Z-form extracellular DNA is a structural component of the bacterial biofilm matrix.

Biofilms are community architectures adopted by bacteria inclusive of a self-formed extracellular matrix that protects resident bacteria from diverse environmental stresses and, in many species, incorporates extracellular DNA (eDNA) and DNABII proteins for structural integrity throughout biofilm development. Here, we present evidence that this eDNA-based architecture relies on the rare Z-form. Z-form DNA accumulates as biofilms mature and, through stabilization by the DNABII proteins, confers structural integrity to the biofilm matrix. Indeed, substances known to drive B-DNA into Z-DNA promoted biofilm formation whereas those that drive Z-DNA into B-DNA disrupted extant biofilms. Importantly, we demonstrated that the universal bacterial DNABII family of proteins stabilizes both bacterial- and host-eDNA in the Z-form in situ. A model is proposed that incorporates the role of Z-DNA in biofilm pathogenesis, innate immune response, and immune evasion.

Maternal anxiety, depression and stress affects offspring gut microbiome diversity and bifidobacterial abundances.

Uncovering mechanisms underlying fetal programming during pregnancy is of critical importance. Atypical neurodevelopment during the pre- and immediate postnatal period has been associated with long-term adverse health outcomes, including mood disorders and aberrant cognitive ability in offspring. Maternal factors that have been implicated in anomalous offspring development include maternal inflammation and tress, anxiety, and depression. One potential mechanism through which these factors perturb normal offspring postnatal development is through microbiome disruption. The mother is a primary source of early postnatal microbiome seeding for the offspring, and the transference of a healthy microbiome is key in normal neurodevelopment. Since psychological stress, mood disorders, and inflammation have all been implicated in altering maternal microbiome community structure, passing on aberrant microbial communities to the offspring that may then affect developmental outcomes. Therefore, we examined how maternal stress, anxiety and depression assessed with standardized instruments, and maternal inflammatory cytokine levels in the pre- and postnatal period are associated with the offspring microbiome within the first 13 months of life, utilizing full length 16S sequencing on infant stool samples, that allowed for species-level resolution. Results revealed that infants of mothers who reported higher anxiety and perceived stress had reduced alpha diversity. Additionally, the relative taxonomic quantitative abundances of Bifidobacterium dentium and other species that have been associated with either modulation of the gut-brain axis, or other beneficial health outcomes, were reduced in the offspring of mothers with higher anxiety, perceived stress, and depression. We also found associations between bifidobacteria and prenatal maternal pro-inflammatory cytokines IL-6, IL-8, and IL-10. In summary, specific microbial taxa involved in maintaining proper brain and immune function are lower in offspring born to mothers with anxiety, depression, or stress, providing strong evidence for a mechanism by which maternal factors may affect offspring health through microbiota dysregulation.

The extracellular DNA lattice of bacterial biofilms is structurally related to Holliday junction recombination intermediates.

Extracellular DNA (eDNA) is a critical component of the extracellular matrix of bacterial biofilms that protects the resident bacteria from environmental hazards, which includes imparting significantly greater resistance to antibiotics and host immune effectors. eDNA is organized into a lattice-like structure, stabilized by the DNABII family of proteins, known to have high affinity and specificity for Holliday junctions (HJs). Accordingly, we demonstrated that the branched eDNA structures present within the biofilms formed by NTHI in the middle ear of the chinchilla in an experimental otitis media model, and in sputum samples recovered from cystic fibrosis patients that contain multiple mixed bacterial species, possess an HJ-like configuration. Next, we showed that the prototypic Escherichia coli HJ-specific DNA-binding protein RuvA could be functionally exchanged for DNABII proteins in the stabilization of biofilms formed by 3 diverse human pathogens, uropathogenic E. coli, nontypeable Haemophilus influenzae, and Staphylococcus epidermidis Importantly, while replacement of DNABII proteins within the NTHI biofilm matrix with RuvA was shown to retain similar mechanical properties when compared to the control NTHI biofilm structure, we also demonstrated that biofilm eDNA matrices stabilized by RuvA could be subsequently undermined upon addition of the HJ resolvase complex, RuvABC, which resulted in significant biofilm disruption. Collectively, our data suggested that nature has recapitulated a functional equivalent of the HJ recombination intermediate to maintain the structural integrity of bacterial biofilms.

