Activated charcoal as an effective treatment for bacterial vaginosis

Abstract

Purpose

Bacterial vaginosis is one of the most common infectious disorders that affect women of reproductive age. For many years, antibiotics have been used for the treatment of this infection. However, antibiotics may adversely affect the normal vaginal bacterial flora. Therefore, development of treatments without adverse effects is urgently required. The aim of this study was to evaluate the efficacy of activated charcoal in the treatment of bacterial vaginosis, and to estimate the changes of lactobacilli in the vagina.

Methods

1) An unblinded prospective randomized controlled 10-day trial was designed. This study included 64 women, aged 18–37 (mean age, 28 years) with newly diagnosed bacterial vaginosis. Bacterial vaginosis was diagnosed using the Amsel criteria. The subjects with complete lack of vaginal lactobacilli at baseline (6/70) were excluded from the study. Patients with bacterial vaginosis were divided in two groups, one group was treated with trans-vaginal tampons containing a 10% solution of activated charcoal, the other one as a control received a chloramphenicol (100 mg) vaginal suppository.

Results

1) In the group treated with chloramphenicol, lactobacilli were completely lost in 84.3% of the subjects (27/32), whereas only 3.1% (1/32) of the subjects treated with activated charcoal showed this loss; the difference was statistically significant (Fisher's exact test). 2) Both treatments successfully reduced the amount of vaginal secretion. 3) Both treatments showed significant improvements in the magnitude of malodor.

Conclusions

In the present study, a novel treatment with activated charcoal tampons showed remarkable improvements of the symptoms of bacterial vaginosis. This approach is a potentially promising treatment for this infection without adverse effects.

Introduction

Bacterial vaginosis is one of the most common infectious disorders that affect women of reproductive age [1]. However, there are few epidemiologic studies of this infection. Shimano et al. examined 6083 pregnant women, and reported that the prevalence of bacterial vaginosis increased from 13.6% in 1993 to 21.4% in 2000 in Northern Japan [2].

In recent years, there has been growing public concern regarding bacterial vaginosis, because of its association with numerous health problems, including preterm birth [3], [4], pelvic inflammatory disease [5], [6], and susceptibility to HIV infection [7].

Although the causes of bacterial vaginosis are yet to be fully explored, it is known that women who have never been sexually active are rarely affected. On the other hand, the infection is associated with having multiple sex partners and douching; however, it is unclear whether it is a sexually transmitted disease.

The human vagina is a dynamic and complex microbial ecosystem in which the dominance of Lactobacillus species plays an important protective role in maintaining its health. It is widely accepted that microbial alteration in the vaginal flora is a major cause of bacterial vaginosis. A number of studies also reported that lack of vaginal lactobacilli is an important risk factor of bacterial vaginosis.

Clinically, bacterial vaginosis is a syndrome resulting from replacement of Lactobacillus species in the vaginal flora with high concentrations of anaerobic bacteria (e.g., Gardnerella vaginalis, Bacteroides sp., Prevotella sp., Mobiluncus sp., and Mycoplasma hominis). Among the Lactobacillus species, H₂O₂-producing Lactobacillus sp. play an important role in maintaining the normal vaginal bacterial flora because hydrogen peroxide (H₂O₂) can be toxic to organisms (e.g., G. vaginalis, Bacteroides sp.) that produce little or no H₂O₂-scavenging enzymes (e.g., catalase). Their absence could allow an overgrowth of catalase-negative organisms, such as those found in women with bacterial vaginosis [8]. Eschenbach et al. showed that H₂O₂-producing Lactobacillus sp. were found in 27 out of 28 normal women (96%) and 4 out of 67 women with bacterial vaginosis (6%), suggesting that the production of H₂O₂ may represent a nonspecific antimicrobial defense mechanism of the normal vaginal ecosystem [9]. Recent studies have also suggested that certain strains of H₂O₂-producing vaginal lactobacilli are able to inhibit the adherence of G. vaginalis to the vaginal epithelium and/or produce H₂O₂, lactic acid and/or bacteriocins, which inhibit the growth of bacteria causing vaginosis [10]. In summary, there seems to be an association between the absence or low concentrations of vaginal lactobacilli and the development of bacterial vaginosis.

The most common symptom of bacterial vaginosis is an excessive white-gray vaginal discharge with an unpleasant odor (especially after sexual intercourse). This malodorous discharge coats the walls of the vagina, but does not cause irritation. However, up to 50% of women with bacterial vaginosis may not be diagnosed as having the infection.

For the treatment of bacterial vaginosis, several antibiotics have been introduced such as metronidazole or clindamycin, given either orally or vaginally. In Japan, the treatment is based on the use of chloramphenicol given trans-vaginally. However, antibiotic treatment may affect the normal vaginal bacterial flora. Metronidazole and clindamycin are effective, but negatively affect the growth of Lactobacillus and therefore causes a higher risk of recurrences [11]. Introduction of treatments without antibiotics are urgently required.

For centuries natural charcoal has been used for the treatment of ailments and injuries [12]. Activated charcoal has also a role in the management of overdosed patients and is useful for the removal of bacteria and bacterial toxins [13], [14], [15], [16]. Routinely administered to reduce the gastrointestinal (GI) absorption of many drugs, repeated doses of charcoal have been shown to enhance drug elimination [17].

Nakata et al. analyzed the adsorption properties of activated charcoal on verotoxin-producing Escherichia coli, and showed that the adsorption was dose dependent. They also found that activated charcoal had lower binding capacity to Lactobacillus acidophilus [18].

Activated charcoal is a form of carbon produced from nutshells and wood chips, that has been processed to make it extremely porous and have a large surface area for adsorption. Due to its high degree of microporosity, just 1 g of activated charcoal has a surface area of approximately 500 m². The structure of activated charcoal is constituted by various types of micropores and it can bind and absorb substances larger than the carbon particles.

We hypothesized that activated charcoal is an effective means for maintaining a predominance of Lactobacillus sp. in the vaginal flora and preserving a healthy microbial ecosystem.