Vaginitis in Nonpregnant Patients: ACOG Practice Bulletin Number 215

Sexually transmitted infections and the vaginal microbiome after vaginoplasty

PURPOSE OF THE REVIEW

Transgender and gender-diverse individuals (TGD) are at risk for sexually transmitted infections. Gender affirmation surgery is a cornerstone of care for many TGD individuals. For genital gender affirmation, the surgical creation of a vagina may be performed through a number of techniques. Those who have undergone vaginoplasty have unique anatomical and biopsychosocial considerations, which we discuss.

RECENT FINDINGS

While sexually-transmitted infections including HPV, HSV, HIV, gonorrhea, and chlamydia, have been described in TGD individuals after vaginoplasty, the reports are very rare, and the provider should maintain an index of suspicion and maintain a broad differential for symptoms including neovaginal discharge. We discuss the association of the neovaginal microbiota composition with bacterial vaginosis, and how its modulation could potentially reduce bacterial vaginosis and sexually transmitted infection risk.

SUMMARY

We examine the literature regarding sexually-transmitted infections following vaginoplasty, and the neovaginal microbiome and its similarities and differences relative to the natal vaginal microbiome.

Recurrent Infectious Vaginitis: A Practical Approach for the Primary Care Clinician

Recurrent infectious vaginitis can lead to significant morbidity, patient frustration, and health care costs. The most common causes are bacterial vaginosis (BV) and vulvovaginal candidiasis (VVC); however, other infectious and noninfectious etiologies should be considered in patients with recurrent symptoms. A detailed history and physical examination with appropriate testing at the time of symptoms is critical to establishing a correct diagnosis. Management options for recurrent BV and VVC are limited. Complex cases including those with atypical symptoms, negative testing for common causes, refractory symptoms despite appropriate therapy or recurrences during suppressive therapy will require referral to specialist care.

A microfluidic-chip-based system with loop-mediated isothermal amplification for rapid and parallel detection of Trichomonas vaginalis and human papillomavirus

Cervical cancer is a significant global health issue primarily caused by high-risk types of human papillomavirus (HPV). Recent studies have reported an association between Trichomonas vaginalis (T. vaginalis) infections and HPV infections, highlighting the importance of simultaneously detecting these pathogens for effective cervical cancer risk management. However, current methods for detecting both T. vaginalis and HPV are limited. In this study, we present a novel approach using a microfluidic-chip-based system with loop-mediated isothermal amplification (LAMP) for the rapid and parallel detection of T. vaginalis, HPV16, HPV18, and HPV52 in a reagent-efficient and user-friendly manner. Compared to conventional LAMP assays in tubes, our system exhibits enhanced sensitivity with values of 2.43 × 101, 3.00 × 102, 3.57 × 101, and 3.60 × 102 copies per reaction for T. vaginalis, HPV16, HPV18, and HPV52, respectively. Additionally, we validated the performance of our chip by testing 47 clinical samples, yielding results consistent with the diagnostic methods used by the hospital. Therefore, our system not only offers a promising solution for concurrent diagnosis of T. vaginalis and HPV infections, particularly in resource-limited areas, due to its cost-effectiveness, ease of use, and rapid and accurate detection performance, but can also contribute to future research on the co-infection of these two pathogens. Moreover, the system possesses the capability to simultaneously detect up to 22 different types of pathogens, making it applicable across a wide range of domains such as diagnostics, food safety, and water monitoring.

