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ABSTRACT:
PROVIDER: PRJNA674911 | ENA |
REPOSITORIES: ENA
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Project description:Streptococcus pneumoniae (the pneumococcus) account for significant morbidity and mortality worldwide, causing life-threatening diseases such as pneumonia, bacteremia and meningitis. In this study, we used microarray analysis to compare gene expression patterns of either serotype 4 or serotype 6A pneumococci in the nasopharynx and blood of mice, as a model to identify genes involved in invasion of blood in the context of occult bacteremia in humans.
2015-09-19 | GSE73217 | GEO
Project description:Serratia marcescens is a bacterium frequently found in the environment, but over the last several decades it has evolved into a concerning clinical pathogen, causing fatal bacteremia. To establish such infections, pathogens require specific nutrients; one very limited but essential nutrient is iron. We sought to characterize the iron acquisition systems in S. marcescens isolate UMH9, which was recovered from a clinical bloodstream infection. Using RNA sequencing (RNA-seq), we identified two predicted siderophore gene clusters (cbs and sch) that were regulated by iron. Mutants were constructed to delete each iron acquisition locus individually and in conjunction, generating both single and double mutants for the putative siderophore systems. Mutants lacking the sch gene cluster lost their iron-chelating ability as quantified by the chrome azurol S (CAS) assay, whereas the cbs mutant retained wild-type activity. Mass spectrometry-based analysis identified the chelating siderophore to be serratiochelin, a siderophore previously identified in Serratia plymuthica. Serratiochelin-producing mutants also displayed a decreased growth rate under iron-limited conditions created by dipyridyl added to LB medium. Additionally, mutants lacking serratiochelin were significantly outcompeted during cochallenge with wild-type UMH9 in the kidneys and spleen after inoculation via the tail vein in a bacteremia mouse model. This result was further confirmed by an independent challenge, suggesting that serratiochelin is required for full S. marcescens pathogenesis in the bloodstream. Nine other clinical isolates have at least 90% protein identity to the UMH9 serratiochelin system; therefore, our results are broadly applicable to emerging clinical isolates of S. marcescens causing bacteremia.
2020-05-24 | GSE145587 | GEO
Project description:Persistent methicillin-resistant Staphylococcus aureus (MRSA) bacteremia is life-threatening and occurs in up to 30% of MRSA bacteremia cases despite appropriate antimicrobial therapy. Isolates of MRSA that cause antibiotic-persistent MRSA bacteremia (APMB) typically have in vitro antibiotic susceptibilities equivalent to those causing antibiotic-resolving MRSA bacteremia (ARMB). Thus, persistence reflects host-pathogen interactions occurring uniquely in context of antibiotic therapy in vivo. However, host factors and mechanisms involved in APMB remain unclear. We compared DNA methylomes in circulating immune cells from patients experiencing APMB vs. ARMB. Overall, methylation signatures diverged in the distinct patient cohorts. Differentially methylated sites intensified proximate to transcription factor binding sites, primarily in enhancer regions. In APMB patients, significant hypo-methylation was observed in binding sites for CCAAT enhancer binding protein (C/EBP) and signal transducer / activator of transcription 1 (STAT1). In contrast, hypo-methylation in ARMB patients localized to glucocorticoid receptor and histone acetyltransferase p300 binding sites. These distinct methylation signatures were enriched in neutrophils and achieved a mean area under the curve of 0.85 when used to predict APMB using a classification model. These findings differentiate epigenotypes in patients experiencing APMB vs. ARMB, and suggest a risk stratification strategy for antibiotic persistence in patients treated for MRSA bacteremia.
2021-03-01 | GSE150144 | GEO
Project description:Streptococcus pneumoniae (the pneumococcus) account for significant morbidity and mortality worldwide, causing life-threatening diseases such as pneumonia, bacteremia and meningitis. In this study, we used microarray analysis to compare gene expression patterns of either serotype 4 or serotype 6A pneumococci in the nasopharynx and blood of mice, as a model to identify genes involved in invasion of blood in the context of occult bacteremia in humans. Microarray experiments were performed on whole genome S. pneumoniae PCR arrays obtained from the Bacterial Microarray Group at St George's Hospital Medical School, London (http://bugs.sghms.ac.uk/). The array was designed using TIGR4 base strain annotation and extra target genes from strain R6. Pair-wise comparisons were made between the nasopharynx and blood RNA samples labeled with either Alexa Fluor 546 or Alexa Fluor 647 dye from the 48, 72 and 96 h time points.
2015-09-19 | E-GEOD-73217 | biostudies-arrayexpress
Project description:Urinary tract infections (UTIs) are the second most common infections encountered in the pediatric population, second only to respiratory tract infections. UTIs are also a major cause of morbidity and mortality. UTIs can often ascend causing infection in the upper urinary tract or even progress to bacteremia or urosepsis. Urosepsis accounts for 10-30% of septic shock cases and Uropathogenic E.coli (UPEC) is responsible for almost 75% of cases. Therefore, increased understanding of the effects of urosepsis at the cellular and organ specific level will provide the foundation for improvements in clinical care.
2020-10-26 | GSE160038 | GEO
Project description:Interventions: Analysis of bacteremia after ESD of the colon.
Primary outcome(s): Identification of bacteremia after ESD testing blood culture and 16SrRNA gene sequencing.
Study Design: Single arm Non-randomized
| 2623655 | ecrin-mdr-crc