68 research outputs found
Wheat and Maize Flour Fortification: Practical Recommendations for National Application
Joint statement by the World Health Organization, Food and Agriculture Organization of the United Nations, The United Nations Children s Fund, Global Alliance for Improved Nutrition, The Micronutrient Initiative and The Flour Fortification InitiativeREPRODUCTIVE HEALTHSURVEILLANCE AND INVESTIGATIONCURREN
Blood borne: Bacterial components in mother’s blood influence fetal development: DOI: 10.14800/ics.1421
Bacterial or viral infection of the mother during the course of pregnancy can cross the placenta and actively infect the fetus. However, especially for bacteria, it is more common for mothers to experience an infection that can be treated without overt fetal infection. In this setting, it is less well understood what the risk to fetal development is, particularly in terms of neurological development. This research highlight reviews recent findings indicating that bacterial components generated during infection of the mother can cross the placenta and activate the fetal innate immune system resulting in changes in the course of brain development and subsequent progression to postnatal cognitive disorders. Bacterial cell wall is a ubiquitous bacterial PAMP (pathogen-associated molecular pattern) known to activate inflammation through the stimulation of TLR2. Cell wall is released from bacteria during antibiotic treatment and new work shows that embryos exposed to cell wall from the mother demonstrate anomalous proliferation of neuronal precursor cells in a TLR2 dependent manner. Such proliferation increases the neuronal density of the cortical plate and alters brain architecture. Although there is no fetal death, subsequent cognitive development is significantly impaired. This model system suggests that bacterial infection of the mother and its treatment can impact fetal brain development and requires greater understanding to potentially eliminate a risk factor for cognitive disorders such as autism
Revising the Role of the Pneumococcal vex-vncRS Locus in Vancomycin Tolerance
Vancomycin is used increasingly to treat invasive infections caused by multidrug-resistant Streptococcus pneumoniae. Although no vancomycin-resistant strains have been isolated to date, tolerant strains that fail to die rapidly and that cause relapsing disease have been described. The vex123-pep(27)-vncRS locus, consisting of an ABC transporter, a presumed signaling peptide, and a two-component system, respectively, has been implicated in vancomycin tolerance. Recent findings, however, challenged this model. The data presented here indicate that erythromycin in the growth medium induces a vancomycin-tolerant phenotype and that loss of function of Pep(27) or VncRS does not alter autolysis. However, a role for the ABC transporter encoded by the vex123 genes in tolerance was confirmed. A vex3 mutant was considerably more tolerant to vancomycin treatment than the wild-type strain T4, and the strength of the phenotype depended on the orientation of the resistance cassette used to construct the mutant. Microarray results suggested a number of genes that might be involved in tolerance in the vex3 mutant. Although the exact function and regulation of the vex123-pep(27)-vncRS locus remains to be determined, several factors influence the autolysis behavior of S. pneumoniae, including the bacterial capsule, erythromycin, and the lytA and vex3 gene products
Quinupristin-Dalfopristin Nonsusceptibility in Pneumococci from Sickle Cell Disease Patients
Sickle cell disease (SCD) is a risk factor for fatal pneumococcal infection. Nonsusceptibilty to quinupristin-dalfopristin (Q-D) was absent from 105 non-SCD-associated pneumococcal isolates but was present in 33/148 (22%) SCD-associated isolates. One-third of the isolates harbored a known resistance mechanism. Q-D is not optimal for use for the treatment of pneumococcal infection in SCD patients
Identification of a Candidate Streptococcus pneumoniae Core Genome and Regions of Diversity Correlated with Invasive Pneumococcal Disease
Streptococcus pneumoniae is a leading cause of community-acquired pneumonia and gram-positive sepsis. While multiple virulence determinants have been identified, the combination of features that determines the propensity of an isolate to cause invasive pneumococcal disease (IPD) remains unknown. In this study, we determined the genetic composition of 42 invasive and 30 noninvasive clinical isolates of serotypes 6A, 6B, and 14 by comparative genomic hybridization. Comparison of the present/absent gene matrix (i.e., comparative genomic analysis [CGA]) identified a candidate core genome consisting of 1,553 genes (73% of the TIGR4 genome), 154 genes whose presence correlated with the ability to cause IPD, and 176 genes whose presence correlated with the noninvasive phenotype. Genes identified by CGA were cross-referenced with the published signature-tagged mutagenesis studies, which served to identify core and IPD-correlated genes required for in vivo passage. Among these, two pathogenicity islands, region of diversity 8a (RD8a), which encodes a neuraminidase and V-type sodium synthase, and RD10, which encodes PsrP, a protein homologous to the platelet adhesin GspB in Streptococcus gordonii, were identified. Mice infected with a PsrP mutant were delayed in the development of bacteremia and demonstrated reduced mortality versus wild-type-infected controls. Finally, the presence of seven RDs was determined to correlate with the noninvasive phenotype, a finding that suggests some RDs may contribute to asymptomatic colonization. In conclusion, RDs are unequally distributed between invasive and noninvasive isolates, RD8a and RD10 are correlated with the propensity of an isolate to cause IPD, and PsrP is required for full virulence in mice
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