Host inflammatory dynamics reveal placental immune modulation by Group B Streptococcus during pregnancy.

Group B Streptococcus (GBS) is a pathobiont that can ascend to the placenta and cause adverse pregnancy outcomes, in part through production of the toxin ß-hemolysin/cytolysin (ß-h/c). Innate immune cells have been implicated in the response to GBS infection, but the impact of ß-h/c on their response is poorly defined. We show that GBS modulates innate immune cell states by subversion of host inflammation through ß-h/c, allowing worse outcomes. We used an ascending mouse model of GBS infection to measure placental cell state changes over time following infection with a ß-h/c-deficient and isogenic wild type GBS strain. Transcriptomic analysis suggests that ß-h/c-producing GBS elicit a worse phenotype through suppression of host inflammatory signaling in placental macrophages and neutrophils, and comparison of human placental macrophages infected with the same strains recapitulates these results. Our findings have implications for identification of new targets in GBS disease to support host defense against pathogenic challenge.

Using What We Already Have: Uncovering New Drug Repurposing Strategies in Existing Omics Data.

The promise of drug repurposing is to accelerate the translation of knowledge to treatment of human disease, bypassing common challenges associated with drug development to be more time- and cost-efficient. Repurposing has an increased chance of success due to the previous validation of drug safety and allows for the incorporation of omics. Hypothesis-generating omics processes inform drug repurposing decision-making methods on drug efficacy and toxicity. This review summarizes drug repurposing strategies and methodologies in the context of the following omics fields: genomics, epigenomics, transcriptomics, proteomics, metabolomics, microbiomics, phenomics, pregomics, and personomics. While each omics field has specific strengths and limitations, incorporating omics into the drug repurposing landscape is integral to its success.

Impact of Metabolic Stress on BeWo Syncytiotrophoblast Function.

During placental formation, cytotrophoblasts (CTBs) fuse into multinucleate, microvilli-coated syncytiotrophoblasts (STBs), which contact maternal blood, mediating nutrient, metabolite, and gas exchange between mother and fetus, and providing a barrier against fetal infection. Trophoblasts remodel the surrounding extracellular matrix through the secretion of matrix metalloproteinases (MMPs). Maternal obesity and diabetes mellitus can negatively impact fetal development and may impair trophoblast function. We sought to model the impact of metabolic stress on STB function by examining MMP and hormone secretion. The BeWo CTB cell line was syncytialized to STB-like cells with forskolin. Cell morphology was examined by electron microscopy and immunofluorescence; phenotype was further assessed by ELISA and RT-qPCR. STBs were exposed to a metabolic stress cocktail (MetaC: 30 mM glucose, 10 nM insulin, and 0.1 mM palmitic acid). BeWo syncytialization was demonstrated by increased secretion of HCGß and progesterone, elevated syncytin gene expression (ERVW-1 and ERVFRD-1), loss of tight junctions, and increased surface microvilli. MetaC strongly suppressed syncytin gene expression (ERVW-1 and ERVFRD-1), suppressed HCGß and progesterone secretion, and altered both MMP-9 and MMP-2 production. Metabolic stress modeling diabetes and obesity altered BeWo STB hormone and MMP production in vitro.

The impact of HIV and ART exposure during pregnancy on fetal growth: a prospective study in a South African cohort.

