Background: Vaginal infection is the commonest cause of genital symptoms and has obstetric and gynecological implications.
Aim: To compare the Nugent and Spiegel methods for the diagnosis of bacterial vaginosis (BV) and to analyze discordant specimens using Ison and Hay (Ison/Hay) criteria.
Material and methods: After discarding cases with Candidiasis, deficient specimens or those lacking bacteria, a total of 348 Gram-stained smears vaginal specimens received for the diagnosis of BV, were analyzed.
Results: Vaginal microbiota was classified as normal in 203 and 237 samples (58 and 68% of samples), according to Nugent and Spiegel criteria, respectively One hundred and five (30%) and 111 samples (32%), were classified as VB according to Nugent and Spiegel criteria, respectively. Both criteria were concordant in 308 samples (88.5%). The 40 (11.5%) discordant specimens were classified as intermediate microflora by the Nugent system and as normal or BV by Spiegel. Among these, the Ison/Hay procedure identified four categories of microbiota. Ten (25%) specimens were classified as grade II microbiota, confirming their categorization by Nugent as intermediate microbiota, six (15%) were classified in the III category, confirming the diagnosis of BV by Spiegel, 13 (32.5%) corresponded to the category III, that does not exist in the Nugent and Spiegel categorization systems. Finally, 11 specimens could not be assigned to one category due to microscopic limitations to distinguish bacterial morphotypes.
Conclusions: The systems proposed by Spiegel, Nugent and Ison/Hay are comparable for the diagnosis of BV. However, we recommend the use of Ison/Hay procedure to evaluate vaginal microbiota, due to its wider range of categories, allowing a better discrimination of the vaginal microbiota.