Rapid Detection of Sialidase Activity for the Diagnosis of Bacterial Vaginosis

Bacterial vaginosis (BV) is one of the most frequent causes of vaginal discharge in women during reproductive age worldwide. This disease is characterized by the replacement of the normal vaginal flora with an overgrowth of anaerobic bacteria most of them producing sialidase enzyme. BV is associated with an increased risk of adverse outcomes in pregnancy and susceptibility to several sexually transmitted diseases. In the present study, we evaluated the detection of sialidase activity by OSOM BVBlue test in association with routine microbial cultures and Nugent’s score, considered as the gold standard, for the diagnosis of bacterial vaginosis. Three vaginal swabs were collected from 352 women older than 12 years in age. A swab collected into Amies transport medium was employed for standard microbial cultures, a FLOQSwab for Gram stain, and a second FLOQSwab for the BVBlue test. According to Nugent’s score, BV frequency was 16.5 % (58 samples). The sensitivity of microbial culture and BVBlue test, when compared with Nugent’s score, was 69.8 % and 39.6 %, respectively. However, BVBlue test detected five cases with no bacterial growth in culture, whereas 14 samples with bacterial cultures positive for Gardnerella vaginalis showed a BVBlue test negative. The combination of microbial culture and BVBlue test increased the sensitivity to 75 % compared with Nugent’s score. In conclusion, BVBlue test alone appears not to be an efficient screening test, but, when associated with microbial cultures, can improve the diagnosis of BV