The dental plaque biofilm matrix.

The extracellular matrix is a critical component of microbial biofilms, such as dental plaque, maintaining the spatial arrangement of cells and coordinating cellular functions throughout the structure. The extracellular polymeric substances that comprise the matrix include carbohydrates, nucleic acids, proteins, and lipids, which are frequently organized into macromolecular complexes and/or are associated with the surfaces of microbial cells within the biofilm. Cariogenic dental plaque is rich in glucan and fructan polysaccharides derived from extracellular microbial metabolism of dietary sucrose. By contrast, the matrix of subgingival dental plaque is a complex mixture of macromolecules that is still not well understood. Components of the matrix escape from microbial cells during lysis by active secretion or through the shedding of vesicles and serve to anchor microbial cells to the tooth surface. By maintaining the biofilm in close association with host tissues, the matrix facilitates interactions between microorganisms and the host. The outcome of these interactions may be the maintenance of health or the development of dental disease, such as caries or periodontitis. The matrix affords microbial cells protection against chemical and physical insults and hinders the eradication of pathogenic dental plaque. Therefore, strategies to control the matrix are critical to maintain oral health. This review discusses recent advances in our understanding of the composition, origins, and function of the dental plaque matrix, with a focus on subgingival dental plaque. New strategies to control subgingival dental plaque based on targeting the biofilm matrix are also considered.

Polyethylene Glycol 3350 Changes Stool Consistency and the Microbiome but not Behavior of CD1 Mice.

OBJECTIVES: Polyethylene Glycol 3350 (PEG3350) is a laxative commonly used to treat constipation in children. The Food and Drug Administration has received reports of increased anxiety, aggression, and obsessive--compulsive behaviors in children administered PEG3350. Thus, we assessed whether daily administration of PEG3350 leads to anxiety-like behavior in mice. METHODS: Outbred CD-1 IGS mice were administered either a high or a low dose of PEG3350 via daily oral gavage for 2 weeks. As a laxative comparison and control, additional mice were given a high or low dose of magnesium citrate or vehicle (water). Weight and stool consistency were assessed after each gavage to determine laxative effectiveness. Anxiety-like behaviors were assessed using light/dark, open field, and elevated plus maze (EPM) tests at baseline, after 2 weeks of daily gavage, and after a 2 week washout in experiment 1, and after 2 weeks of daily gavage in experiment 2. Stool samples were collected for microbiome analysis in experiment 2 at baseline, after 2 weeks of daily gavage, and after 2 weeks washout. RESULTS: PEG3350 and magnesium citrate significantly changed stool consistency, as well as microbiome alpha and beta diversity. Anxiety-like behaviors were not, however, different in mice administered low or high doses of PEG3350 or magnesium citrate. CONCLUSIONS: Although changes in stool consistency and the gut microbiome occurred, administration of PEG3350 did not alter anxiety-like behaviors.

Predictive model of multiple emergency department visits among adults: analysis of the data from the National Survey of Drug Use and Health (NSDUH).

BACKGROUND: In this methodological paper, we use a novel, predictive approach to examine how demographics, substance use, mental and other health indicators predict multiple visits (≥3) to emergency departments (ED) within a year. METHODS: State-of-the-art predictive methods were used to evaluate predictive ability and factors predicting multiple visits to ED within a year and to identify factors that influenced the strength of the prediction. The analysis used public-use datasets from the 2015-2018 National Surveys on Drug Use and Health (NSDUH), which used the same questionnaire on the variables of interest. Analysis focused on adults aged ≥18 years. Several predictive models (regressions, trees, and random forests) were validated and compared on independent datasets. RESULTS: Predictive ability on a test set for multiple ED visits (≥3 times within a year) measured as the area under the receiver operating characteristic (ROC) reached 0.8, which is good for a national survey. Models revealed consistency in predictive factors across the 4 survey years. The most influential variables for predicting ≥3 ED visits per year were fair/poor self-rated health, being nervous or restless/fidgety, having a lower income, asthma, heart condition/disease, having chronic obstructive pulmonary disease (COPD), nicotine dependence, African-American race, female sex, having diabetes, and being of younger age (18-20). CONCLUSIONS: The findings reveal the need to address behavioral and mental health contributors to ED visits and reinforce the importance of developing integrated care models in primary care settings to improve mental health for medically vulnerable patients. The presented modeling approach can be broadly applied to national and other large surveys.

