Trimethylamine and trimethylamine oxide levels in normal women and women with bacterial vaginosis reflect a local metabolism in vaginal secretion as compared to urine.

The smell of rotten fish is one of the characteristics of bacterial vaginosis (BV), and is due to trimethylamine (TMA). Trimethylamine can be found in human urine, although most of it occurs as the nonvolatile oxide (TMAO) form. The fraction TMA/TMAO can be expected to be the same in different body fluids if no local production of TMA occurs. In women with BV, TMAO in the vaginal fluid is expected to be chemically reduced by the local bacterial flora to the much more odorous TMA. We have therefore studied the local vaginal production of TMA in vaginal secretion compared to the general TMA-TMAO metabolism that was measured in urine using gas chromatography. Both vaginal fluid and random urine samples were collected from women, with and without BV, attending a Swedish clinic for sexually transmitted diseases, and these samples were analyzed for TMA and TMAO. The results show that a local production of TMA occurs in the vagina that is not part of the general metabolism of TMA-TMAO.

Analysis of bacterial vaginosis-related amines in vaginal fluid by gas chromatography and mass spectrometry.

The presence of various amines in vaginal fluid from women with malodorous vaginal discharge has been reported before. The investigations have used several techniques to identify the amines. However, an optimized quantification, together with a sensitive analysis method in connection with a diagnostic procedure for vaginal discharge, including the syndrome of bacterial vaginosis, as defined by the accepted "gold standard," has not been done before. We now report a sensitive gas chromatographic and mass spectrometric method for identifying the amines isobutylamine, phenethylamine, putrescine, cadaverine, and tyramine in vaginal fluid. We used weighted samples of vaginal fluid to obtain a correct quantification. In addition, a proper diagnosis was obtained using Gram-stained smears of the vaginal fluid that were Nugent scored according to the method of Nugent et al. (R. P. Nugent et al., J. Clin. Microbiol., 29:297-301, 1991). We found that putrescine, cadaverine, and tyramine occurred in high concentrations in vaginal fluid from 24 women with Nugent scores between 7 and 10. These amines either were not found or were found only in very low concentrations in vaginal fluid from women with Nugent scores of 0 to 3. There is a strong correlation between bacterial vaginosis and the presence of putrescine, cadaverine, and tyramine in high concentrations in vaginal fluid.