Evaluation of a Fast Test to Identify the Presence of Proline Aminopeptidase in Women With Bacterial Vaginosis

Objective: The purpose of this study was to evaluate the activity of proline aminopeptidase by a rapid paper strip test in women with bacterial vaginosis (BV). Methods: Vaginal secretions of 1,387 voluntary patients attending the Obstetrics and Gynecology Infectious Diseases Clinic at Juárez Hospital of Mexico City were collected and examined. Patients were assigned into 2 groups: 483 with BV according to clinical and laboratory criteria and 604 without BV as the control group. For the purposes of this study, 300 patients with trichomonas and/or yeast were excluded from the BV group. The strips were prepared by using L-proline β-naphthylamide and L-proline p-nitroanilide as the substrates to detect proline aminopeptidase activity in concentrated vaginal secretions. In parallel, all samples were also analyzed with the standard methods in microplates containing either sustrate as a control of the rapid strip test. The test was interpreted after 3–5 min of incubation. Results: The results in the strip and microplate assays were similar in 95% of the samples. Sensitivity was 91.7% and specificity was 94.2%; probability of BV if the test is positive was 92.6% and negative predictive value was 93.4%. Conclusions: These findings indicate that this aminopeptidase rapid strip assay provides a 3–5 min identification of activity of the enzyme in women with BV. The procedure is a rapid, non-expensive, sensitive, and useful test at the gynecologic clinic.