BACKGROUND: In utero exposure to human immunodeficiency virus (HIV) and antiretroviral (ART) is associated with adverse birth outcomes, which are often attributed to alterations in placental morphology. This study used structural equation models (SEMs) to examine the impact of HIV and ART exposure on fetal growth outcomes and whether these associations are mediated by placental morphology in urban-dwelling Black South African women. METHODS: This prospective cohort study included pregnant women living with HIV (WLWH, n = 122) and not living with HIV (WNLWH, n = 250) that underwent repeated ultrasonography during pregnancy, and at delivery, to determine fetal growth parameters in Soweto, South Africa. The size and the velocity of fetal growth measures (i.e., head and abdominal circumference, biparietal diameter, and femur length) were calculated using the Superimposition by Translation and Rotation. Placenta digital photographs taken at delivery were used to estimate morphometric parameters and trimmed placental weight was measured. All WLWH were receiving ART for the prevention of vertical transmission of HIV. RESULTS: A trend towards a lower placental weight and significantly shorter umbilical cord length was reported in WLWH compared to their counterparts. After sex stratification, umbilical cord length was significantly shorter in males born to WLWH than in male fetuses born to WNLWH (27.3 (21.6-32.8) vs. 31.4 (25.0-37.0) cm, p = 0.015). In contrast, female fetuses born to WLWH had lower placental weight, birth weight (2.9 (2.3-3.1) vs. 3.0 (2.7-3.2) kg), and head circumference (33 (32-34) vs. 34 (33-35) cm) than their counterparts (all p ≤ 0.05). The SEM models showed an inverse association between HIV and head circumference size and velocity in female fetuses. In contrast, HIV and ART exposure was positively associated with femur length growth (both size and velocity) and abdominal circumference velocity in male fetuses. None of these associations appeared to be mediated via placental morphology. CONCLUSION: Our findings suggest that HIV and ART exposure directly affects head circumference growth in females and abdominal circumference velocity in male fetuses; but may improve femur length growth in male fetuses only.

Walk before you run: Feasibility challenges and lessons learned from the PROCLAIM study, a multicenter randomized controlled trial of misoprostol for prevention of recurrent Clostridioides difficile during COVID-19.

We analyzed our challenging experience with a randomized controlled trial of misoprostol for prevention of recurrent C. difficile. Despite careful prescreening and thoughtful protocol modifications to facilitate enrollment, we closed the study early after enrolling just 7 participants over 3 years. We share lessons learned, noting the importance of feasibility studies, inclusion of biomarker outcomes, and dissemination of such findings to inform future research design and implementation successes.

Contraceptive exposure associates with urinary tract infection risk in a cohort of reproductive-age women: a case control study.

PURPOSE: Although non-barrier contraception is commonly prescribed, the risk of urinary tract infections (UTI) with contraceptive exposure is unclear. MATERIALS AND METHODS: Using data from Vanderbilt University Medical Centre's deidentified electronic health record (EHR), women ages 18-52 were randomly sampled and matched based on age and length of EHR. This case-control analysis tested for association between contraception exposure and outcome using UTI-positive (UTI+) as cases and upper respiratory infection+ (URI+) as controls. RESULTS: 24,563 UTI + cases (mean EHR: 64.2 months; mean age: 31.2 years) and 48,649 UTI-/URI + controls (mean EHR: 63.2 months; mean age: 31.9 years) were analysed. In the primary analysis, UTI risk was statistically significantly increased for the oral contraceptive pill (OCP; OR = 1.10 [95%CI = 1.02-1.11], p ≤ 0.05), intrauterine device (IUD; OR = 1.13 [95%CI = 1.04-1.23], p ≤ 0.05), etonogestrel implant (Nexplanon®; OR = 1.56 [95% CI = 1.24-1.96], p ≤ 0.05), and medroxyprogesterone acetate injectable (Depo-Provera®; OR = 2.16 [95%CI = 1.99-2.33], p ≤ 0.05) use compared to women not prescribed contraception. A secondary analysis that included any non-IUD contraception, which could serve as a proxy for sexual activity, demonstrated a small attenuation for the association between UTI and IUD (OR = 1.09 [95%CI = 0.98-1.21], p = 0.13). CONCLUSION: This study notes potential for a small increase in UTIs with contraceptive use. Prospective studies are required before this information is applied in clinical settings. CONDENSATION: Although non-barrier contraception is commonly prescribed, the risk of urinary tract infections (UTI) with contraceptive exposure is poorly understood. This large-cohort, case-control study notes potential for a small increase in UTIs with contraceptive use.

The antimicrobial activity of zinc against group B Streptococcus is strain-dependent across diverse sequence types, capsular serotypes, and invasive versus colonizing isolates.

