeae PCR using cppB nested PCR and 16S rRNA PCR.
Certain strains of Neisseria subflava and Neisseria cinerea are known to produce false-positive results with the AMPLICOR Neisseria gonorrhoeae PCR (Roche Diagnostic Systems, Branchburg, N.J.). The analytical sensitivity and analytical specificity of three PCR tests were assessed with 3 geographically diverse N. gonorrhoeae strains and 30 non-N. gonorrhoeae Neisseria spp. The sensitivities of the in-house nested cppB gene and the 16S rRNA PCR methods were greater than that of the AMPLICOR N. gonorrhoeae PCR with purified DNA from all 3 N. gonorrhoeae strains. Six of 14 clinical strains of N. subflava (1 from a vaginal swab, 5 from respiratory sites) produced false-positive AMPLICOR N. gonorrhoeae PCR results and were negative by the two other PCR methods. When applied to 207 clinical specimens selected from a population with a high prevalence ( approximately 9%) of infection, the results for 15 of 96 (15.6%) AMPLICOR-positive specimens and 14 of 17 (82.3%) AMPLICOR-equivocal specimens were not confirmed by the more sensitive nested cppB PCR method. Only 2 of 94 (2.1%) of AMPLICOR N. gonorrhoeae PCR-negative specimens from the same population tested positive by the nested cppB method. These results suggest that for this population the AMPLICOR N. gonorrhoeae PCR test is suitable as a screening test only and all positive results should be confirmed by a PCR method that is more specific and at least as sensitive. This study also illustrates that caution should be used when introducing commercially available nucleic acid amplification-based diagnostic tests into the regimens of tests used for populations not previously tested with these products.
Farrell
D J
DJ
Microbiology Section, Queensland Health Pathology Service Toowoomba Laboratory, Toowoomba, Queensland, Australia 4350. David_Farrell@health.qld.gov.au
D001425:Bacterial Outer Membrane Proteins / Q000235:genetics*; D004269:DNA, Bacterial / Q000032:analysis; D004275:DNA, Ribosomal / Q000032:analysis; D005069:Evaluation Studies as Topic; D005260:Female; D006069:Gonorrhea / Q000175:diagnosis* / Q000382:microbiology; D006801:Humans; D008297:Male; D009343:Neisseria / Q000145:classification / Q000235:genetics; D009344:Neisseria gonorrhoeae / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D016133:Polymerase Chain Reaction / Q000379:methods*; D011237:Predictive Value of Tests; D012336:RNA, Ribosomal, 16S / Q000235:genetics*; D012680:Sensitivity and Specificity; D014521:Urethra / Q000382:microbiology; D014556:Urine / Q000382:microbiology
D001425:Bacterial Outer Membrane Proteins; D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D012336:RNA, Ribosomal, 16S; C082716:cppB protein, Neisseria gonorrhoeae