Coming in early 2018 is a new one-dose oral treatment for bacterial vaginosis (BV). The drug’s effectiveness is similar to that of the metronidazole, a treatment currently recommended by the Centers for Disease Control and Prevention, but with an ease of use that may enhance adherence to treatment regimen.
According to the 2015 STD Treatment Guidelines issued by the Centers for Disease Control and Prevention, three regimens are currently recommended:
1) Metronidazole, 500 mg orally twice daily for 7 days OR
2) Metronidazole gel, 0.75%, one full applicator (5 g) vaginally at bed time for 5 days OR
3) Clindamycin cream, 2%, one full applicator (5 g) vaginally at bedtime for 7 days.
Other alternatives are oral clindamycin 300 mg two times a day for 7 days; clindamycin ovules 100 mg vaginally at bedtime for 3 days; tinidazole two grams orally once daily for 3 days; or tinidazole one gram orally once daily for 5 days. In pregnancy, oral regimens are generally preferred.
Unfortunately, adherence to treatment is a barrier to effective cure, and recurrent BV infection within a year of treatment is more than 50%.[i] An effective treatment regimen that enhances adherence would be welcome, and many hope that the new one-dose secnidazole can be helpful in that regard. This new formulation of the 5-nitroimidazole antimicrobial agent will be available in 2g oral granules. The granules, provided as a single-dose therapy for oral use, would be sprinkled onto applesauce, yogurt or pudding and consumed once within 30 minutes without chewing or crunching the granules. The granules are not intended to be dissolved in liquid.[ii] The most common adverse events occurring in (≥2%) of patients receiving SOLOSEC 2g oral granules during clinical studies were vulvovaginal candidiasis (9.6%), headache (3.6%), nausea (3.6%), dysgeusia (3.4%), vomiting (2.5%), diarrhea (2.5%), abdominal pain (2.0%), and vulvovaginal pruritus (2.0%). Any potential risk of carcinogenicity is unclear. Chronic use should be avoided.
About 30% of reproductive-age women in the United States are affected by BV, or about 4 million each year.[iii] BV is the most common cause of vaginal discharge or malodor (a fishy odor) among women seeing their clinicians, though many or most women with BV are asymptomatic.
Although the cause of BV remains a mystery, it appears that a disruption in the delicate balance of vaginal microflora is at the root of the infection. BV is essentially polymicrobial. Hydrogen-peroxide-producing Lactobacilli predominate in the healthy vagina, but in the presence of BV, other bacteria (Gardnerella vaginalis, Prevotella, Porphyromonas, peptostreptococci, Mobiluncus, and others)[iv] replace the normal Lactobaccilli. Activities that may disrupt the vaginal microflora and serve as risk factors for BV, including douching, new or multiple sex partners, antibiotic use, and using an IUD. BV is not usually considered a specific STI; however, it probably results at least initially from transfer of the associated bacteria from a sex partner who harbors them. For example, BV occurs frequently in women who regularly have sex with women, and BV-associated bacteria have been consistently detected on the scrotum and penis, especially underneath the foreskin.
BV is not simply the annoying vaginitis once thought to be benign. It is associated with an increased risk of PID and may also cause cervicitis as well as increase the woman’s risk of acquiring chlamydia, gonorrhea, trichomoniasis, and HIV. Infected women can have an increased risk of adverse pregnancy outcomes, including preterm delivery and low birth weight. The presence of bacterial vaginosis is associated with a 40% increased risk of preterm delivery of a low-birth-weight infant. [v] The highest risk was among those with women with both vaginal bacteroides and Mycoplasma hominis (odds ratio, 2.1).
The most common clinical manifestation of BV is excessive or malodorous discharge that coats the walls of the vagina. Although mild itching can sometimes occur, the infection usually causes no significant irritation, pain, or erytheyma. If the discharge is profuse, the woman can experience edema, erythema, and pruritus of the external genitalia.
The clinical diagnosis of BV is made if three of the following four (Amsel) criteria are present:
1) Increased amounts of homogenous discharge
2) Elevated vaginal pH (greater than 4.5)
3) Fishy odor on addition of 10% KOH
4) Identification of clue cells (small coccobacillary organisms associated with epithelial cells) on saline wet mount (> 20% of vaginal epithelial cells)
Alternatively, rapid tests that detect high numbers of Gardnerella vaginalis bacteria, or byproducts of anaerobic metabolism such as sialidase, are also available. Cultures and nucleic acid amplification assays (NAAT) such as PCR for individual bacteria are not useful and should not be performed.[vi] NAATs that provide a result based on measuring the combination of bacteria present in vaginal fluid appear promising. Gram stain is primarily used in research.
Recurrence rates can be common. Risks factors include sexual activity with the same partner and inconsistent condom use. Should sex partners be treated, too? Although past studies did not find that treatment of the male partner was effective in enhancing cure of BV,[vii] this approach is currently under study. Some specialists recommend that before performing surgical abortion, providers screen and treat BV in addition to providing routine antibiotic prophylaxis, but there are no data to support this practice.
[i] Bradshaw CS, Morton AN, Hocking J, et al. High recurrence rates of bacterial vaginosis over the course of 12 months after oral metronidazole therapy and factors associated with recurrence. J Infect Dis 2006;1;193:1478-86.
[ii] Solosec. Indication and important safety information. At http://www.solosec.com/pdf/symbiomix-full-prescribing-information.pdf. Accessed 12-1-17.
[iii] Koumans EH, Sternberg M, Bruce C, et al. The prevalence of bacterial vaginosis in the United States, 2001-2004; associations with symptoms, sexual behaviors, and reproductive health. Sex Transm Dis 2007;34:864-9.
[v] Hillier SL, Nugent RP, Eschenbach, DA, et al. Association between bacterial vaginosis and preterm delivery of a low-birth-weight-infant. N Engl J Med 1995;333:1737-1742. https://doi.org/10.1056%2FNEJM199512283332604
[vi] Marrazzo J, Park I. Reproductive tract infections, including HIV and other sexually transmitted infections. In: Hatcher RA, et al. (Eds.) Contraceptive technology, 21st edition. In preparation.
[vii] Amaya-Guio J, Viveros-Carreño DA, Sierra-Barrios EM, Martinez-Velasquez MY, Grillo-Ardila CF. antibiotic treatment for the sexual partners of women with bacterial vaginosis. Cochrane Database Syst Rev 2016;10. doi:10.1002/14651858.CD011701.pub