Effectiveness of Gonozyme for detection of gonorrhea in low-risk pregnant and gynecologic populations.

The Gonozyme Diagnostic Kit (Abbott Laboratories, North Chicago, IL) was evaluated in a population at low-risk for gonorrhea. Two hundred seventy-two female patients, consisting of 152 obstetrical patients and 120 gynecologic patients attending a family-planning clinic, were tested for Neisseria gonorrhoeae by use of culture and Gonozyme testing of specimens from the endocervical canal. The average ages were 16.1 years for the obstetric patients and 17.8 years for the gynecologic patients. The overall sensitivity of Gonozyme as compared with culture was 60.8% (57.1% for obstetric patients and 62.5% for gynecologic patients); the overall specificity was 98.4%. An association was observed between the number of colony-forming-units (cfu) per plate and a positive Gonozyme test; specimens with less than 60 cfu/plate usually yielded a negative Gonozyme result. We conclude that Gonozyme is a highly specific test but its low sensitivity as compared with that of culture does not allow it to replace standard culture media for screening of low-risk women for infection with N. gonorrhoeae.

Evaluation of a ten-minute chromogenic substrate test for identification of pathogenic Neisseria species and Branhamella catarrhalis.

A ten-minute chromogenic substrate test was evaluated for its ability to rapidly identify pathogenic Neisseria spp. and Branhamella catarrhalis. Identifications obtained with this system were compared to those obtained using conventional procedures. The test correctly identified 98.9% of 90 Neisseria gonorrhoeae, 98.3% of 60 Neisseria meningitidis, 96.2% of 26 Neisseria lactamica, and 100% of 36 Branhamella catarrhalis strains. Eight Neisseria subflava strains that grew on modified Thayer-Martin agar were prolyl aminopeptidase positive and were misidentified as Neisseria gonorrhoeae. Other strains of saprophytic Neisseria spp. also reacted with the chromogenic substrates. The system was accurate and reliable for identifying the commonly encountered pathogenic species. In light of recent reports describing new species and atypical Neisseria strains, however, careful attention to the salient features of both common and atypical organisms is necessary for proper use of rapid enzymatic identification tests.