Mycobiome Study Reveals Different Pathogens of Vulvovaginal Candidiasis Shape Characteristic Vaginal Bacteriome

Vulvovaginal candidiasis (VVC) can alter the vaginal microbiome composition and structure, and this may be correlated with its variable treatment efficacy. Integrated analysis of the mycobiome and bacteriome in VVC could facilitate accurate diagnosis of infected patients and further decipher the characterized bacteriome in different types of VVC. Our mycobiome analysis determined two common types of VVC, which were clustered into two community state types (CSTs) featured by Candida glabrata (CST I) and Candida albicans (CST II). Subsequently, we compared the vaginal bacteriome in two CSTs of VVC and two other types of reproductive tract infections (RTIs), bacterial vaginosis (BV) and Ureaplasma urealyticum (UU) infection. The vaginal bacteriome in VVC patients was between the healthy and other RTIs (BV and UU) status, it bore the greatest resemblance to that of healthy subjects. While BV and UU patients have the unique vaginal microbiota community structure, which very different with healthy women. Compared with CST II, the vaginal bacteriome of CST I VVC was characterized by Prevotella, a key signature in BV. In comparison, CST II was featured by Ureaplasma, the pathogen of UU. The findings of our study highlight the need for co-analysis and simultaneous consideration of vaginal mycobiome and bacteriome in the diagnosis and treatment of VVC to solve common clinical problems, such as unsatisfactory cure rates and recurrent symptoms. IMPORTANCE Fungi headed by C. albicans play a critical role in VVC but are not sufficient for its occurrence, indicating the involvement of other factors, such as the vaginal bacteriome. We found that different CST correspond to different bacterial composition in patients with VVC, and this could underlie the alteration of vaginal microorganism environment in VVC patients. We believe that this correlation should not be ignored, and it may be related to the unsatisfactory treatment outcomes and high recurrence rate of VVC. Here, we provided evidence for associations between vaginal bacteriome patterns and fungal infection. Screening specific biomarkers for three common RTIs paves a theoretical basis for further development of personalized precision treatment.

Anti-Candida and Anti-Inflammatory Properties of a Vaginal Gel Formulation: Novel Data Concerning Vaginal Infection and Dysbiosis

Vaginal ecosystem is a unique environment where, in physiological conditions, lactobacilli dominate. However, pathogenic microbial species responsible for vaginitis and vaginosis can also harbor vaginal microbiota. To extend our previously published data, we analyzed here both the anti-Candida and anti-inflammatory properties of the vaginal gel formulation, Respecta^® Balance Gel (RBG), commercialized as an adjuvant to treat vaginitis and vaginosis. We evaluated its activity by an in vitro model where a monolayer of A-431 vaginal epithelial cells was infected by Candida albicans in the presence of RBG or the placebo formulation (pRBG). Specifically, we tested the RBG capacity to counteract C. albicans virulence factors and their anti-inflammatory properties. Our results show that, unlike the placebo, RBG reduces C. albicans adhesion, its capacity to form hyphae and C. albicans-induced vaginal cell damage. Interestingly, both RBG and pRBG reduce LPS-induced IL-8 secretion (with RBG being the most effective), demonstrating that also the placebo retains anti-inflammatory properties. From our experimental approach, we highlighted the possible role of farnesol on such effects, but we would like to point out that lactic acid, polydextrose and glycogen too must be relevant in the actual application. In summary, our results show that RBG impairs C. albicans virulence and is able to reduce the inflammation in the vaginal environment, ultimately allowing the establishment of a balanced vaginal ecosystem.

Release Kinetics of Metronidazole from 3D Printed Silicone Scaffolds for Sustained Application to the Female Reproductive Tract

