Use of DNA hybridization to detect vaginal pathogens associated with bacterial vaginosis among asymptomatic pregnant women

Identification of Therapeutic Targets in an Emerging Gastrointestinal Pathogen Campylobacter ureolyticus and Possible Intervention through Natural Products

Campylobacter ureolyticus is a Gram-negative, anaerobic, non-spore-forming bacteria that causes gastrointestinal infections. Being the most prevalent cause of bacterial enteritis globally, infection by this bacterium is linked with significant morbidity and mortality in children and immunocompromised patients. No information on pan-therapeutic drug targets for this species is available yet. In the current study, a pan-genome analysis was performed on 13 strains of C. ureolyticus to prioritize potent drug targets from the identified core genome. In total, 26 druggable proteins were identified using subtractive genomics. To the best of the authors’ knowledge, this is the first report on the mining of drug targets in C. ureolyticus. UDP-3-O-acyl-N-acetylglucosamine deacetylase (LpxC) was selected as a promiscuous pharmacological target for virtual screening of two bacterial-derived natural product libraries, i.e., postbiotics (n = 78) and streptomycin (n = 737) compounds. LpxC inhibitors from the ZINC database (n = 142 compounds) were also studied with reference to LpxC of C. ureolyticus. The top three docked compounds from each library (including ZINC26844580, ZINC13474902, ZINC13474878, Notoginsenoside St-4, Asiaticoside F, Paraherquamide E, Phytoene, Lycopene, and Sparsomycin) were selected based on their binding energies and validated using molecular dynamics simulations. To help identify potential risks associated with the selected compounds, ADMET profiling was also performed and most of the compounds were considered safe. Our findings may serve as baseline information for laboratory studies leading to the discovery of drugs for use against C. ureolyticus infections.

Renal and perinephric abscesses involving Lactobacillus jensenii and Prevotella bivia in a young woman following ureteral stent procedure

 is a gram-positive bacillus in the female genital tract believed to be a commensal organism that inhibits the growth of more virulent pathogens. Prevotella bivia is a gram-negative bacillus species also typically commensal in the female genital tract. Lactobacillus as the primary causative agent in perinephric abscesses and bacteremia has been documented, albeit very uncommon and opportunistic. Prevotella bivia is not classically associated with perinephric abscesses but has been implicated in rare cases of pelvic inflammatory disease and tubo-ovarian abscesses. In this report, we present a 26-year-old immunocompetent woman with a recent history of nephrolithiasis treated with lithotripsy, ureteral stent placement and removal, and antibiotics who was admitted for fever and severe right flank pain. Imaging showed a right-sided renal and perinephric abscesses colonized by Lactobacillus jensenii and Prevotella bivia. Blood cultures were also positive for Lactobacillus species. Per literature review, intravenous ceftriaxone and metronidazole were administered with successful resolution of abscesses and negative repeat blood cultures. To our knowledge, this is the first case of simultaneous renal system abscesses caused by Lactobacillus and Prevotella species. Nephrolithiasis and prior antibiotics likely contributed to the opportunistic pathogenesis in this otherwise immunocompetent patient.

The Human Microbiome during Bacterial Vaginosis

Bacterial vaginosis (BV) is the most commonly reported microbiological syndrome among women of childbearing age. BV is characterized by a shift in the vaginal flora from the dominant Lactobacillus to a polymicrobial flora. BV has been associated with a wide array of health issues, including preterm births, pelvic inflammatory disease, increased susceptibility to HIV infection, and other chronic health problems. A number of potential microbial pathogens, singly and in combinations, have been implicated in the disease process. The list of possible agents continues to expand and includes members of a number of genera, including Gardnerella, Atopobium, Prevotella, Peptostreptococcus, Mobiluncus, Sneathia, Leptotrichia, Mycoplasma, and BV-associated bacterium 1 (BVAB1) to BVAB3. Efforts to characterize BV using epidemiological, microscopic, microbiological culture, and sequenced-based methods have all failed to reveal an etiology that can be consistently documented in all women with BV. A careful analysis of the available data suggests that what we term BV is, in fact, a set of common clinical signs and symptoms that can be provoked by a plethora of bacterial species with proinflammatory characteristics, coupled to an immune response driven by variability in host immune function.