An enhanced Lactobacillus reuteri biofilm formulation that increases protection against experimental necrotizing enterocolitis.

One significant drawback of current probiotic therapy for the prevention of necrotizing enterocolitis (NEC) is the need for at least daily administration because of poor probiotic persistence after enteral administration, increasing the risk of the probiotic bacteria causing bacteremia or sepsis if the intestines are already compromised. We previously showed that the effectiveness of Lactobacillus reuteri ( Lr) in preventing NEC is enhanced when Lr is grown as a biofilm on the surface of dextranomer microspheres (DM). Here we sought to test the efficacy of Lr administration by manipulating the Lr biofilm state with the addition of biofilm-promoting substances (sucrose and maltose) to DM or by mutating the Lr gtfW gene (encoding an enzyme central to biofilm production). Using an animal model of NEC, we determined that Lr adhered to sucrose- or maltose-loaded DM significantly reduced histologic injury, improved host survival, decreased intestinal permeability, reduced intestinal inflammation, and altered the gut microbiome compared with Lr adhered to unloaded DM. These effects were abolished when DM or GtfW were absent from the Lr inoculum. This demonstrates that a single dose of Lr in its biofilm state decreases NEC incidence. Importantly, preloading DM with sucrose or maltose further enhances Lr protection against NEC in a GtfW-dependent fashion, demonstrating the tunability of the approach and the potential to use other cargos to enhance future probiotic formulations. NEW & NOTEWORTHY Previous clinical trials of probiotics to prevent necrotizing enterocolitis have had variable results. In these studies, probiotics were delivered in their planktonic, free-living form. We have developed a novel probiotic delivery system in which Lactobacillus reuteri (Lr) is delivered in its biofilm state. In a model of experimental necrotizing enterocolitis, this formulation significantly reduces intestinal inflammation and permeability, improves survival, and preserves the natural gut microflora compared with the administration of Lr in its free-living form.

Prevalence of serious psychological distress and mental health treatment in a national sample of pregnant and postpartum women.

This study examines the prevalence and correlates of past month serious psychological distress (SPD) and past year mental health treatment (MHT) across pregnancy and the postpartum. Data are from the 2008 to 2012 National Surveys on Drug Use and Health. Prevalence estimates of SPD as well as MHT among women with SPD were generated for each trimester and across the postpartum period. Correlates of SPD and MHT were examined among pregnant and postpartum women. The prevalence of past month SPD was 6.4 % in first trimester women and 3.9 % in third trimester women. In postpartum women, SPD prevalence ranged from 4.6 % (0-2 months) to 6.9 % (3-5 months). Correlates of SPD among pregnant and postpartum women included being younger; non-Hispanic black; unmarried; making under $20,000 annually; having past month cigarette use; or having a past year alcohol or illicit drug use disorder. Only 38.5 % of pregnant and 49.5 % of postpartum women with past month SPD reported past year MHT. Those who received MHT were more likely to be white; widowed, divorced, or separated; have insurance; and have a history of depression or anxiety than their counterparts with no MHT. Pregnant women with SPD were less likely to report past year MHT than postpartum women, even after adjusting for potential confounders. Over half of pregnant and postpartum women with past month SPD are not receiving MHT. Increased contact with health care professionals during this time may be an opportunity for screening, identification, and referral to MHT.

Streptococcus pyogenes biofilm growth in vitro and in vivo and its role in colonization, virulence, and genetic exchange.

BACKGROUND: Group A streptococcus (GAS) commonly colonizes the oropharynx and nonintact skin. However, colonization has been little studied and the role of biofilm formation is unclear, as biofilm experiments to date have not been conducted under conditions that mimic the host environment. METHODS: In this study we grew GAS biofilms on human keratinocytes under various environmental conditions and used this model to evaluate colonization, invasive disease and natural transformation. RESULTS: GAS grown on epithelial cells, but not biofilms grown on abiotic surfaces, produced biofilms with characteristics similar to in vivo colonization. These biofilm bacteria showed a 100-fold higher bacterial burden of nasal-associated lymphoid tissue in mice than broth-grown bacteria, and were not virulent during septic infection, which was attributed in part to down-regulation of genes typically involved in localized and invasive disease. We also showed for the first time that GAS were naturally transformable when grown in biofilms and during colonization of NALT in vivo. CONCLUSIONS: These findings provide novel model systems to study biofilm formation of GAS in vitro and in vivo, suggest an important role for biofilm formation during GAS colonization, and provide an explanation for the known genome diversity within the GAS population.