Sustained vaginal administration of antibiotics or probiotics has been proposed to improve treatment efficacy for bacterial vaginosis. 3D printing has shown promise for development of systems for local agent delivery. In contrast to oral ingestion, agent release kinetics can be fine-tuned by the 3D printing of specialized scaffold designs tailored for particular treatments while enhancing dosage effectiveness via localized sustained release. It has been challenging to establish scaffold properties as a function of fabrication parameters to obtain sustained release. In particular, the relationships between scaffold curing conditions, compressive strength, and drug release kinetics remain poorly understood. This study evaluates 3D printed scaffold formulation and feasibility to sustain the release of metronidazole, a commonly used antibiotic for BV. Cylindrical silicone scaffolds were printed and cured using three different conditions relevant to potential future incorporation of temperature-sensitive labile biologics. Compressive strength and drug release were monitored for 14d in simulated vaginal fluid to assess long-term effects of fabrication conditions on mechanical integrity and release kinetics. Scaffolds were mechanically evaluated to determine compressive and tensile strength, and elastic modulus. Release profiles were fitted to previous kinetic models to differentiate potential release mechanisms. The Higuchi, Korsmeyer-Peppas, and Peppas-Sahlin models best described the release, indicating similarity to release from insoluble or polymeric matrices. This study shows the feasibility of 3D printed silicone scaffolds to provide sustained metronidazole release over 14d, with compressive strength and drug release kinetics tuned by the fabrication parameters.

Clinical Evaluation of a New Molecular Test for the Detection of Organisms Causing Vaginitis and Vaginosis

In this prospective, observational, method comparison clinical study, the Xpert Xpress MVP test (MVP) was evaluated using both clinician-collected (CVS) and self-collected vaginal swabs (SVS) collected in a clinical setting. The study was conducted at 12 sites, including point-of-care (POC) settings, from geographically diverse locations in the United States. Participants were biologically female patients ≥ 14 years old with signs and/or symptoms of vaginitis/vaginosis. MVP test results for BV were compared to the BD MAX Vaginal Panel (BDVP). Results for Candida group and Candida glabrata and Candida krusei targets (species not differentiated) were assessed relative to yeast culture followed by mass spectrometry for species identification. Trichomonas vaginalis (TV) results were compared relative to a composite method that included results from the BDVP and InPouch TV culture. The investigational test demonstrated high positive percent agreement ranging from 93.6 to 99.0%, and negative percent agreement ranging from 92.1% to 99.8% for both CVS and SVS specimens, indicating it may be a valuable tool for the diagnosis of vaginitis/vaginosis in laboratory and POC settings.

Oral Ibrexafungerp for Vulvovaginal Candidiasis Treatment: An Analysis of VANISH 303 and VANISH 306

Background: Ibrexafungerp is a novel antifungal treatment for acute vulvovaginal candidiasis (VVC). Using pooled data from two phase three studies (VANISH 303 and 306) in the treatment of acute VVC, this analysis sought to determine the effectiveness of ibrexafungerp in various patient subgroups that may impact outcomes. Materials and Methods: Data from VANISH 303 (NCT03734991) and VANISH 306 (NCT03987620) evaluating ibrexafungerp 300 mg twice daily (BID) for 1 day versus placebo, were pooled and analyzed to determine clinical cure rate, clinical improvement, and mycological cure at the test-of-cure visit (day 11 ± 3) and symptom resolution at the follow-up visit (day 25 ± 4) in the overall population. Patient subgroups analyzed included race, body mass index (BMI), baseline vulvovaginal signs and symptoms (VSS) score, and Candida species. Results: At the test-of-cure visit, patients receiving ibrexafungerp, compared with those who received placebo, had significantly higher rates of clinical cure (56.9% [214/376 patients] vs. 35.7% [65/182 patients]), clinical improvement (68.4% [257/376 patients] vs. 45.1% [82/182 patients]), and mycological cure (54.0% [203/376 patients] vs. 24.2% [44/182 patients]; all p < 0.0001). At the follow-up visit, patients receiving ibrexafungerp had sustained responses with higher symptom resolution rates (66.8% [251/376 patients]) versus placebo (48.4% [88/182 patients]; p < 0.0001). Race, BMI, baseline VSS score (including VSS severity score 13-18), and Candida species infection did not adversely affect clinical cure rates. Safety analysis results were consistent with the individual studies. Conclusions: Ibrexafungerp provides a safe and well-tolerated first-in-class fungicidal, 1-day oral treatment for patients with acute VVC, the first new therapy in >20 years. Clinical Trial Registration Number: NCT03734991.