BACKGROUND: Streptococcus agalactiae or Group B Streptococcus (GBS) is an encapsulated gram-positive bacterial pathobiont that commonly colonizes the lower gastrointestinal tract and reproductive tract of human hosts. This bacterium can infect the gravid reproductive tract and cause invasive infections of pregnant patients and neonates. Upon colonizing the reproductive tract, the bacterial cell is presented with numerous nutritional challenges imposed by the host. One strategy employed by the host innate immune system is intoxication of bacterial invaders with certain transition metals such as zinc. METHODOLOGY: Previous work has demonstrated that GBS must employ elegant strategies to circumnavigate zinc stress in order to survive in the vertebrate host. We assessed 30 strains of GBS from diverse isolation sources, capsular serotypes, and sequence types for susceptibility or resistance to zinc intoxication. RESULTS: Invasive strains, such as those isolated from early onset disease manifestations of GBS infection were significantly less susceptible to zinc toxicity than colonizing strains isolated from rectovaginal swabs of pregnant patients. Additionally, capsular type III (cpsIII) strains and the ST-17 and ST-19 strains exhibited the greatest resilience to zinc stress, whereas ST-1 and ST-12 strains as well as those possessing capsular type Ib (cpsIb) were more sensitive to zinc intoxication. Thus, this study demonstrates that the transition metal zinc possesses antimicrobial properties against a wide range of GBS strains, with isolation source, capsular serotype, and sequence type contributing to susceptibility or resistance to zinc stress.

Persistent bacteremia and psoas abscess caused by a lethal toxin-deficient Paeniclostridiumsordellii.

We present a case of persistent bacteremia and psoas abscess from Paeniclostridium sordellii without severe symptoms or the classically associated toxic shock syndrome. Further laboratory evaluation demonstrated that the Paeniclostridium sordellii isolate lacked the lethal toxin gene and there was no cytotoxicity to exposed Vero cells.

Distinct Group B Streptococcus Sequence and Capsule Types Differentially Impact Macrophage Stress and Inflammatory Signaling Responses.

Group B Streptococcus (GBS) is an opportunistic bacterial pathogen that can contribute to the induction of preterm birth in colonized pregnant women and to severe neonatal disease. Many questions regarding the mechanisms that drive GBS-associated pathogenesis remain unanswered, and it is not yet clear why virulence has been observed to vary so extensively across GBS strains. Previously, we demonstrated that GBS strains of different sequence types (STs) and capsule (CPS) types induce different cytokine profiles in infected THP-1 macrophage-like cells. Here, we expanded on these studies by utilizing the same set of genetically diverse GBS isolates to assess ST and CPS-specific differences in upstream cell death and inflammatory signaling pathways. Our results demonstrate that particularly virulent STs and CPS types, such as the ST-17 and CPS III groups, induce enhanced Jun-N-terminal protein kinase (JNK) and NF-κB pathway activation following GBS infection of macrophages compared with other ST or CPS groups. Additionally, we found that ST-17, CPS III, and CPS V GBS strains induce the greatest levels of macrophage cell death during infection and exhibit a more pronounced ability to be internalized and to survive in macrophages following phagocytosis. These data provide further support for the hypothesis that variable host innate immune responses to GBS, which significantly impact pathogenesis, stem in part from genotypic and phenotypic differences among GBS isolates. These and similar studies may inform the development of improved diagnostic, preventive, or therapeutic strategies targeting invasive GBS infections.

The Impact of State Mask-Wearing Requirements on the Growth of Coronavirus Disease 2019 Cases, Hospitalizations, and Deaths in the United States.

In ecologic analyses of US states, piecewise multivariable models showed lower case-rate slopes after implementation of mask requirements: -1.0% (95% confidence interval, -1.34% to -.57%) and -0.44% (-.86% to -.03%) per 100 000 per day in early- and late-adopter states, respectively, compared with never-adopter states. Our findings support statewide mask requirements to mitigate transmission of coronavirus disease 2019.

Epidemiological Trends of Racial Differences in Early- and Late-onset Group B Streptococcus Disease in Tennessee.

