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Item Antibacterial and Anti-biofilm Activity of the Human Breast Milk Glycoprotein Lactoferrin against Group B Streptococcus(Wiley, 2021) Lu, Jacky; Francis, Jamisha D.; Guevara, Miriam A.; Doster, Ryan S.; Eastman, Alison J.; Rogers, Lisa M.; Noble, Kristin N.; Manning, Shannon D.; Damo, Steven M.; Aronoff, David M.; Townsend, Steven D.; Gaddy, Jennifer A.; Medicine, School of MedicineGroup 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.Item Binding of oral veillonella species to saliva-coated hydroxyapatite(1993) Wu, Sonya L.; Hughes, Christopher V.; Gregory, Richard L.; Sanders, Brian J.; Bowman, Dennis E.; Avery, David R.Veillonella spp. are found in high numbers in the mouth in dental plaque and on the mucosa. Veillonellae utilize lactic acid for their metabolic needs. A symbiotic relationship between Veillonellae and other oral bacteria, including a nutritional relationship with some streptococci, has been demonstrated both in vitro and in vivo. Thus, Veillonellae may protect the host from dental caries. Adherence is the initial step in bacterial colonization of oral surfaces. Recent evidence suggests that certain oral bacteria express molecules (adhesins) on their cell surface, which recognize receptors on other oral bacteria and/or in salivary pellicle. It has been previously demonstrated that Veillonella spp. bind avidly to Streptococcus. spp. found in subgingival plaque. The present study investigated the ability of V. atypica PK1910 to bind to saliva-coated hydroxyapatite (SHA), a model for adherence to the salivary pellicle. The results show that there was statistically significant enhanced binding of Veillonella atypica PK1910 to saliva-coated hydroxyapatite beads. (p< 0.05) Three classes of coaggregation-defective mutants of V. atypica PK1910 were tested for their ability to bind to SHA. Interestingly, they did not demonstrate any enhanced binding to saliva-coated hydroxyapatite beads. Heating of PK1910 did not effect binding to SHA. In contrast, protease treatment of the veillonella cell surface inactivated binding. Therefore, it appears that V. atypica PK1910, in addition to binding to oral Streptoccoccus spp. in dental plaque, may also colonize the tooth surface by binding directly to the salivary pellicle. It appears that a distinct heat stable protein may mediate this binding to SHA.Item Group B Streptococcus cpsE is required for serotype V capsule production and aids in biofilm formation and ascending infection of the reproductive tract during pregnancy(American Chemical Society, 2021) Noble, Kristen; Lu, Jacky; Guevara, Miriam A.; Doster, Ryan S.; Chambers, Schuyler A.; Rogers, Lisa M.; Moore, Rebecca E.; Spicer, Sabrina K.; Eastman, Alison J.; Francis, Jamisha D.; Manning, Shannon D.; Rajagopal, Lakshmi; Aronoff, David M.; Townsend, Steven D.; Gaddy, Jennifer A.; Pediatrics, School of MedicineGroup B Streptococcus (GBS) is an encapsulated Gram-positive pathogen that causes ascending infections of the reproductive tract during pregnancy. The capsule of this organism is a critical virulence factor that has been implicated in a variety of cellular processes to promote pathogenesis. Primarily comprised of carbohydrates, the GBS capsule and its synthesis is driven by the capsule polysaccharide synthesis (cps) operon. The cpsE gene within this operon encodes a putative glycosyltransferase that is responsible for the transfer of a Glc-1-P from UDP-Glc to an undecaprenyl lipid molecule. We hypothesized that the cpsE gene product is important for GBS virulence and ascending infection during pregnancy. Our work demonstrates that a GBS cpsE mutant secretes fewer carbohydrates, has a reduced capsule, and forms less biofilm than the wild-type parental strain. We show that, compared to the parental strain, the ΔcpsE deletion mutant is more readily taken up by human placental macrophages and has a significantly attenuated ability to invade and proliferate in the mouse reproductive tract. Taken together, these results demonstrate that the cpsE gene product is an important virulence factor that aids in GBS colonization and invasion of the gravid reproductive tract.Item Streptococcus agalactiae npx Is Required for Survival in Human Placental Macrophages and Full Virulence in a Model of Ascending Vaginal Infection during Pregnancy(American Society for Microbiology, 2022-11-21) Lu, Jacky; Moore, Rebecca E.; Spice, Sabrina K.; Doster, Ryan S.; Guevara, Miriam A.; Francis, Jamisha D.; Noble, Kristen N.; Rogers, Lisa M.; Talbert, Julie A.; Korir, Michelle L.; Townsend, Steven D.; Aronoff, David M.; Manning, Shannon D.; Gaddy, Jennifer A.; Medicine, School of MedicineStreptococcus agalactiae, also known as group B Streptococcus (GBS), is a Gram-positive encapsulated bacterium that colonizes the gastrointestinal tract of 30 to 50% of humans. GBS causes invasive infection during pregnancy that can lead to chorioamnionitis, funisitis, preterm prelabor rupture of membranes (PPROM), preterm birth, neonatal sepsis, and maternal and fetal demise. Upon infecting the host, GBS encounters sentinel innate immune cells, such as macrophages, within reproductive tissues. Once phagocytosed by macrophages, GBS upregulates the expression of the gene npx, which encodes an NADH peroxidase. GBS mutants with an npx deletion (Δnpx) are exquisitely sensitive to reactive oxygen stress. Furthermore, we have shown that npx is required for GBS survival in both THP-1 and placental macrophages. In an in vivo murine model of ascending GBS vaginal infection during pregnancy, npx is required for invading reproductive tissues and is critical for inducing disease progression, including PPROM and preterm birth. Reproductive tissue cytokine production was also significantly diminished in Δnpx mutant-infected animals compared to that in animals infected with wild-type (WT) GBS. Complementation in trans reversed this phenotype, indicating that npx is critical for GBS survival and the initiation of proinflammatory signaling in the gravid host.