Treatment and Management of Bacterial Vaginosis in Pregnancy: Current and Future Perspectives

Bacterial vaginosis accounts for the majority of cases of vaginal discharge and has been consistently linked to an increased risk of preterm delivery. Bacterial vaginosis is characterized by the reduced number or absence of hydrogen peroxide-producing Lactobacillus spp., which promotes the overgrowth of anaerobic bacteria, including Gardnerella vaginalis, Mycoplasma hominis, Bacteroides spp., and Mobiluncus spp. Black race, higher-risk sexual activity, frequent vaginal douching and the substantial reduction of hydrogen peroxide-producing Lactobacillus spp. are the main predictors of bacterial vaginosis development. Clinical- and laboratory-based bacterial vaginosis diagnostic tests are widely used to screen for bacterial vaginosis but, more recently, office-based bacterial vaginosis screening tools have been developed. Although systemic treatment for bacterial vaginosis with metronidazole or clindamycin has been demonstrated to be effective in the short-term cure of bacterial vaginosis, recurrence of bacterial vaginosis within 3 months of treatment is common, and treatment for bacterial vaginosis using these strategies has not been effective in reducing the risk of preterm delivery.

Anaerobes and bacterial vaginosis in pregnancy: virulence factors contributing to vaginal colonisation

The aetiology and pathogenesis of bacterial vaginosis (BV) is unclear but it appears to be associated with factors that disrupt the normal acidity of the vagina thus altering the equilibrium between the normal vaginal microbiota. BV has serious implications for female morbidity, including reports of pelvic inflammatory disease, adverse pregnancy outcomes, increased susceptibility to sexually transmitted infections and infertility. This paper reviewed new available information regarding possible factors contributing to the establishment of the BV vaginal biofilm, examined the proposed role of anaerobic microbial species recently detected by new culture-independent methods and discusses developments related to the effects of BV on human pregnancy. The literature search included Pubmed (NLM), LISTA (EBSCO), and Web of Science. Because of the complexity and diversity of population groups, diagnosis and methodology used, no meta-analysis was performed. Several anaerobic microbial species previously missed in the laboratory diagnosis of BV have been revealed while taking cognisance of newly proposed theories of infection, thereby improving our understanding and knowledge of the complex aetiology and pathogenesis of BV and its perceived role in adverse pregnancy outcomes.

Infection and fetal loss in the mid-second trimester of pregnancy

INTRODUCTION

Chorioamnionitis is a common cause of second trimester pregnancy loss, usually due to ascending infection. This study investigates the prevalence and bacteriology of chorioamnionitis in cases of spontaneous pregnancy loss in previable gestations (16-22 weeks).

METHODS

Fetal losses between 16- and 22-week gestation were identified from the institutional database over a three-year period. Cases with an autopsy were identified, pathology reports reviewed, and maternal features noted (clinical symptoms, blood count and vaginal culture results). Second trimester medical termination for fetal abnormality during the same time period served as controls for the confounding influence of labour.

RESULTS

A total of 101 cases of spontaneous non-anomalous non-macerated fetal losses and 103 control cases of induced loss for fetal anomaly were identified. Median gestation of cases was 19 weeks (interquartile range (IQR) 17, 21) and of controls was 20 weeks (IQR 19, 21). Maternal white cell count was higher in cases (median 13.6 IQR 10.8, 16.6) than in controls (9.9 IQR 7.6, 11.5) (P < 0.01). Seventy-eight (77.2%) of 101 cases and no controls had histological chorioamnionitis. A fetal reaction was identified in 48.7% of cases with chorioamnionitis, and the frequency of fetal reaction increased as gestation advanced (5.3% at 16-week gestation vs 33.3% at 22-week gestation). In cases with chorioamnionitis 36/76 (47.4%) were culture positive, whereas 4/25 (16%) without chorioamnionitis were culture positive.

CONCLUSION

In otherwise normal fetuses, chorioamnionitis is a common finding in mid-trimester pregnancy loss. Routine culture methods have a low sensitivity for isolation of the causative micro-organisms. This inflammatory process seems to predate the onset of labour and appears a primary mechanism in the aetiology of such losses.