BACKGROUND: The rates of early-onset group B Streptococcus (GBS) disease (EOGBS) have declined since the implementation of universal screening and intrapartum antibiotic prophylaxis guidelines but late-onset (LOGBS) rates remain unchanged. Racial differences in GBS disease rates have been previously documented, with Black infants having higher rates of EOGBS and LOGBS, but it is not known if these have persisted. Therefore, we sought to determine the differences in EOGBS and LOGBS disease by race over the past decade in Tennessee. METHODS: This study used active population-based and laboratory-based surveillance data for invasive GBS disease conducted through Active Bacterial Core surveillance in selected counties across Tennessee. We included infants younger than 90 days and who had invasive GBS disease between 2009 and 2018. RESULTS: A total of 356 GBS cases were included, with 60% having LOGBS. EOGBS and LOGBS had decreasing temporal trends over the study period. Overall, there were no changes in temporal trend noted in the rates of EOGBS and LOGBS among White infants. However, Black infants had significantly decreasing EOGBS and LOGBS temporal trends (relative risk [95% confidence interval], .87 [.79, .96] [P = .007] and .90 [.84-.97] [P = .003], respectively). CONCLUSIONS: Years after the successful implementation of the universal screening guidelines, our data revealed an overall decrease in LOGBS rates, primarily driven by changes among Black infants. More studies are needed to characterize the racial disparities in GBS rates, and factors driving them. Prevention measures such as vaccination are needed to have a further impact on disease rates.

Antibacterial and Anti-biofilm Activity of the Human Breast Milk Glycoprotein Lactoferrin against Group B Streptococcus.

Group B Streptococcus (GBS) is an encapsulated Gram-positive human pathogen that causes invasive infections in pregnant hosts and neonates, as well as immunocompromised individuals. Colonization of the human host requires the ability to adhere to mucosal surfaces and circumnavigate the nutritional challenges and antimicrobial defenses associated with the innate immune response. Biofilm formation is a critical process to facilitate GBS survival and establishment of a replicative niche in the vertebrate host. Previous work has shown that the host responds to GBS infection by producing the innate antimicrobial glycoprotein lactoferrin, which has been implicated in repressing bacterial growth and biofilm formation. Additionally, lactoferrin is highly abundant in human breast milk and could serve a protective role against invasive microbial pathogens. This study demonstrates that human breast milk lactoferrin has antimicrobial and anti-biofilm activity against GBS and inhibits its adherence to human gestational membranes. Together, these results indicate that human milk lactoferrin could be used as a prebiotic chemotherapeutic strategy to limit the impact of bacterial adherence and biofilm formation on GBS-associated disease outcomes.

The impact of Lactobacillus on group B streptococcal interactions with cells of the extraplacental membranes.

Group B Streptococcus (GBS) causes adverse pregnancy outcomes and neonatal disease. The recommended preventative measure is intrapartum antibiotic prophylaxis, which can prevent early onset neonatal disease but not chorioamnionitis, preterm labor, stillbirth, or late-onset disease. Novel prevention methods are therefore needed. Use of probiotics including Lactobacillus spp., has been suggested given that they are dominant members of the lower reproductive tract microbiome. Although Lactobacillus was shown to reduce recto-vaginal colonization of GBS, no studies have examined how Lactobacillus impacts GBS in the extraplacental membranes. Since Lactobacillus has been detected in the placental membranes, we sought to characterize GBS-Lactobacillus interactions in vitro using a colonizing and invasive GBS strain. While live Lactobacillus did not affect growth or biofilms in GBS, co-culture with L. gasseri led to a 224-fold increase in GBS association with decidualized human endometrial stromal cells for both GBS strains (p < 0.005). Increased association did not result in increased invasion (p > 0.05) or host cell death, though some GBS and Lactobacillus combinations contributed to a significant reduction in host cell death (p < 0.05). Since Lactobacillus secretes many inhibitory compounds, the effect of Lactobacillus supernatants on GBS was also examined. The supernatants inhibited GBS growth, biofilm formation and invasion of host cells, though strain dependent effects were observed. Notably, supernatant from L. reuteri 6475 broadly inhibited growth in 36 distinct GBS strains and inhibited GBS growth to an average of 46.6% of each GBS strain alone. Together, these data show that specific Lactobacillus strains and their secreted products have varying effects on GBS interactions with cells of the extraplacental membranes that could impact pathogenesis. Understanding these interactions could help guide new treatment options aimed at reducing GBS-associated maternal complications and disease.

DECONSTRUCTING EXTRAPLACENTAL MEMBRANES TO UNDERSTAND BACTERIAL CHORIOAMNIONITIS.