Comparison of 2 transvaginal surgical approaches and perioperative behavioral therapy for apical vaginal prolapse: the OPTIMAL randomized trial.

IMPORTANCE: More than 300,000 surgeries are performed annually in the United States for pelvic organ prolapse. Sacrospinous ligament fixation (SSLF) and uterosacral ligament suspension (ULS) are commonly performed transvaginal surgeries to correct apical prolapse. Little is known about their comparative efficacy and safety, and it is unknown whether perioperative behavioral therapy with pelvic floor muscle training (BPMT) improves outcomes of prolapse surgery. OBJECTIVE: To compare outcomes between (1) SSLF and ULS and (2) perioperative BPMT and usual care in women undergoing surgery for vaginal prolapse and stress urinary incontinence. DESIGN, SETTING, AND PARTICIPANTS: Multicenter, 2 × 2 factorial, randomized trial of 374 women undergoing surgery to treat both apical vaginal prolapse and stress urinary incontinence was conducted between 2008 and 2013 at 9 US medical centers. Two-year follow-up rate was 84.5%. INTERVENTIONS: The surgical intervention was transvaginal surgery including midurethral sling with randomization to SSLF (n = 186) or ULS (n = 188); the behavioral intervention was randomization to receive perioperative BPMT (n = 186) or usual care (n = 188). MAIN OUTCOMES AND MEASURES: The primary outcome for the surgical intervention (surgical success) was defined as (1) no apical descent greater than one-third into vaginal canal or anterior or posterior vaginal wall beyond the hymen (anatomic success), (2) no bothersome vaginal bulge symptoms, and (3) no re-treatment for prolapse at 2 years. For the behavioral intervention, primary outcome at 6 months was urinary symptom scores (Urinary Distress Inventory; range 0-300, higher scores worse), and primary outcomes at 2 years were prolapse symptom scores (Pelvic Organ Prolapse Distress Inventory; range 0-300, higher scores worse) and anatomic success. RESULTS: At 2 years, surgical group was not significantly associated with surgical success rates (ULS, 59.2% [93/157] vs SSLF, 60.5% [92/152]; unadjusted difference, -1.3%; 95% CI, -12.2% to 9.6%; adjusted odds ratio [OR], 0.9; 95% CI, 0.6 to 1.5) or serious adverse event rates (ULS, 16.5% [31/188] vs SSLF, 16.7% [31/186]; unadjusted difference, -0.2%; 95% CI, -7.7% to 7.4%; adjusted OR, 0.9; 95% CI, 0.5 to 1.6). Perioperative BPMT was not associated with greater improvements in urinary scores at 6 months (adjusted treatment difference, -6.7; 95% CI, -19.7 to 6.2), prolapse scores at 24 months (adjusted treatment difference, -8.0; 95% CI, -22.1 to 6.1), or anatomic success at 24 months. CONCLUSIONS AND RELEVANCE: Two years after vaginal surgery for prolapse and stress urinary incontinence, neither ULS nor SSLF was significantly superior to the other for anatomic, functional, or adverse event outcomes. Perioperative BPMT did not improve urinary symptoms at 6 months or prolapse outcomes at 2 years. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT00597935.

Stress and depression-associated shifts in gut microbiota: A pilot study of human pregnancy.

