Mary L. Delaney

Enterobacteriaceae Act in Concert with the Gut Microbiota to Induce Spontaneous and Maternally Transmitted Colitis

Disruption of homeostasis between the host immune system and the intestinal microbiota leads to inflammatory bowel disease (IBD). Whether IBD is instigated by individual species or disruptions of entire microbial communities remains controversial. We characterized the fecal microbial communities in the recently described T-bet(-/-) ×Rag2(-/-) ulcerative colitis (TRUC) model driven by T-bet deficiency in the innate immune system. 16S rRNA-based analysis of TRUC and Rag2(-/-) mice revealed distinctive communities that correlate with host genotype. The presence of Klebsiella pneumoniae and Proteus mirabilis correlates with colitis in TRUC animals, and these TRUC-derived strains can elicit colitis in Rag2(-/-) and WT adults but require a maternally transmitted endogenous microbial community for maximal intestinal inflammation. Cross-fostering experiments indicated a role for these organisms in maternal transmission of disease. Our findings illustrate how gut microbial communities work in concert with specific culturable colitogenic agents to cause IBD.

Bifidobacterium animalis subsp. lactis fermented milk product reduces inflammation by altering a niche for colitogenic microbes

Intestinal health requires the coexistence of eukaryotic self with the gut microbiota and dysregulated host-microbial interactions can result in intestinal inflammation. Here, we show that colitis improved in T-bet−/−Rag2−/− mice that consumed a fermented milk product containing Bifidobacterium animalis subsp. lactis DN-173 010 strain. A decrease in cecal pH and alterations in short chain fatty acid profiles occurred with consumption, and there were concomitant increases in the abundance of select lactate-consuming and butyrate-producing bacteria. These metabolic shifts created a nonpermissive environment for the Enterobacteriaceae recently identified as colitogenic in a T-bet−/−Rag2−/− ulcerative colitis mouse model. In addition, 16S rRNA-based analysis of the T-bet−/−Rag2−/−fecal microbiota suggest that the structure of the endogenous gut microbiota played a key role in shaping the host response to the bacterial strains studied herein. We have identified features of the gut microbiota, at the membership and functional level, associated with response to this B. lactis-containing fermented milk product, and therefore this model provides a framework for evaluating and optimizing probiotic-based functional foods.

Detection of bacteria in placental tissues obtained from extremely low gestational age neonates.

OBJECTIVE The objective of the study was to quantify and identify aerobic and anaerobic bacteria as well as Mycoplasma and Ureaplasma in the chorionic parenchyma. STUDY DESIGN A sample of the chorionic parenchyma from neonates delivered between 23-27 completed weeks was cultured and tested by polymerase chain reaction (PCR) methods using universal bacterial primers for the presence of bacteria and mycoplasmas. RESULTS The culture positive rate was higher for vaginal deliveries (333/489; 68%) than for cesarean sections (363/876; 41%). Thirty percent of all culture-positive samples had only aerobic bacteria, 21% of the samples had only anaerobic bacteria, and 9% of the samples had only Mycoplasma/Ureaplasma. The mean concentration of Mycoplasma/Ureaplasma (4.00 +/- 1.11 log10 CFU/g) was significantly higher (P < .001) than the total count of either aerobes (3.24 +/- 1.12 log10 CFU/g) or anaerobes (2.89 +/- 0.99 log10 CFU/g). Staphylococcus sp. and Corynebacterium sp. as well as organisms associated with bacterial vaginosis were the most frequently recovered. A PCR product was not detected from either randomly selected or known culture-positive samples. CONCLUSION Approximately half of second-trimester placentas harbor organisms within the chorionic plate. The chorion parenchyma appears to harbor constituents that prevent the identification of bacterial deoxyribonucleic acid by PCR methods.

Colonization of second trimester placenta parenchyma

OBJECTIVE The overtly healthy, nonpregnant uterus harbors bacteria, Mycoplasma and Ureaplasma. The extent of colonization remains elusive, as are relationships between isolated microorganisms, preterm labor and fetal inflammation. STUDY DESIGN Biopsy specimens of chorion parenchyma from 1083 placentas delivered before the beginning of the 28th week of gestation were cultured, and the placentas were examined histologically. The frequencies of individual microorganisms and groups of microorganisms were evaluated in strata of processes leading to preterm delivery, routes of delivery, gestational age, and placenta morphology. RESULTS Placentas delivered by cesarean section with preeclampsia had the lowest bacterial recovery rate (25%). Preterm labor had the highest rates, which decreased with increasing gestational age from 79% at 23 weeks to 43% at 27 weeks. The presence of microorganisms in placenta parenchyma was associated with the presence of neutrophils in the fetal stem vessels of the chorion or in the vessels of the umbilical cord. CONCLUSION The high rate of colonization appears to coincide with phenomena associated with preterm delivery and gestational age. The presence of microorganisms within placenta parenchyma is biologically important.