Bacterial chorioamnionitis is an intrauterine infection that occurs during pregnancy and involves the membranes that extend from the placenta to form the sac encasing the amniotic fluid and developing fetus. Chorioamnionitis is most commonly caused by bacteria that likely ascend from the vagina into the gravid uterus and can result in devastating complications such as preterm labor, membrane rupture, fetal stillbirth, or severe infection of the newborn. Surviving babies exposed to chorioamnionitis in utero have an increased risk of lifelong disability. Unfortunately, most chorioamnionitis is clinically silent unless a bad outcome occurs, which compels the need for better diagnostic, therapeutic, and preventive approaches. Our lab has a primary interest in defining the early steps in disease pathogenesis of bacterial chorioamnionitis, when microbes first make contact with the fetal membranes. Through team science, we are using organ-on-chip models of human fetal membranes to define host-microbe interactions critical to the development of chorioamnionitis and its complications.

Modulation of Death and Inflammatory Signaling in Decidual Stromal Cells following Exposure to Group B Streptococcus.

Group B Streptococcus (GBS) is an opportunistic bacterial pathogen that contributes to miscarriage, preterm birth, and serious neonatal infections. Studies have indicated that some multilocus sequence types (STs) of GBS are more likely to cause severe disease than others. We hypothesized that the ability of GBS to elicit varying host responses in maternal decidual tissue during pregnancy is an important factor regulating infection and disease severity. To address this hypothesis, we utilized an antibody microarray to compare changes in production and activation of host signaling proteins in decidualized telomerase-immortalized human endometrial stromal cells (dT-HESCs) following infection with GBS strains from septic neonates or colonized mothers. GBS infection increased levels of total and phosphorylated mitogen-activated protein kinase (MAPK) family members such as p38 and JNK and induced nuclear factor kappa B (NF-κB) pathway activation. Infection also altered the regulation of additional proteins that mediate cell death and inflammation in a strain-specific manner, which could be due to the observed variation in attachment to and invasion of the decidual stromal cells and ability to lyse red blood cells. Further analyses confirmed array results and revealed that p38 promotes programmed necrosis in dT-HESCs. Together, the observed signaling changes may contribute to deregulation of critical developmental signaling cascades and inflammatory responses following infection, both of which could trigger GBS-associated pregnancy complications.

Mildred Rebstock: Profile of the Medicinal Chemist Who Synthesized Chloramphenicol.

This year marks the 70th anniversary since Parke-Davis and Company announced the synthesis of chloramphenicol, the first naturally occurring antibiotic to be chemically generated in vitro for large-scale production. The effort was led by the chemist Mildred Rebstock, Ph.D., (1919 to 2011), who would turn 100 years old this year. Her accomplishment, at a time when very few chemists in the United States were women, was celebrated internationally. This commentary reviews her important contribution.

The STAT4/MLL1 Epigenetic Axis Regulates the Antimicrobial Functions of Murine Macrophages.

Macrophages are critical immune cells for the clearance of microbial pathogens and cellular debris from peripheral tissues. Macrophage inflammatory responses are governed by gene expression patterns, and these patterns are often subject to epigenetic control. Chromatin modifications, such as histone methylation, regulate gene accessibility in macrophages, and macrophage polarization is governed in part by the expression and function of chromatin-modifying enzymes. The histone methyltransferase mixed-lineage leukemia 1 (MLL1) preferentially modifies lysine residue 4 on the unstructured protein tail of histone H3. MLL1 expression and function have been shown to be governed by signal transduction pathways that are activated by inflammatory stimuli, such as NF-κB. Therefore, we sought to investigate the role of MLL1 in mediating macrophage inflammatory responses. Bone marrow-derived macrophages from mice with a targeted MLL1 gene knockout (Lys2-Cre+/- MLL1fx/fx) exhibited decreased proinflammatory gene expression with concurrent decreases in activating histone methylation. However, MLL1-deficient macrophages also exhibited increased phagocytic and bacterial killing activity in vitro. RNA profiling of MLL1-knockout macrophages identified numerous genes involved with inflammatory responses whose expression was altered in response to TLR ligands or proinflammatory cytokines, including STAT4. STAT4-dependent cytokines, such as type I IFNs were able to drive MLL1 expression in macrophages, and MLL1-knockout macrophages exhibited decreased activating histone methylation in the STAT4 promoter. These results implicate an important role for MLL1-dependent epigenetic regulation of macrophage antimicrobial functions.

High prevalence of Group B Streptococcus colonization among pregnant women in Amman, Jordan.