The role of the genital microbiota in the acquisition and pathogenesis of sexually transmitted infections

PURPOSE OF REVIEW

There are an estimated 374 million new sexually transmitted infections (STIs) worldwide every year. Our review article examines the current evidence of how STI acquisition, transmission, and pathogenesis is impacted upon by the genital microbiota, with a focus on epidemiological, biochemical, and immunological features.

RECENT FINDINGS

At least in women, a genital microbiota dominated by lactobacilli has long been considered optimal for reproductive health, while depletion of lactobacilli may lead to a genital microenvironment dominated by anaerobic pathogens, which can manifest clinically as bacterial vaginosis. Recent research efforts have characterized genital microbiota composition in greater resolution, sometimes at species-level, using proteomics, metabolomics, and deep sequencing. This has enhanced our understanding of how specific microbiota members influence acquisition or clinical manifestation of STI pathogen infection. Other advances include a steady, though still slow, increase in the number of studies that sought to determine the genital (penile or urethral) microbiota of males and how it may impact that of their female partners' genital microbiota and risk of STI acquisition. Altogether, these data enabled us to explore the concept that genital microbiota may be sexually transmitted and influence pathogenesis and clinical presentation of other STI.

SUMMARY

With STI infection rates increasing worldwide, it is important now more than ever to find novel STI prevention strategies. Understanding if and how the genital microbiota is a modifiable risk factor for STI transmission, acquisition, and clinical manifestation may prove to be an important strategy in our efforts to curb morbidity in at risk populations.

Epidemiological analysis of hydrometra and its predictive value in gynecological tumors

Introduction

Hydrometra is a common gynecological disease, especially in postmenopausal women. However, its epidemiology, harmfulness, and value in predicting gynecological tumors have not been clearly elucidated.

Methods

In this study, the prevalence rate of and risk factors for hydrometra were investigated in 3,903 women who underwent screening for gynecological diseases at Zhoupu Hospital in Shanghai from 1 January to 31 December 2021. In addition, pathological distribution of hydrometra and its predictive value in gynecological tumors were studied in another 186 patients in whom hydrometra was diagnosed sonographically at Zhoupu Hospital, from 1 January 2020 to 31 December 2021, and who underwent hysteroscopy and postoperative pathological examination.

Results

The observed prevalence rate of hydrometra was 10.86%, which was higher than the prevalence of other gynecological diseases. Univariate and multivariate analysis indicated that advanced age (OR 1.11) and vaginitis (OR 3.18) were independent risk factors for hydrometra. Among 186 patients with a sonographic diagnosis of uterine fluid, simple hydrometra accounted for 34.41% of cases, inflammation accounted for 16.23%, and hematometra accounted for 2.15%, while gynecological tumors accounted for 5.91%. Moreover, univariate and multivariate analysis indicated that a higher body mass index (>23.92 kg/m²), greater hydrometra volume (i.e., distance between the two layers of endometrium>4.75 mm), and abnormal vaginal bleeding were high-risk predictive factors for gynecological tumors.

Discussion

In conclusion, hydrometra is a common disease, and is a risk factor for endometrial cancer and cervical cancer, especially in patients with higher hydrometra volume, higher BMI, and abnormal vaginal bleeding. It is necessary to pay more attention to hydrometra.

Study of Prescription-Indication of Outpatient Systemic Anti-Fungals in a Colombian Population. A Cross-Sectional Study

