Smoking in women with chronic vaginal discomfort is not associated with decreased abundance of Lactobacillus spp. but promotes Mobiluncus and Gardnerella spp. overgrowth - secondary analysis of trial data including microbio-me analysis.

BACKGROUND: Smoking is considered a risk factor for bacterial vaginosis. It is currently unknown which parameters of the vaginal environment are affected and how smoking triggers the disease. AIM OF THE STUDY: The primary objective is to estimate the effect size of smoking on vaginal pH and the Nugent score in patients with chronic vulvovaginal discomfort prior to the development of episode of vaginosis. The secondary goal is to investigate the effect of smoking on individual microscopic parameters of the vaginal environment and on subjectively reported symptoms of vaginal discomfort. METHODS: Smoking reported by patients was tested as a predictor, using multivariate logistic and ordinal logistic regression analysis on a dataset from the first visit of a randomized trial NCT04171947, which enrolled patients with intermediate vaginal environment. We tested the primary hypothesis (odds ratio (OR) for vaginal pH > 4.5 and Nugent score > 3 in smokers) at the significance level á = 5%. For exploratory analyses of the effect of smoking on the parameters of the vaginal environment, á was corrected as per Bonferoni. RESULTS: In a cross-sectional sample of 250 women after adjusting for other risk factors, smoking had an impact on the Nugent score (OR = 3.3 (1.3-8.5), P = 0.011), while pH was not affected (OR = 1.2 (0.5-2.8), P = 0.698). Smoking was associated with the prevalence of clue cells (P < 0.000), Gardnerella spp. (P = 0.001) and Mobiluncus spp. (P = 0.001), while the prevalence of Lactobacillus remained unchanged (P = 0.049). CONCLUSION: Contrarily to common assumptions, vaginal Lactobacillus is not directly affected by smoking, which rather promotes the growth of bacteria of Gardnerella and Mobiluncus spp. Given that other parameters remained unaffected, it appears that smoking leads to vaginal dysbio-sis by creating specific favourable conditions for these two opportunistic  pathogens.

Identification of bilirubin reduction products formed by Clostridium perfringens isolated from human neonatal fecal flora.

Urobilinoids belong to the heterogenous group of degradation products of bilirubin formed in the gastrointestinal tract by intestinal microflora. Among them urobilinogen and stercobilinogen with their respective oxidation products, urobilin and stercobilin, are the most important compounds. The aim of present study was to analyze the products of bacterial reduction of bilirubin in more detail. The strain of Clostridium perfringens isolated from neonatal stools, capable of reducing bilirubin, was used in the study. Bacteria were incubated under anaerobic conditions with various native as well as synthetic bile pigments, including radiolabeled unconjugated bilirubin (UCB). Their reduction products were extracted from media and separated following thin layer chromatography. Pigments isolated were analyzed by spectrophotometry, spectrofluorometry and mass spectrometry. In a special set of experiments, bilirubin diglucuronide was incubated with either bacterial lysate or partially purified bilirubin reductase and beta-glucuronidase to reveal whether bilirubin glucuronides may be directly reduced onto conjugated urobilinoids. A broad substrate activity was detected in the investigated strain of C. perfringens and a series of bilirubin reduction products was identified. These products were separated in the form of their respective chromogens and further oxidized. Based on their physical-chemical properties, as well as mass spectra, end-catabolic bilirubin products were identified to belong to urobilinogen species. The reduction process, catalyzed enzymatically by the studied bacterial strain, does not proceed to stercobilinogen. Bilirubin diglucuronide is not reduced onto urobilinoid conjugates, glucuronide hydrolysis must precede double bond reduction and thus UCB is reduced much faster.

The impact of intestinal microflora on serum bilirubin levels.

BACKGROUND/AIMS: Intestinal microflora plays an important role in the pathogenesis of neonatal jaundice by inhibiting enterosystemic circulation of bilirubin. The present study aimed to investigate the influence of intestinal microflora on serum bilirubin levels in hyperbilirubinemic Gunn rats. METHODS: After a baseline phase Gunn rats received oral antibiotics (either clindamycin/neomycine or co-trimethoxazole for four days, phase II). Intestinal colonization was carried out either with a bilirubin-reducing strain of C. perfringens or C. pasteurianum incapable of reducing bilirubin (phase III). Serum bilirubin and fecal bile pigments were determined at the end of each phase. RESULTS: Oral administration of clindamycin/neomycine resulted in the disappearance of fecal urobilinoids. Simultaneously, serum bilirubin increased dramatically (186+/-31 vs. 289+/-35 micromol/l, P=0.004). Intestinal colonization with C. perfringens led to reappearance of fecal urobilinoid production accompanied with a partial decrease of serum bilirubin (289+/-35 vs. 239+/-17 micromol/l, P=0.013), whereas the effect of C. pasteurianum on bile pigment metabolism was negligible. Co-trimethoxazole therapy had no effect on serum and intestinal metabolism of bilirubin. CONCLUSIONS: Intestinal microflora greatly affects intravascular metabolism of bilirubin. Prolonged use of certain antibiotics in man may lead to an increase in serum bilirubin levels, while the enhancement of intestinal catabolism may have an opposite effect.

The effect of zinc salts on serum bilirubin levels in hyperbilirubinemic rats.

OBJECTIVES: Intestinal metabolism of bilirubin is implicated in the pathogenesis of neonatal jaundice and Crigler-Najjar syndrome. In the present study the authors investigated the effect of oral administration of zinc salts on serum bilirubin levels in hyperbilirubinemic rats. METHODS: Bilirubin-binding activities of zinc sulfate and water-insoluble zinc methacrylate were determined in vitro. Congenitally hyperbilirubinemic Gunn rats and artificially hyperbilirubinemic Wistar rats were used in in vivo studies. Animals were fed a normal diet for 1 week and then a treatment diet of either zinc sulfate or zinc methacrylate for additional 2 weeks. Serum and fecal bile pigments were determined at the end of each phase. Biliary bilirubin secretion rates were determined in hyperbilirubinemic Wistar rats fed zinc methacrylate. RESULTS: Substantial bilirubin-binding activities of zinc salts were demonstrated in in vitro experiments. Treatment with oral zinc salts significantly decreased serum bilirubin levels in Gunn rats (166 +/- 53 versus 123 +/- 38 and 206 +/- 34 versus 131 +/- 31 micromol/L, P < 0.05 for zinc methacrylate and zinc sulfate, respectively). A similar effect of zinc methacrylate was also observed in hyperbilirubinemic Wistar rats (102 +/- 10 versus 14 +/- 4 micromol/L, P < 0.0001). In accord, biliary bilirubin secretion decreased significantly in these animals (45 +/- 11 versus 28 +/- 4 nmol/h 100g body weight, P < 0.02). In contrast to zinc sulfate, treatment with zinc methacrylate did not lead to the elevation of serum zinc levels. CONCLUSIONS: Oral administration of zinc salts efficiently decreased serum bilirubin levels in hyperbilirubinemic rats, presumably as a result of inhibition of enterohepatic circulation of bilirubin. This approach might be useful in the treatment of severe unconjugated hyperbilirubinemias.