Wet mount microscopy reflects functional vaginal lactobacillary flora better than Gram stain.

AIM: The status of vaginal lacto-bacillary flora, an indicator of possible genital infection and pregnancy complications, can be assessed on wet mount or Gram stained specimens. The former is quick, the latter more routine. The accuracy of the two preparative techniques to detect normal vaginal lacto-bacillary microflora was compared for 646 patients. The effect of delay in transport medium before Gram staining was also investigated. METHODS: Patients presented with infectious vaginitis or for a routine prenatal visit. After placement of a speculum, duplicate smears were taken from the upper vaginal vault and examined fresh or after Gram staining. Lacto-bacillary grades from both methods were compared with lactate concentration in vaginal rinses. In a subgroup of 238 patients, Gram staining was performed both on fresh smears and those that had been transported in Stuart's growth medium. RESULTS: Higher lacto-bacillary grades (more disrupted flora) were diagnosed 2.9 times more frequently on Gram stained specimens than on wet mounts (p < 0.0001), a difference even more pronounced after transport in Stuart's medium (relative risk, 4.2; p < 0.0001). Lacto-bacillary grades assessed on wet mounts correlated better with vaginal lactate concentration than those assessed on Gram stains. CONCLUSIONS: Easier recognition of lacto-bacillary morphotypes on wet mounts than on Gram stains might result from the loss of lactobacilli by the process of fixation or Gram staining. Wet mount microscopy of vaginal smears for assessment of lacto-bacillary grades, rather than Gram staining, is strongly recommended.

Pathogenesis of abnormal vaginal bacterial flora.

OBJECTIVE: This study was undertaken to determine the relationships between microscopy findings on wet mounts, such as lactobacillary grade or vaginal leukocytosis, and results of vaginal culture, lactate and succinate content of the vagina, and levels of selected cytokines. STUDY DESIGN: In a population of 631 unselected women seeking treatment at an obstetrics and gynecology outpatient clinic, vaginal fluid was obtained by wooden Ayre spatula for wet mounting and pH measurement, by high vaginal swab for culture, and by standardized vaginal rinsing with 2 mL 0.9% sodium chloride solution for measurements of lactate, succinate, interleukin 1beta, interleukin 8, leukemia inhibitory factor, and interleukin 1 receptor antagonist concentrations. Lactate and succinate levels were measured by gas-liquid chromatography and the cytokine concentrations were measured by specific immunoassays. Both univariate analysis (Student t test, Welch test, chi(2) test, and Fisher exact test) and multivariate regression analysis (Cox analysis) were used. RESULTS: Increasing disturbance of the lactobacillary flora (lactobacillary grades I, IIa, IIb, and III) was highly correlated with the presence of Gardnerella vaginalis, Trichomonas vaginalis, enterococci, group B streptococci, and Escherichia coli. Vaginal pH and interleukin 8 and interleukin 1beta concentrations increased linearly with increasing lactobacillary grade, whereas lactate concentrations and the presence of epithelial cell lysis decreased. A similar pattern of associations with increasing leukocyte count was clear, but in addition there was an increase in leukemia inhibitory factor concentration. Multivariate analysis of vaginal leukocytosis, lactobacillary grades, and the presence of positive vaginal culture results showed that interleukin 1beta concentration was most closely related to the lactobacillary grade, leukemia inhibitory factor concentration was most closely related to the lactobacillary grade and positive culture results, interleukin 8 concentration was most closely related to positive culture results, and interleukin 1 receptor antagonist concentration was most closely related to vaginal leukocytosis and positive culture results. The concentration ratio of interleukin 1beta to interleukin 1 receptor antagonist remained stable, except when vaginal leukocytosis increased. In its most severe form, with >10 leukocytes per epithelial cell present, a decompensation of the vaginal flora with a collapse in interleukin 1beta and interleukin 1 receptor antagonist concentrations was seen, but there was a concurrent sharp increase in leukemia inhibitory factor concentration. This pattern was completely different from the course of the cytokine concentrations associated with a lactobacillary grade increase. CONCLUSION: Both disturbed lactobacillary grade and the presence of increasing vaginal leukocytosis were correlated with lactobacillary substrate (lactate) concentration, pH, and the concentrations of a variety of cytokines. There was a remarkably linear increase in these cytokines as either leukocytosis or lactobacillary grade became more severe. In circumstances in which leukocytosis was extreme, however, interleukin 1beta was no longer produced but leukemia inhibitory factor concentrations increased. We speculate that in extreme inflammation the body tries to limit the damage that can be done by exaggerated cytokine production.