The inappropriate use of antifungals is associated with greater antimicrobial resistance, costs, adverse events, and worse clinical outcomes. The aim of this study was to determine prescription patterns and approved and unapproved indications for systemic antifungals in a group of patients in Colombia. This was a cross-sectional study on indications for the use of systemic antifungals in outpatients from a drug dispensing database of approximately 9.2 million people affiliated with the Colombian Health System. Sociodemographic, pharmacological, and clinical variables were considered. Descriptive, bivariate, and multivariate analyses were performed. A total of 74,603 patients with antifungal prescriptions were identified; they had a median age of 36.0 years (interquartile range: 22.0−53.0 years), and 67.3% of patients were women. Fluconazole (66.5%) was the most prescribed antifungal for indications such as vaginitis, vulvitis, and vulvovaginitis (35.0%). A total of 29.3% of the prescriptions were used in unapproved indications. A total of 96.3% of ketoconazole users used the medication in unapproved indications. Men (OR: 1.91; CI95%: 1.79−2.04), <18 years of age (OR: 1.20; CI95%: 1.11−1.31), from the Caribbean region (OR: 1.26; CI95%: 1.18−1.34), with chronic obstructive pulmonary disease (OR: 1.80; CI95%: 1.27−2.54), prescriptions made by a general practitioner (OR: 1.17; CI95%: 1.04−1.31), receiving comedications (OR: 1.58; CI95%: 1.48−1.69), and the concomitant use of other antimicrobials (OR: 1.77; CI95%: 1.66−1.88) were associated with a higher probability that the antifungal was used for unapproved indications; deep mycosis (OR: 0.49; CI95%: 0.41−0.58), prescribing fluconazole (OR: 0.06; CI95%: 0.06−0.06), and having diabetes mellitus (OR: 0.33; CI95%: 0.29−0.37), cancer (OR: 0.13; CI95%: 0.11−0.16), or HIV (OR: 0.07; CI95%: 0.04−0.09) reduced this risk. Systemic antifungals were mostly used for the management of superficial mycoses, especially at the gynecological level. In addition, more than a quarter of patients received these medications in unapproved indications, and there was broad inappropriate use of ketoconazole.

Systematic Review: The Neovaginal Microbiome

OBJECTIVE

To review neovaginal colonization and inflammatory patterns, and factors that may impact this.

METHODS

A systematic review of the neovaginal microbiome was conducted in concordance with PRISMA guidelines through October 2021.

RESULTS

Thirteen articles were included, totaling 458 patients. Neovaginal constructions were most commonly performed with penile and scrotal skin grafts, sigmoid segments, and peritoneal grafts. The neovaginal microflora identified were generally polymicrobial and shared similarities with the native tissue. Nine studies identified Lactobacillus: 5/6 for penile skin, 1/3 for sigmoid, 1/1 for peritoneum, and 2/3 for other graft types, suggesting that the neovagina may support Lactobacillus either innately, via rectal migration or oral probiotic supplementation. A polymicrobial, bacterial vaginosis-like environment was found in nine studies. Inflammatory markers were also described: 2/6 for penile skin, 2/3 for sigmoid, 0/1 for peritoneum, and 1/3 for other graft types. Scant data were available on the impact of postsurgical duration, oral hormones, dilating, sexual practices, or douching on the neovaginal microbiome.

CONCLUSION

Understanding and optimizing the polymicrobial neovaginal microenvironment may improve surgical outcomes, specifically inflammatory, pain, and infectious. Future research should focus on standardizing testing and classification systems, and treating neovaginal dysbiosis.

Efficacy and safety of oral ibrexafungerp for the treatment of acute vulvovaginal candidiasis: a global phase 3, randomised, placebo-controlled superiority study (VANISH 306)

Objective

To evaluate the efficacy and safety of ibrexafungerp versus placebo for acute vulvovaginal candidiasis (VVC) treatment.

Design

Global phase 3, randomised, placebo‐controlled superiority study.

Setting

Study sites in the USA (n = 19) and Bulgaria (n = 18).

Population

Female patients aged ≥12 years with acute VVC and a vulvovaginal signs and symptoms (VSS) score ≥4 at baseline.

Methods

Patients were randomly assigned 2:1 to ibrexafungerp (300 mg twice for 1 day) or placebo.