Vaginal and oral microbes, host genotype and preterm birth

Preterm birth (PTB) is a leading cause of infant mortality and morbidity in the US and across the globe. Infection and associated inflammation are important initiators for PTB pathways; an estimated 40% of PTBs are attributed to amniochorionic-decidual or systemic inflammation. Historically, intrauterine infections have been implicated in PTB; recent evidence suggests that infections remote from the fetal site may also be causative. There is strong epidemiological evidence that bacterial vaginosis and periodontitis--two syndromes characterized by perturbations in the normal vaginal and oral bacterial microflora, respectively--are linked to infection-associated PTB. Oral and vaginal environments are similar in their bacterial microbiology; identical bacterial species have been independently isolated in periodontitis and bacterial vaginosis. Periodontitis and bacterial vaginosis also share many behavioral and sociodemographic risk factors suggesting a possible common pathophysiology. Genetic polymorphisms in host inflammatory responses to infection are shared between bacterial vaginosis, periodontitis and PTB, suggesting common mechanisms through which host genotype modify the effect of abnormal bacterial colonization on preterm birth. We review the state of knowledge regarding the risk of PTB attributable to perturbations in bacterial flora in oral and vaginal sites and the role of host genetics in modifying the risk of infection-related PTB. We posit that bacterial species that are common in perturbed vaginal and oral sites are associated with PTB through their interaction with the host immune system.

Guidelines for the treatment of bacterial vaginosis: focus on tinidazole

Bacterial vaginosis (BV) is a complex vaginal infection most commonly associated with women of child-bearing age. Risk factors for BV are numerous. There are currently multiple clinical and laboratory tests for diagnosis of BV, including the most commonly used diagnostic methods: Amsel’s criteria or Nugent’s Gram stain scale. The mainstay of BV therapy is metronidazole, but tinidazole as well as a few other agents have also been used successfully. Tinidazole is the second nitroimidazole antiprotozoal agent and a structural derivative of metronidazole. With a favorable pharmacokinetic profile and reduced side effects, tinidazole is an alternative agent for BV treatment. There are minimal head-to-head comparative data to establish tinidazole’s superiority to metronidazole or other therapeutic agents. Available data suggest tinidazole has a role in special populations particularly for refractory or relapsing BV.

The vaginal microflora in relation to gingivitis

BACKGROUND

Gingivitis has been linked to adverse pregnancy outcome (APO). Bacterial vaginosis (BV) has been associated with APO. We assessed if bacterial counts in BV is associated with gingivitis suggesting a systemic infectious susceptibilty.

METHODS

Vaginal samples were collected from 180 women (mean age 29.4 years, SD +/- 6.8, range: 18 to 46), and at least six months after delivery, and assessed by semi-quantitative DNA-DNA checkerboard hybridization assay (74 bacterial species). BV was defined by Gram stain (Nugent criteria). Gingivitis was defined as bleeding on probing at >or= 20% of tooth sites.

RESULTS

A Nugent score of 0-3 (normal vaginal microflora) was found in 83 women (46.1%), and a score of > 7 (BV) in 49 women (27.2%). Gingivitis was diagnosed in 114 women (63.3%). Women with a diagnosis of BV were more likely to have gingivitis (p = 0.01). Independent of gingival conditions, vaginal bacterial counts were higher (p < 0.001) for 38/74 species in BV+ in comparison to BV- women. Counts of four lactobacilli species were higher in BV- women (p < 0.001). Independent of BV diagnosis, women with gingivitis had higher counts of Prevotella bivia (p < 0.001), and Prevotella disiens (p < 0.001). P. bivia, P. disiens, M. curtisii and M. mulieris (all at the p < 0.01 level) were found at higher levels in the BV+/G+ group than in the BV+/G- group. The sum of bacterial load (74 species) was higher in the BV+/G+ group than in the BV+/G- group (p < 0.05). The highest odds ratio for the presence of bacteria in vaginal samples (> 1.0 x 104 cells) and a diagnosis of gingivitis was 3.9 for P. bivia (95% CI 1.5-5.7, p < 0.001) and 3.6 for P. disiens (95%CI: 1.8-7.5, p < 0.001), and a diagnosis of BV for P. bivia (odds ratio: 5.3, 95%CI: 2.6 to 10.4, p < 0.001) and P. disiens (odds ratio: 4.4, 95% CI: 2.2 to 8.8, p < 0.001).