Prevalence of Toxic Shock Syndrome Toxin 1-Producing Staphylococcus aureus and the Presence of Antibodies to This Superantigen in Menstruating Women

ABSTRACT Menstrual toxic shock syndrome (mTSS) is thought to be associated with colonization with toxic shock syndrome toxin 1 (TSST-1)-producing Staphylococcus aureus in women with insufficient antibody titers. mTSS has been associated with menstruation and tampon use, and although it is rare, the effects can be life threatening. It remains of interest because of the widespread use of tampons, reported to be about 70% of women in the United States, Canada, and much of Western Europe. This comprehensive study was designed to determine S. aureus colonization and TSST-1 serum antibody titers in 3,012 menstruating women in North America between the ages of 13 and 40, particularly among age and racial groups that could not be assessed reliably in previous small studies. One out of every four subjects was found to be colonized with S. aureus in at least one of three body sites (nose, vagina, or anus), with approximately 9% colonized vaginally. Eighty-five percent of subjects had antibody titers (≥1:32) to TSST-1, and the vast majority (81%) of teenaged subjects (13 to 18 years) had already developed antibody titers. Among carriers of toxigenic S. aureus, a significantly lower percentage of black women than of white or Hispanic women were found to have antibody titers (≥1:32) to TSST-1 (89% versus 98% and 100%). These findings demonstrate that the majority of teenagers have antibody titers (≥1:32) to TSST-1 and are presumed to be protected from mTSS. These findings also suggest that black women may be more susceptible to mTSS than previously thought.

Maternal Microbe-Specific Modulation of Inflammatory Response in Extremely Low-Gestational-Age Newborns

ABSTRACT The fetal response to intrauterine inflammatory stimuli appears to contribute to the onset of preterm labor as well as fetal injury, especially affecting newborns of extremely low gestational age. To investigate the role of placental colonization by specific groups of microorganisms in the development of inflammatory responses present at birth, we analyzed 25 protein biomarkers in dry blood spots obtained from 527 newborns delivered by Caesarean section in the 23rd to 27th gestation weeks. Bacteria were detected in placentas and characterized by culture techniques. Odds ratios for having protein concentrations in the top quartile for gestation age for individual and groups of microorganisms were calculated. Mixed bacterial vaginosis (BV) organisms were associated with a proinflammatory pattern similar to those of infectious facultative anaerobes. Prevotella and Gardnerella species, anaerobic streptococci, peptostreptococci, and genital mycoplasmas each appeared to be associated with a different pattern of elevated blood levels of inflammation-related proteins. Lactobacillus was associated with low odds of an inflammatory response. This study provides evidence that microorganisms colonizing the placenta provoke distinctive newborn inflammatory responses and that Lactobacillus may suppress these responses. IMPORTANCE Despite improved intensive care, preterm and especially extremely low-gestation-age neonates continue to be at a considerably increased risk of morbidity, mortality, and developmental problems. The fetal inflammatory response appears to contribute to the onset of preterm labor, fetal injury, and complications, underlying lifetime health challenges facing these children. This study provides evidence that bacterial colonization of the very preterm placenta is associated with distinct microorganism-specific inflammatory protein profiles in the newborn blood specimens. We also provide evidence that Lactobacillus reduces inflammatory responses in newborns. Our data support the concept that targeting of placental colonization by specific drugs or probiotics during early pregnancy holds promise for preventing not only preterm birth but also subsequent and long-lasting, inflammation-provoked late sequelae. Despite improved intensive care, preterm and especially extremely low-gestation-age neonates continue to be at a considerably increased risk of morbidity, mortality, and developmental problems. The fetal inflammatory response appears to contribute to the onset of preterm labor, fetal injury, and complications, underlying lifetime health challenges facing these children. This study provides evidence that bacterial colonization of the very preterm placenta is associated with distinct microorganism-specific inflammatory protein profiles in the newborn blood specimens. We also provide evidence that Lactobacillus reduces inflammatory responses in newborns. Our data support the concept that targeting of placental colonization by specific drugs or probiotics during early pregnancy holds promise for preventing not only preterm birth but also subsequent and long-lasting, inflammation-provoked late sequelae.

Characterization of Chorioamnionitis in 2nd-Trimester C-Section Placentas and Correlation with Microorganism Recovery from Subamniotic Tissues

Prolonged exposure to infection appears to influence fetal/neonatal development. We characterize the relationship between histologic patterns of inflammation and microorganism recovery from the placentas of live born infants delivered before the 28th postmenstrual week. The subamniotic parenchyma of 835 placentas delivered by cesarean section were cultured and evaluated for specific histologic patterns of inflammation in a blinded fashion. Cases with prolonged membrane rupture were excluded. Microorganisms were recovered from 41% of placentas. Microorganisms found more frequently in placentas with high-grade chorionic plate inflammation include Actinomyces, Prevotella bivia, Corynebacterium sp., Escherichia coli, Peptostreptococcus magnus, multiple species of Streptococci, and Mycoplasma sp., including Ureaplasma urealyticum. These microorganisms were also associated with fetal vasculitis (neutrophilic infiltration of chorionic plate stem vessels or umbilical cord). Recovery of microorganisms from placental parenchyma is associated with histologic inflammation. The same microorganisms responsible for inciting high-grade chorionic plate inflammation are also most likely to promote fetal inflammation.