Main outcome measures

The primary endpoint was the percentage of patients with a clinical cure (VSS = 0) at the test‐of‐cure visit (day 11 ± 3). Secondary endpoints included percentages of patients with mycological eradication, clinical cure and mycological eradication (overall success), clinical improvement (VSS ≤1) at test‐of‐cure visit, and complete resolution of symptoms at follow‐up visit (day 25 ± 4).

Results

At the test‐of‐cure visit, patients receiving ibrexafungerp had significantly higher rates of clinical cure (63.3% [119/188] versus 44.0% [37/84]; P = 0.007), mycological eradication (58.5% [110/188] versus 29.8% [25/84]; P < 0.001), overall success (46.1% [82/188] versus 28.4% [23/84]; P = 0.022) and clinical improvement (72.3% [136/188] versus 54.8% [46/84]; P = 0.01) versus those receiving placebo. Symptom resolution was sustained and further increased with ibrexafungerp (73.9%) versus placebo (52.4%) at follow‐up (P = 0.001). Ibrexafungerp was generally well tolerated. Adverse events were primarily gastrointestinal and were mild to moderate in severity.

Conclusions

Ibrexafungerp demonstrated statistical superiority over placebo for the primary and secondary endpoints. Ibrexafungerp is a promising novel, well‐tolerated and effective oral 1‐day treatment for acute VVC.

Tweetable abstract

Ibrexafungerp is statistically superior to placebo for the treatment of vulvovaginal candidiasis.

Ibrexafungerp is statistically superior to placebo for the treatment of vulvovaginal candidiasis.

Linked article This article is commented on by KSJ Olah, p. 421–422 in this issue. To view this mini commentary visit https://doi.org/10.1111/1471-0528.17000.

Ibrexafungerp versus placebo for vulvovaginal candidiasis treatment: a phase 3, randomized, controlled superiority trial (VANISH 303)

Background

Current treatment of vulvovaginal candidiasis (VVC) is largely limited to azole therapy. Ibrexafungerp is a first-in-class triterpenoid antifungal with broad-spectrum anti-Candida fungicidal activity. The objective of this study was to evaluate the efficacy and safety of ibrexafungerp compared with placebo in patients with acute VVC.

Methods

Patients were randomly assigned 2:1 to receive ibrexafungerp (300 mg twice for 1 day) or placebo. The primary endpoint was the percentage of patients with a clinical cure (complete resolution of vulvovaginal signs and symptoms [VSS] = 0) at test-of-cure (day 11 ± 3). Secondary endpoints included the percentage of patients with mycological eradication, overall success (clinical cure and mycological eradication), clinical improvement (VSS ≤ 1) at test-of-cure, and symptom resolution at follow-up (day 25 ± 4).

Results

Patients receiving ibrexafungerp had significantly higher rates of clinical cure (50.5% [95/188] vs 28.6% [28/98]; P = .001), mycological eradication (49.5% [93/188] vs 19.4% [19/98]; P < .001), and overall success (36.0% [64/178] vs 12.6% [12/95]; P < .001) compared with placebo. Symptom resolution was sustained and further increased with ibrexafungerp compared with placebo (59.6% [112/188] vs 44.9% [44/98]; P = .009) at follow-up. Post hoc analysis showed similar rates of clinical cure and clinical improvement at test-of-cure for Black patients (54.8% [40/73] and 63.4% [47/73], respectively) and patients with a body mass index >35 (54.5% [24/44] and 68.2% [30/44], respectively) compared with overall rates. Ibrexafungerp was well tolerated. Adverse events were primarily gastrointestinal and mild in severity.

Conclusions

Ibrexafungerp provides a promising safe and efficacious oral treatment that mechanistically differs from current azole treatment options for acute VVC.