Background: Psychosocial stress and mood-related disorders, such as depression, are prevalent and vulnerability to these conditions is heightened during pregnancy. Psychosocial stress induces consequences via several mechanisms including the gut microbiota-brain axis and associated signaling pathways. Previous preclinical work indicates that prenatal stress alters maternal gut microbial composition and impairs offspring development. Importantly, although the fecal and vaginal microenvironments undergo alterations across pregnancy, we lack consensus regarding which shifts are adaptive or maladaptive in the presence of prenatal stress and depression. Clinical studies interrogating these relationships have identified unique taxa but have been limited in study design. Methods: We conducted a prospective cohort study of pregnant individuals consisting of repeated administration of psychometrics (Perceived Stress Scale (PSS) and Center for Epidemiological Studies Depression Scale (CES-D)) and collection of fecal and vaginal microbiome samples. Fecal and vaginal microbial community composition across psychometric responses were interrogated using full-length 16S rRNA sequencing followed by α and ß-diversity metrics and taxonomic abundance. Results: Early pregnancy stress was associated with increased abundance of fecal taxa not previously identified in related studies, and stress from late pregnancy through postpartum was associated with increased abundance of typical vaginal taxa and opportunistic pathogens in the fecal microenvironment. Additionally, in late pregnancy, maternal stress and depression scores were associated with each other and with elevated maternal C-C motif chemokine ligand 2 (CCL2) concentrations. At delivery, concordant with previous literature, umbilical CCL2 concentration was negatively correlated with relative abundance of maternal fecal Lactobacilli. Lastly, participants with more severe depressive symptoms experienced steeper decreases in prenatal vaginal α-diversity. Conclusion: These findings a) underscore previous preclinical and clinical research demonstrating the effects of prenatal stress on maternal microbiome composition, b) suggest distinct biological pathways for the consequences of stress versus depression and c) extend the literature by identifying several taxa which may serve critical roles in mediating this relationship. Thus, further interrogation of the role of specific maternal microbial taxa in relation to psychosocial stress and its sequelae is warranted.

Long-term outcomes following abdominal sacrocolpopexy for pelvic organ prolapse.

IMPORTANCE: More than 225 000 surgeries are performed annually in the United States for pelvic organ prolapse (POP). Abdominal sacrocolpopexy is considered the most durable POP surgery, but little is known about safety and long-term effectiveness. OBJECTIVES: To describe anatomic and symptomatic outcomes up to 7 years after abdominal sacrocolpopexy, and to determine whether these are affected by concomitant anti-incontinence surgery (Burch urethropexy). DESIGN, SETTING, AND PARTICIPANTS: Long-term follow-up of the randomized, masked 2-year Colpopexy and Urinary Reduction Efforts (CARE) trial of women with stress continence who underwent abdominal sacrocolpopexy between 2002 and 2005 for symptomatic POP and also received either concomitant Burch urethropexy or no urethropexy. Ninety-two percent (215/233) of eligible 2-year CARE trial completers were enrolled in the extended CARE study; and 181 (84%) and 126 (59%) completed 5 and 7 years of follow-up, respectively. The median follow-up was 7 years. MAIN OUTCOMES AND MEASURES: Symptomatic POP failure requiring retreatment or self-reported bulge; or anatomic POP failure requiring retreatment or Pelvic Organ Prolapse Quantification evaluation demonstrating descent of the vaginal apex below the upper third of the vagina, or anterior or posterior vaginal wall prolapse beyond the hymen. Stress urinary incontinence (SUI) with more than 1 symptom or interval treatment; or overall UI score of 3 or greater on the Incontinence Severity Index. RESULTS: By year 7, the estimated probabilities of treatment failure (POP, SUI, UI) from parametric survival modeling for the urethropexy group and the no urethropexy group, respectively, were 0.27 and 0.22 for anatomic POP (treatment difference of 0.050; 95% CI, -0.161 to 0.271), 0.29 and 0.24 for symptomatic POP (treatment difference of 0.049; 95% CI, -0.060 to 0.162), 0.48 and 0.34 for composite POP (treatment difference of 0.134; 95% CI, -0.096 to 0.322), 0.62 and 0.77 for SUI (treatment difference of -0.153; 95% CI, -0.268 to 0.030), and 0.75 and 0.81 for overall UI (treatment difference of -0.064; 95% CI, -0.161 to 0.032). Mesh erosion probability at 7 years (estimated by the Kaplan-Meier method) was 10.5% (95% CI, 6.8% to 16.1%). CONCLUSIONS AND RELEVANCE: During 7 years of follow-up, abdominal sacrocolpopexy failure rates increased in both groups. Urethropexy prevented SUI longer than no urethropexy. Abdominal sacrocolpopexy effectiveness should be balanced with long-term risks of mesh or suture erosion. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT00099372.