CONCLUSION

Higher vaginal bacterial counts can be found in women with BV and gingivitis in comparison to women with BV but not gingivitis. P. bivia and P. disiens may be of specific significance in a relationship between vaginal and gingival infections.

The Pap smear for detection of bacterial vaginosis

OBJECTIVE

To assess validity of Pap smears in diagnosing bacterial vaginosis.

METHOD

A prospective diagnostic accuracy study with 533 women in Mombasa, Kenya. Diagnosis of bacterial vaginosis using clinical observations scored with simplified Amsel's criteria and Bethesda system for Pap smears was compared with a reference standard (Nugent criteria for gram stains). Both laboratory tests were interpreted blindly.

RESULT

Bacterial vaginosis prevalence was 36.7% (191/521) with Nugent criteria. Pap smear sensitivity and specificity were 59.4% (111/187) and 83.3% (270/324), with corresponding figures for simplified Amsel's criteria of 44.8% (81/181) and 84.8% (263/310). For Pap smear and simplified Amsel's criteria, positive predictive values were 67.3 and 63.3%, and negative predictive values 78.0% and 72.5%.

CONCLUSION

In diagnosing bacterial vaginosis, Pap smears have moderate sensitivity (though higher than simplified Amsel's criteria). Specificity of Pap smears is adequate. Including bacterial vaginosis assessment as a standard component of Pap smears warrants consideration.

The effect of polycarbophil gel (Replens™) on bacterial vaginosis: A pilot study

OBJECTIVE

To determine if use of intravaginal polycarbophil gel (Replens) for 1 month will: (1) lower vaginal pH; (2) improve signs of bacterial vaginosis (BV).

STUDY DESIGN

Seventeen women with BV self-administered polycarbophil gel every third day for 4 weeks in an open-label, prospective pilot study. Primary outcome measures included vaginal pH, presence of amines and Nugent scores.

RESULTS

At week 4, there was improvement in Nugent scores, vaginal odor and clue cell count (p<0.05). Eleven women converted from amine positive to negative (73+/-20%). There was no significant change in vaginal pH.

CONCLUSIONS

Polycarbophil gel is associated with improved signs of BV, although not vaginal pH.

Throwing the dice for the diagnosis of vaginal complaints?

BACKGROUND

Vaginitis is among the most common conditions women are seeking medical care for. Although these infections can easily be treated, the relapse rate is high. This may be due to inadequate use of the diagnostic potential.

METHODS

We evaluated the misjudgement rate of the aetiology of vaginal complaints. A total of 220 vaginal samples from women with a vaginal complaint were obtained and analysed for numbers of total lactobacilli, H2O2-producing lactobacilli, total aerobic cell counts and total anaerobic cell counts including bifidobacteria, Bacteroides spp., Prevotella spp. Additionally, the presence of Atopobium vaginae, Gardnerella vaginalis, Candida spp. and Trichomonas vaginalis was evaluated by DNA-hybridisation using the PCR and Affirm VPIII Microbial Identification Test, respectively.

RESULTS

The participating physicians diagnosed Bacterial vaginosis (BV) as origin of discomfort in 80 cases, candidiasis in 109 cases and mixed infections in 8 cases. However, a present BV, defined as lack of H2O2-lactobacilli, presence of marker organisms, such as G. vaginalis, Bacteroides spp. or Atopobium vaginae, and an elevated pH were identified in only 45 cases of the women examined. Candida spp. were detected in 46 cases. Interestingly, an elevated pH corresponded solely to the presence of Atopobium vaginae, which was detected in 11 cases.

CONCLUSION

Errors in the diagnosis of BV and candida vulvovaginitis (CV) were high. Interestingly, the cases of misjudgement of CV (77%) were more numerous than that of BV (61%). The use of Amsel criteria or microscopy did not reduce the number of misinterpretations. The study reveals that the misdiagnosis of vaginal complaints is rather high.