Complementary Medicine and Self-Care Strategies in Women with (Recurrent) Urinary Tract and Vaginal Infections: A Cross-Sectional Study on Use and Perceived Effectiveness in The Netherlands

Due to the excessive use of antibiotic and antimycotic treatments, the risk of resistant microbes and fungi is rapidly emerging. Previous studies have demonstrated that many women with (recurrent) urinary tract infection (UTI) and/or vaginal infections (VIs) welcome alternative management approaches to reduce the use of antibiotics and antifungals and avoid short- and long-term adverse effects. This study aims to determine which complementary medicine (CM) and self-care strategies are being used by women suffering from (recurrent) UTI and VI in The Netherlands and how they perceive their effectiveness in order to define directions for future research on safety, cost-effectiveness, and implementation of best practices. A cross-sectional online survey was performed among women, ≥18 years old, with a history of UTIs; 162 respondents were included in the data analysis, with most participants aged between 50 and 64 years (36.4%). The women reported having consulted a CM practitioner for UTI-specific symptoms (23.5%) and VI-specific symptoms (13.6%). Consultations of homeopaths, acupuncturists, and herbal physicians are most often reported. Overall, 81.7% of the women suffering from UTI used complementary or self-care strategies besides regular treatment, and 68.7% reported using CM/self-care strategies to treat vaginal symptoms. UTI- related use of cranberries (51.9%), vitamin C (43.8%), and D-mannose (32.7%) were most reported. Perceived effectiveness was mostly reported for homeopathic remedies and D-mannose. The results showed a substantial burden of UTI and VI on daily and sexual activities. Besides the frequency of use, the indication of perceived effectiveness seems to be an important parameter for further and rigorously designed research to encourage nonantibiotic/antifungal treatment implementation into daily clinical practice.

Antimicrobial Susceptibility Testing of Metronidazole and Clindamycin against Gardnerella vaginalis in Planktonic and Biofilm Formation

Background

Bacterial vaginosis (BV), one of the most common vaginal ecosystem-related microbiologic syndromes, is the most common disorder in women of reproductive age. Gardnerella (G.) vaginalis is the predominant species causing this infection. Our aim was to compare the antimicrobial susceptibilities of metronidazole and clindamycin against G. vaginalis at planktonic and biofilm levels.

Methods

From September 2019 to October 2019, we recruited a total of 10 patients with BV who underwent gynecological examinations at Beijing Obstetrics and Gynecology Hospital. G. vaginalis isolates were obtained from the vagina and identified using their characteristic colony morphology. Sequence data of clinical G. vaginalis isolates were confirmed by comparing 16S rDNA sequences. Subsequently, clinical isolates were evaluated for antimicrobial susceptibilities in vitro to metronidazole and clindamycin at planktonic and biofilm levels. The minimum inhibitory concentration (MIC) for metronidazole and clindamycin was evaluated by antimicrobial susceptibility testing. The minimum biofilm eradication concentration (MBEC) was evaluated by the biofilm inhibition assay.

Results

Planktonic clinical isolates showed a significantly higher susceptibility rate (76.67%) and lower resistance rate (23.33%) to clindamycin than to metronidazole (susceptibility rate: 38.24%; resistance rate: 58.82%; P < 0.05 for both). Furthermore, in comparison to planktonic isolates, the minimum inhibitory concentration (MIC) of metronidazole was significantly higher for biofilm-forming isolates (7.3 ± 2.6 μg/mL vs. 72.4 ± 18.3 μg/mL; P=0.005); the resistance rate was 27.3%, and the minimum biofilm eradication concentration (MBEC) was >128 μg/mL. Moreover, the MIC of clindamycin was higher too for biofilm-forming isolates (0.099 ± 0.041 μg/mL vs. 23.7 ± 9.49 μg/mL; P=0.034); the resistance rate was 27.3%, and the MBEC of clindamycin was 28.4 ± 6.50 μg/mL.

Conclusion

Our results indicate that in comparison to metronidazole, clindamycin seems to be a better choice to tackle G. vaginalis as it exhibits a relatively higher susceptibility rate and lower resistance rate.