Trends in Opioid Misuse Among Individuals Aged 12 to 21 Years in the US.

Importance: Although opioid misuse has been decreasing among US youths and adolescents in recent years, it is unclear what has contributed to this trend and how this trend differs by age group and sex over time. Objective: To identify trends in opioid misuse among youths and young adults across and between ages, birth cohorts, and sexes. Design, Setting, and Participants: Cross-sectional National Survey on Drug Use and Health (NSDUH) public-use files were used to produce nationally representative pseudocohorts. The survey population includes the civilian US population in the 50 states and Washington, DC. Individuals without a fixed address and institutionalized individuals were excluded. Respondents to the NSDUH are a population-based sample selected using a stratified cluster design. For the years (January 1, 2002, to December 31, 2019) and ages (12-21 years) analyzed, the sample sizes ranged from 1607 to 3239 respondents. Data were analyzed from January 1, 2022, to April 12, 2023, for the main outcome by age, sex, and pseudocohort. Main Outcomes and Measures: Respondents were asked whether they misused prescription opioids or used heroin in the past year. The analysis hypotheses were formulated and tested after data collection. Results: In a total of 5 pseudocohorts, data from 114 412 respondents aged 12 to 21 years were analyzed; the unweighted distribution of male sex (complement was female) ranged from 47.7% to 52.6% (mean [SD], 50.6% [1.1%]). Response rates ranged from 45.8% to 71.3%. High school-aged youths and young adults had distinctly lower rates of opioid misuse in later pseudocohorts compared with earlier ones. Rates of misuse among individuals aged 16 years were 2.80% (95% CI, 1.06%-4.54%) higher in 2002 vs 2008; among those aged 18 years, rates were 4.36% (95% CI, 1.85%-6.87%) higher in 2002. Similarly, rates of misuse among individuals aged 16 years were 3.93% (95% CI, 2.15%-5.71%) higher in 2008 vs 2014; among those aged 17 years, rates were 3.41% (95% CI, 1.94%-4.88%) higher in 2008. Similar patterns were observed by sex. In earlier cohorts, younger female participants had higher rates of opioid misuse than their male counterparts and older male participants had higher rates than their female counterparts. Sex differences decreased in later cohorts. Conclusions and Results: The findings of this cross-sectional study of US youths and young adults suggest that high school-aged individuals consistently misused fewer opioids in later pseudocohorts overall and by sex. Sex differences in opioid rates also diminished in later pseudocohorts. A decrease in drug availability and general exposure to the harms of opioid use could be contributing to these findings. Future planned research using this pseudocohort approach will examine polysubstance use and evaluate how substance use differs by other sociodemographic characteristics.

The cryptic competence pathway in Streptococcus pyogenes is controlled by a peptide pheromone.

Horizontal gene transfer is an important means of bacterial evolution that is facilitated by transduction, conjugation, and natural genetic transformation. Transformation occurs after bacterial cells enter a state of competence, where naked DNA is acquired from the extracellular environment. Induction of the competent state relies on signals that activate master regulators, causing the expression of genes involved in DNA uptake, processing, and recombination. All streptococcal species contain the master regulator SigX and SigX-dependent effector genes required for natural genetic transformation; however, not all streptococcal species have been shown to be naturally competent. We recently demonstrated that competence development in Streptococcus mutans requires the type II ComRS quorum-sensing circuit, comprising an Rgg transcriptional activator and a novel peptide pheromone (L. Mashburn-Warren, D. A. Morrison, and M. J. Federle, Mol. Microbiol. 78:589-606, 2010). The type II ComRS system is shared by the pyogenic, mutans, and bovis streptococci, including the clinically relevant pathogen Streptococcus pyogenes. Here, we describe the activation of sigX by a small-peptide pheromone and an Rgg regulator of the type II ComRS class. We confirm previous reports that SigX is functional and able to activate sigX-dependent gene expression within the competence regulon, and that SigX stability is influenced by the cytoplasmic protease ClpP. Genomic analyses of available S. pyogenes genomes revealed the presence of intact genes within the competence regulon. While this is the first report to show natural induction of sigX, S. pyogenes remained nontransformable under laboratory conditions. Using radiolabeled DNA, we demonstrate that transformation is blocked at the stage of DNA uptake.

