Changes in Vaginal Bacterial Concentrations with Intravaginal Metronidazole Therapy for Bacterial Vaginosis as Assessed by Quantitative PCR

Abstract

Several fastidious bacteria have been associated with bacterial vaginosis (BV) using broad-range bacterial PCR methods such as consensus sequence 16S rRNA gene PCR, but their role in BV remains poorly defined. We describe changes in vaginal bacterial concentrations following metronidazole therapy for BV. Vaginal swabs were collected from women with BV diagnosed using Amsel clinical criteria, and vaginal fluid was assessed by Gram stain to generate Nugent scores. Follow-up swabs were collected 1 month after a 5-day course of vaginal 0.75% metronidazole gel and analyzed for 24 subjects with cured BV and 24 subjects with persistent BV. Changes in bacterial concentrations were measured using eight bacterium-specific 16S rRNA gene quantitative PCR assays. DNA from several fastidious BV-associated bacteria (BVAB) were present at high concentrations in the vagina prior to treatment. Successful antibiotic therapy resulted in 3-to 4-log reductions in median bacterial loads of BVAB1 (P ‫؍‬ 0.02), BVAB2 (P ‫؍‬ 0.0004), BVAB3 (P ‫؍‬ 0.03), a Megasphaera-like bacterium (P < 0.0001), Atopobium species (P < 0.0001), Leptotrichia/Sneathia species (P ‫؍‬ 0.0002), and Gardnerella vaginalis (P < 0.0001). Median posttreatment bacterial levels did not change significantly in subjects with persistent BV except for a decline in levels of BVAB3. The presence or absence of BV is reflected by vaginal concentrations of BV-associated bacteria such as BVAB1, BVAB2, Leptotrichia/Sneathia species, Atopobium species, Gardnerella vaginalis, and a Megasphaera-like bacterium, suggesting that these bacteria play an important role in BV pathogenesis and may be suitable markers of disease and treatment response.Bacterial vaginosis (BV) is a very common condition, affecting 10 to 37% of women (24), with particularly high prevalences reported in areas of sub-Saharan Africa (3, 25) and among African-American women (51%) (15). BV is the most common cause of vaginitis and vaginal discharge and has been linked to several adverse health outcomes including preterm labor, pelvic inflammatory disease, and human immunodeficiency virus acquisition (12,18,19).Women with BV experience a loss of vaginal Lactobacillus species that produce hydrogen peroxide (primarily Lactobacillus crispatus) and the acquisition of several facultative or anaerobic bacteria, but no single cultivated bacterium has been conclusively demonstrated to cause BV. The profound shifts in vaginal microbiota that characterize BV and the clinical response to antibiotics such as metronidazole or clindamycin suggest that anaerobic bacteria play a key role. The recent use of cultivation-independent methods (e.g., broad-range 16S rRNA gene PCR) to characterize the vaginal microbiota (5, 26) has identified novel fastidious bacteria that appear to be highly associated with BV, including three bacteria of the order Clostridiales that are not closely related to any previously identified bacteria and that we have designated BV-associated bacterium 1 (BVAB1), BVAB2, and BVAB3 (6). Other fastidious bacteri...

Bacterial Vaginosis–Associated Bacteria in Men

“…were detected in the anus, 27 highlighting their potential role in incident BV. Treatment of women with BV with metronidazole was followed by significant reductions in bacterial concentrations of these bacteria, 28 and the type strain was sensitive to vancomycin but resistant to tetracycline (>50 μg/mL) and ciprofloxacin (>25 μg/mL). 25 This latter observation is in sharp contrast to the high clinical efficacy of doxycycline that we observed among these men with NGU and may be caused by differences in antimicrobial susceptibility of individual strains.…”

Vaginal microbiota and genitourinary menopausal symptoms: a cross-sectional analysis

“…For quantification of L. crispatus and L. iners , species-specific qPCR using a TaqMan-based assay was performed as previously described. 18,20 …”

Prevalence of Mycoplasma hominis and Ureaplasma spp. in Routine Gynecological Care in Sao Paulo City, Brazil

“…Moreover, both microorganisms are usually associated with young age, lower socioeconomic status, sexual activity with multiple partners, black ethnic groups, smoking, vaginal douching and oral contraceptive use (20)(21)(22). However, differences in prevalence according to race and socioeconomic status are reported (22)(23)(24), and differences by gender are also suggested (24).…”