BACKGROUND: Little is known of the burden of Group B Streptococcus (GBS) colonization among pregnant women in Jordan. We conducted a pilot study to determine the prevalence of GBS among pregnant women in Amman, Jordan, where GBS testing is not routine. We also explored GBS serotypes and the performance of a rapid GBS antigen diagnostic test. METHODS: We collected vaginal-rectal swabs from women who presented for labor and delivery at Al-Bashir Hospital. Three methods were used to identify GBS: Strep B Rapid Test (Creative Diagnostics), blood agar media (Remel) with confirmed with BBL Streptocard acid latex test (Becton Dickinson), and CHROMagar StrepB (Remel). Results were read by a senior microbiologist. We defined our gold standard for GBS-positive as a positive blood agar culture confirmed by latex agglutination and positive CHROMagar. PCR testing determined serotype information. Demographic and clinical data were also collected. RESULTS: In April and May 2015, 200 women were enrolled with a median age of 27 years (IQR: 23-32); 89.0% were Jordanian nationals and 71.9% completed secondary school. Median gestational age was 38 weeks (IQR: 37-40); most women reported prenatal care (median 9 visits; IQR: 8-12). Median parity was 2 births (IQR: 1-3). Pre-pregnancy median BMI was 24.1 (IQR: 21.5-28.0) and 14.5% reported an underlying medical condition. Obstetric complications included gestational hypertension (9.5%), gestational diabetes (6.0%), and UTI (53.5%), of which 84.5% reported treatment. Overall, 39 (19.5%) of women were GBS-positive on blood agar media and CHROMagar, while 67 (33.5%) were positive by rapid test (36% sensitivity, 67% specificity). Serotype information was available for 25 (64%) isolates: III (48%), Ia (24%), II (20%), and V (8%). No demographic or clinical differences were noted between GBS+ and GBS-negative women. CONCLUSIONS: Nearly one in five women presenting for labor in Jordan was colonized with GBS, with serotype group III as the most common. The rapid GBS antigen diagnostic had low sensitivity and specificity. These results support expanded research in the region, including defining GBS resistance patterns, serotyping information, and risk factors. It also emphasizes the need for routine GBS testing and improved rapid GBS diagnostics for developing world settings.

Misoprostol protects mice against severe Clostridium difficile infection and promotes recovery of the gut microbiota after antibiotic perturbation.

Clostridium difficile infection (CDI) is one of the most common nosocomial infections worldwide and an urgent public health threat. Epidemiological and experimental studies have demonstrated an association between nonsteroidal anti-inflammatory drug (NSAID) exposure and enhanced susceptibility to, and severity of, CDI. NSAIDs target cyclooxygenase enzymes and inhibit the production of prostaglandins (PGs), but the therapeutic potential of exogenous introduction of PGs for the treatment of CDI has not been explored. In this study, we report that treatment with the FDA-approved stable PGE1 analogue, misoprostol, protects mice against C. difficile-associated mortality, intestinal pathology, and CDI-mediated intestinal permeability. Furthermore, we report that the effect of misoprostol on the gastrointestinal tract contributes to increased recovery of the gut microbiota following antibiotic perturbation. Together, these data implicate PGs as an important host-factor associated with recovery to C. difficile-associated disease and demonstrate the potential for misoprostol in the treatment of CDI. Further studies to explore the safety and efficacy of misoprostol treatment of CDI in humans is needed.

A Unique Case of Burkholderia cepacia Prosthetic Mitral Valve Endocarditis and Literature Review.

Burkholderia cepacia prosthetic valve endocarditis (PVE) is extremely rare, with few cases in the literature. A report of a patient with PVE is described, followed by a literature review on B. cepacia PVE. A 38 year old man with poor dentition and a history of intravenous drug use (IVDU) and mitral valve replacement was found to have a mitral valve vegetation. Five sets of blood cultures on different days grew B. cepacia. Individual sets of blood cultures on different dates also isolated S. viridans (outside hospital culture), methicillin-resistant S. epidermidis (hospital day 1), and Bacillus spp. (hospital day 6). He was successfully treated with ceftazidime and levofloxacin as dual therapy for B. cepacia PVE, in addition to vancomycin for gram positive coverage. This case report and review highlights the possibility of B. cepacia PVE in immunocompetent patients with poor dentition, with the potential for a successful outcome following combination antimicrobial therapy.