Development of competence for genetic transformation of Streptococcus mutans in a chemically defined medium.

Streptococcus mutans develops competence for genetic transformation in response to regulatory circuits that sense at least two peptide pheromones. One peptide, known as CSP, is sensed by a two-component signal transduction system through a membrane receptor, ComD. The other, derived from the primary translation product ComS, is thought to be sensed by an intracellular receptor, ComR, after uptake by oligopeptide permease. To allow study of this process in a medium that does not itself contain peptides, development of competence was examined in the chemically defined medium (CDM) described by van de Rijn and Kessler (Infect. Immun. 27:444, 1980). We confirmed a previous report that in this medium comS mutants of strain UA159 respond to a synthetic peptide comprising the seven C-terminal residues of ComS (ComS(11-17)) by increasing expression of the alternative sigma factor SigX, which in turn allows expression of competence effector genes. This response provided the basis for a bioassay for the ComS pheromone in the 100 to 1,000 nM range. It was further observed that comS(+) (but not comS mutant) cultures developed a high level of competence in the late log and transition phases of growth in this CDM without the introduction of any synthetic stimulatory peptide. This endogenous competence development was accompanied by extracellular release of one or more signals that complemented a comS mutation at levels equivalent to 1 µM synthetic ComS(11-17).

National polydrug use patterns among people who misuse prescription opioids and people who use heroin. Results from the National Household Survey on Drug Use and Health.

BACKGROUND: Polysubstance use among people who misuse opioids (PWMO) is highly prevalent, but understudied. We defined, estimated, and analyzed national polysubstance use patterns among PWMO using National Household Survey on Drug Use and Health data (2017-2019). METHODS: We obtained estimates of past-month patterns of polydrug use using cluster analysis and latent class/profile analysis. We considered misuse of prescription opioids and use of heroin, cocaine (including crack), marijuana, alcohol, and "other" substances. RESULTS: We identified a five-cluster solution for binary indicators of past-month use and a six-cluster solution for frequency of use. The largest binary cluster (37%) included misuse of prescription opioids and use of alcohol. The second-largest cluster (15%) included misuse of prescription opioids, alcohol, marijuana, and "other" substances. Among those who used heroin, 36% used methamphetamine. In terms of frequency of use, the largest cluster among people who misuse opioid who used multiple substances (almost 40%) misused prescription pain relievers, alcohol, and marijuana infrequently. The second-largest cluster (23%) used marijuana almost daily and misused prescription pain relievers an average of 6.6 days. PWMO in a cluster of almost daily heroin use indicated use of methamphetamine, marijuana, and prescription opioids. Those who used methamphetamine, were using it more than 15 days a month. CONCLUSIONS: We have developed reference measures of polydrug patterns among US household population and estimated their demographic characteristics. We identified clusters of high-risk polydrug use. These findings have implications for the development of prevention and treatment solutions in the United States.

CRITICAL WINDOW VARIABLE SELECTION FOR MIXTURES: ESTIMATING THE IMPACT OF MULTIPLE AIR POLLUTANTS ON STILLBIRTH.

Understanding the role of time-varying pollution mixtures on human health is critical as people are simultaneously exposed to multiple pollutants during their lives. For vulnerable subpopulations who have well-defined exposure periods (e.g., pregnant women), questions regarding critical windows of exposure to these mixtures are important for mitigating harm. We extend critical window variable selection (CWVS) to the multipollutant setting by introducing CWVS for mixtures (CWVSmix), a hierarchical Bayesian method that combines smoothed variable selection and temporally correlated weight parameters to: (i) identify critical windows of exposure to mixtures of time-varying pollutants, (ii) estimate the time-varying relative importance of each individual pollutant and their first order interactions within the mixture, and (iii) quantify the impact of the mixtures on health. Through simulation we show that CWVSmix offers the best balance of performance in each of these categories in comparison to competing methods. Using these approaches, we investigate the impact of exposure to multiple ambient air pollutants on the risk of stillbirth in New Jersey, 2005-2014. We find consistent elevated risk in gestational weeks 2, 16-17, and 20 for non-Hispanic Black mothers, with pollution mixtures dominated by ammonium (weeks 2, 17, 20), nitrate (weeks 2, 17), nitrogen oxides (weeks 2, 16), PM2.5 (week 2), and sulfate (week 20). The method is available in the R package CWVSmix.

