Co-adaptation of Streptococcus mutans to simulated microgravity and silver nitrate

To sustain life on extended space missions, it is essential to maintain clean potable water. NASA currently uses iodine as the primary biocide in the potable water dispenser on the International Space Station and has recently proposed a potential switch to silver-based antimicrobials. Streptococcus mutans is the primary etiological agent of dental caries, part of the normal oral flora, and would endure direct exposure to water from the potable water dispenser. In our previous work, we examined the 100-day adaptive response of Streptococcus mutans to simulated microgravity (sMG). Here, we examined the evolutionary co-adaptation of S. mutans under sMG and silver nitrate (AgNO3) to evaluate the consequences of using silver as a primary biocide in space and the impact on the evolution of microbes from the oral microbiome. To do this, we adapted four populations of S. mutans under sMG and co-adapted four populations in simulated microgravity and silver nitrate using high-aspect ratio vessels for 100 days. Genomic analysis at multiple time points showed that S. mutans in sMG evolved variants consistent with our previous findings (SMU_1307c and SMU_399) while also acquiring novel mutations in the glutathione reductase gorA. The co-adapted populations showed mutations specific for the environment in ciaH/R, PBP1a, trkA, and trkB. We also assessed virulence phenotypes, and while simulated microgravity increased antibiotic susceptibility, sucrose-dependent adhesion, and, in some populations, acid tolerance, co-adaptation to silver nitrate reversed these effects. Overall, these data show that the use of silver as a biocide in simulated microgravity can evolve strains with novel genotypic and phenotypic traits that could alter virulence

Gestational diabetes and childhood asthma in a racially diverse US pregnancy cohort

BackgroundChildhood asthma is a common chronic disease that likely has prenatal origins. Gestational diabetes alters maternal physiology and may influence fetal risk for childhood-onset disease. However, the association between gestational diabetes and child asthma is not well characterized.ObjectiveTo investigate the association between gestational diabetes and wheeze/asthma at approximately 4 years of age in a racially diverse US cohort.MethodsWe studied mother-child dyads enrolled prenatally in the Conditions Affecting Neurocognitive Development and Learning in Early Childhood study. Gestational diabetes was determined by medical chart review. At approximately 4 years of age, we assessed child respiratory outcomes including parent report of physician-diagnosed asthma (ever), current wheeze (symptoms within the past 12 months), and current asthma (physician diagnosis and/or medication or symptoms within the past 12 months). We used the modified Poisson regression to assess associations between gestational diabetes and child respiratory outcomes, adjusting for maternal age, race, prenatal smoking, pre-pregnancy body mass index, parity, asthma history, socioeconomic status, and infant sex.ResultsAmong 1107 women, 66% were African American/Black. Six percent (n = 62) had gestational diabetes documented during pregnancy. Gestational diabetes was associated with increased risk of physician-diagnosed asthma (adjusted risk ratio (RR) [95% Confidence Interval]: 2.13 [1.35, 3.38]; prevalence: 14%), current wheeze (RR: 1.85 [1.23, 2.78]; prevalence: 19%), and current asthma (RR: 2.01 [1.30, 3.10]; prevalence: 16%).ConclusionsGestational diabetes was associated with increased risk of asthma and wheeze outcomes. Additional studies are needed to elucidate modifiable pathways underlying this association

Gestational diabetes and childhood asthma in a racially diverse US pregnancy cohort

BACKGROUND: Childhood asthma is a common chronic disease that likely has prenatal origins. Gestational diabetes alters maternal physiology and may influence fetal risk for childhood onset disease. However, the association between gestational diabetes and child asthma is not well characterized. OBJECTIVE: To investigate the association between gestational diabetes and wheeze/asthma at approximately 4 years of age in a racially diverse U.S. cohort. METHODS: We studied mother-child dyads enrolled prenatally in the Conditions Affecting Neurocognitive Development and Learning in Early Childhood study. Gestational diabetes was determined by medical chart review. At approximately 4 years of age, we assessed child respiratory outcomes including parent report of physician-diagnosed asthma (ever), current wheeze (symptoms within the past 12 months), and current asthma (physician diagnosis and/or medication or symptoms within the past 12 months). We used modified Poisson regression to assess associations of gestational diabetes and child respiratory outcomes, adjusting for maternal age, race, prenatal smoking, pre-pregnancy body mass index, parity, asthma history, socioeconomic status and infant sex. RESULTS: Among 1,107 women, 66% were African-American/Black. Six percent (n=62) had gestational diabetes documented during pregnancy. Gestational diabetes was associated with increased risk of physician-diagnosed asthma (adjusted risk ratio (RR) [95% Confidence Interval]: 2.13 [1.35, 3.38]; prevalence: 14%), current wheeze (RR: 1.85 [1.23, 2.78]; prevalence: 19%) and current asthma (RR: 2.01 [1.30, 3.10]; prevalence: 16%). CONCLUSIONS: Gestational diabetes was associated with increased risk of asthma and wheeze outcomes. Additional studies are needed to elucidate modifiable pathways underlying this association