Vaginal bacterial load in the second trimester is associated with early preterm birth recurrence: a nested case-control study.

OBJECTIVE: To assess the association between vaginal microbiome (VMB) composition and recurrent early spontaneous preterm birth (sPTB)/preterm prelabour rupture of membranes (PPROM). DESIGN: Nested case-control study. SETTING: UK tertiary referral hospital. SAMPLE: High-risk women with previous sPTB/PPROM <34+0 weeks' gestation who had a recurrence (n = 22) or delivered at ≥37+0 weeks without PPROM (n = 87). METHODS: Vaginal swabs collected between 15 and 22 weeks' gestation were analysed by 16S rRNA gene sequencing and 16S quantitative PCR. MAIN OUTCOME MEASURE: Recurrent early sPTB/PPROM. RESULTS: Of the 109 high-risk women, 28 had anaerobic vaginal dysbiosis, with the remainder dominated by lactobacilli (Lactobacillus iners 36/109, Lactobacillus crispatus 23/109, or other 22/109). VMB type and diversity were not associated with recurrence. Women with a recurrence, compared to those without, had a higher median vaginal bacterial load (8.64 versus 7.89 log10 cells/mcl, adjusted odds ratio [aOR] 1.90, 95% CI 1.01-3.56, P = 0.047) and estimated Lactobacillus concentration (8.59 versus 7.48 log10 cells/mcl, aOR 2.35, (95% CI 1.20-4.61, P = 0.013). A higher recurrence risk was associated with higher median bacterial loads for each VMB type after stratification, although statistical significance was reached only for L. iners domination (aOR 3.44, 95% CI 1.06-11.15, P = 0.040). Women with anaerobic dysbiosis or L. iners domination had a higher median vaginal bacterial load than women with a VMB dominated by L. crispatus or other lactobacilli (8.54, 7.96, 7.63, and 7.53 log10 cells/mcl, respectively). CONCLUSIONS: Vaginal bacterial load is associated with early sPTB/PPROM recurrence. Domination by lactobacilli other than L. iners may protect women from developing high bacterial loads. Future PTB studies should quantify vaginal bacteria and yeasts. TWEETABLE ABSTRACT: Increased vaginal bacterial load in the second trimester may be associated with recurrent early spontaneous preterm birth.

Microbial Butyrate Synthesis Indicates Therapeutic Efficacy of Azathioprine in IBD Patients.

BACKGROUND AND AIMS: The microbial ecosystem seems to be an important player for therapeutic intervenption in inflammatory bowel disease [IBD]. We assessed longitudinal microbiome changes in IBD patients undergoing therapy with either azathioprine [AZA] or anti-tumour necrosis factor [anti-TNF] antibodies. We predicted the metabolic microbial community exchange and linked it to clinical outcome. METHODS: Faecal and blood samples were collected from 65 IBD patients at baseline and after 12 and 30 weeks on therapy. Clinical remission was defined as Crohn's Disease Activity Index [CDAI] < 150 in Crohn´s disease [CD], partial Mayo score <2 in ulcerative colitis [UC], and faecal calprotectin values <150 µg/g and C-reactive protein <5 mg/dl. 16S rRNA amplicon sequencing was performed. To predict microbial community metabolic processes, we constructed multispecies genome-scale metabolic network models. RESULTS: Paired Bray-Curtis distance between baseline and follow-up time points was significantly different for UC patients treated with anti-TNF antibodies. Longitudinal changes in taxa composition at phylum level showed a significant decrease of Proteobacteria and an increase of Bacteroidetes in CD patients responding to both therapies. At family level, Lactobacilli were associated with persistent disease and Bacteroides abundance with remission in CD. In-silico simulations of microbial metabolite exchange predicted a 1.7-fold higher butyrate production capacity of patients in remission compared with patients without remission [p = 0.041]. In this model, the difference in butyrate production between patients in remission and patients without remission was most pronounced in the CD group treated with AZA [p = 0.008]. CONCLUSIONS: In-silico simulation identifies microbial butyrate synthesis predictive of therapeutic efficacy in IBD.

Salmonella Virchow isolates from human and avian origins in England--molecular characterization and infection of epithelial cells and poultry.

AIMS: To characterize 12 Salmonella Virchow isolates from human and avian sources to begin to determine the genetic relationships within the serovar, determine its capacity to invade and induce inflammatory responses in human intestinal epithelial cells and investigate its ability to colonize the chicken gastrointestinal tract. METHODS AND RESULTS: Multi-Locus Sequence Typing (MLST) revealed that 11 isolates belonged to sequence type 16 (ST16). Pulsed Field Gel Electrophoresis (PFGE) grouped the isolates into two main clusters. All isolates contained genes associated with virulence determined through PCR virulotyping. All the S. Virchow isolates had the ability to invade human epithelial cells and elicit high levels of production of the pro-inflammatory chemokine interleukin-8 (IL-8). Experimental infection of poultry showed S. Virchow colonizes the caeca and spleen. CONCLUSIONS: Isolates within the serovar show high levels of genetic relatedness regardless of the source. The data indicates S. Virchow is an invasive and inflammatory serovar, consistent with its association with invasive salmonellosis in humans. SIGNIFICANCE AND IMPACT OF THE STUDY: The poultry infection experiment included in this study shows S. Virchow can colonize the gastrointestinal tract rapidly and to high levels with the chickens showing no clinical signs of infection. The asymptomatic colonization of chickens indicates an increased ability of S. Virchow to enter the food chain undetected and cause human salmonellosis which because of the invasive and inflammatory nature of S. Virchow seen during the Caco2 invasion assay and previous studies showing its invasive nature in humans and increasing resistance to antibiotics is a public health concern.