Antibacterial and anti-inflammatory effects of Lactobacillus reuteri in its biofilm state contribute to its beneficial effects in a rat model of experimental necrotizing enterocolitis.

INTRODUCTION: Necrotizing enterocolitis (NEC) remains a significant surgical emergency in neonates. We have demonstrated the efficacy of Lactobacillus reuteri (Lr) in protecting against experimental NEC when administered as a biofilm by incubation with maltose loaded dextranomer microspheres. Lr possesses antimicrobial and anti-inflammatory properties. We developed mutant strains of Lr to examine the importance of its antimicrobial and anti-inflammatory properties in protecting the intestines from NEC. METHODS: Premature rat pups were exposed to hypoxia/hypothermia/hypertonic feeds to induce NEC. To examine the importance of antimicrobial reuterin and anti-inflammatory histamine, pups received either native or mutant forms of Lr, in either its planktonic or biofilm states, prior to induction of NEC. Intestinal histology was examined upon sacrifice. RESULTS: Compared to no treatment, administration of a single dose of Lr in its biofilm state significantly decreased the incidence of NEC (67% vs. 18%, p < 0.0001), whereas Lr in its planktonic state had no significant effect. Administration of reuterin-deficient or histamine-deficient forms of Lr, in either planktonic or biofilm states, resulted in significant loss of efficacy. CONCLUSION: Antimicrobial and anti-inflammatory effects of Lr contribute to its beneficial effects against NEC. This suggests that both infectious and inflammatory components contribute to the etiology of NEC.

A novel double-tryptophan peptide pheromone controls competence in Streptococcus spp. via an Rgg regulator.

All streptococcal genomes encode the alternative sigma factor SigX and 21 SigX-dependent proteins required for genetic transformation, yet no pyogenic streptococci are known to develop competence. Resolving this paradox may depend on understanding the regulation of sigX. We report the identification of a regulatory circuit linked to the sigX genes of mutans, pyogenic, and bovis streptococci that uses a novel small, double-tryptophan-containing sigX-inducing peptide (XIP) pheromone. In all three groups, the XIP gene (comS), and sigX have identical, non-canonical promoters consisting of 9 bp inverted repeats separated from a -10 hexamer by 19 bp. comS is adjacent to a gene encoding a putative transcription factor of the Rgg family and is regulated by its product, which we designate ComR. Deletion of comR or comS in Streptococcus mutans abolished transformability, as did deletion of the oligopeptide permease subunit oppD, suggesting that XIP is imported. Providing S. mutans with synthetic fragments of ComS revealed that seven C-terminal residues, including the WW motif, cause robust induction of both sigX and the competent state. We propose that this circuit is the proximal regulator of sigX in S. mutans, and we infer that it controls competence in a parallel way in all pyogenic and bovis streptococci.

Factor structure of the National Alzheimer's Coordinating Centers uniform dataset neuropsychological battery: an evaluation of invariance between and within groups over time.

The neuropsychological battery from the National Alzheimer's Disease Coordinating Center is designed to provide a sensitive assessment of mild cognitive disorders for multicenter investigations. Comprising 8 common neuropsychological tests (12 measures), the battery assesses cognitive domains affected early in the course of Alzheimer disease. We examined the factor structure of the battery across levels of cognition [normal, mild cognitive impairment, dementia] based on Clinical Dementia Rating scores to determine cognitive domains tapped by the battery. Using data pooled from 29 Alzheimer's Disease Centers funded by National Institute on Aging, exploratory factor analysis was used to derive a general model using half of the sample; 4 factors representing memory, attention, executive function, and language were identified. Confirmatory factor analysis was used on the second half of the sample to evaluate invariance between groups and within groups over 1 year. Factorial invariance testing included systematic addition of constraints and comparisons of nested models. The general confirmatory factor analysis model had a good fit. As constraints were added, model fit deteriorated slightly. Comparisons within groups showed stability over 1 year. In a range of cognition from normal to dementia, factor structures and factor loadings will vary little. Further work is needed to determine whether domains become more or less distinct in severely cognitively compromised individuals.