Mode of delivery and cord blood cytokines: a birth cohort study

BackgroundThe mechanisms for the association between birth by cesarean section and atopy and asthma are largely unknown.ObjectiveTo examine whether cesarean section results in neonatal secretion of cytokines that are associated with increased risk of atopy and/or asthma in childhood. To examine whether the association between mode of delivery and neonatal immune responses is explained by exposure to the maternal gut flora (a marker of the vaginal flora).MethodsCBMCs were isolated from 37 neonates at delivery, and secretion of IL-13, IFN-γ, and IL-10 (at baseline and after stimulation with antigens [dust mite and cat dander allergens, phytohemagglutinin, and lipopolysaccharide]) was quantified by ELISA. Total and specific microbes were quantified in maternal stool. The relation between mode of delivery and cord blood cytokines was examined by linear regression. The relation between maternal stool microbes and cord blood cytokines was examined by Spearmans correlation coefficients.ResultsCesarean section was associated with increased levels of IL-13 and IFN-γ. In multivariate analyses, cesarean section was associated with an increment of 79.4 pg/ml in secretion of IL-13 by CBMCs after stimulation with dust mite allergen (P < 0.001). Among children born by vaginal delivery, gram-positive anaerobes and total anaerobes in maternal stool were positively correlated with levels of IL-10, and gram-negative aerobic bacteria in maternal stool were negatively correlated with levels of IL-13 and IFN-γ.ConclusionCesarean section is associated with increased levels of IL-13 and IFN-γ, perhaps because of lack of labor and/or reduced exposure to specific microbes (e.g., gram-positive anaerobes) at birth.

The Human Microbiome during Bacterial Vaginosis

SUMMARY 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.

Novel Vaginal Microflora Colonization Model Providing New Insight into Microbicide Mechanism of Action

ABSTRACT Several broad-spectrum microbicides, including cellulose sulfate (CS), have passed conventional preclinical and phase I clinical safety evaluation and yet have failed to protect women from acquiring HIV-1 in phase II/III trials. Concerns have been raised that current preclinical algorithms are deficient in addressing the complexity of the microflora-regulated vaginal mucosal barrier. We applied a novel microflora-colonized model to evaluate CS and hydroxyethylcellulose (HEC), which is used as a “universal placebo” in microbicide trials. Cervicovaginal epithelial cultures were colonized with normal vaginal microflora isolates representing common Lactobacillus species used as probiotics (L. acidophilus and L. crispatus) or Prevotella bivia and Atopobium vaginae, most prevalent in the disturbed microflora of bacterial vaginosis (BV). At baseline, all strains maintained constant epithelium-associated CFUs without inducing cytotoxicity and apoptosis. CS selectively reduced epithelium-associated CFUs and (to a lesser extent) planktonic CFUs, most significantly affecting L. crispatus. Inducing only minor changes in sterile epithelial cultures, CS induced expression of innate immunity mediators (RANTES, interleukin-8 [IL-8], and secretory leukocyte protease inhibitor [SLPI]) in microflora-colonized epithelia, most significantly potentiating effects of bacteria causing BV. In the absence of CS, all bacterial strains except L. acidophilus activated NF-κB, although IL-8 and RANTES levels were increased by the presence of BV-causing bacteria only. CS enhanced NF-κB activation in a dose-dependent manner under all conditions, including L. acidophilus colonization. HEC remained inert. These results offer insights into possible mechanisms of CS clinical failure. The bacterially colonized cervicovaginal model reveals unique aspects of microflora-epithelium-drug interactions and innate immunity in the female genital tract and should become an integral part of preclinical safety evaluation of anti-HIV microbicides and other vaginal formulations. IMPORTANCE This report provides experimental evidence supporting the concept that the vaginal microflora regulates the epithelial innate immunity in a species- and strain-specific manner and that topically applied microbicides may alter both the bacterial and epithelial components of this homeostatic interaction. Our data also highlight the importance of differentiating the effects of biomedical interventions on epithelium-associated versus conventional planktonic bacterial growth when assessing vaginal mucosal health and immunity. This report provides experimental evidence supporting the concept that the vaginal microflora regulates the epithelial innate immunity in a species- and strain-specific manner and that topically applied microbicides may alter both the bacterial and epithelial components of this homeostatic interaction. Our data also highlight the importance of differentiating the effects of biomedical interventions on epithelium-associated versus conventional planktonic bacterial growth when assessing vaginal mucosal health and immunity.