ABSTRACT: Whole genome analysis of MDR Klebsiella pneumoniae strains isolated from Hospital acquired infections in tertiary hospitals in Dakar, Senegal.
Project description:To gain insight into the alterations of gene expression profile in the course of non-mutationally acquired resistance, we performed RNA-seq comparing MDR persister cells to MDR cancer cells.
Project description:The epidemic community-acquired methicillin-resistant S. aureus (CA-MRSA) clone USA300 has recently become a leading cause of hospital-associated bloodstream infections (BSI). Leveraging this recent introduction into hospitals and the limited genetic variation across the USA300 strains, we combined microbial comparative genomics with phenotypic analyses to discover adaptive mutations. USA300 isolates from BSI were found to have independently evolved single nucleotide variants in the transcriptional regulator sarZ. sarZ inactivation lead to altered expression of virulence factors, resulting in increased lethality in a murine model of BSI. Thus, USA300 strains can optimize their fitness in hospitals through evolution of higher virulence.
Project description:The emergence of multidrug resistant (MDR) Mycobacterium tuberculosis (Mtb) strains, resistant to the frontline anti-tubercular drugs rifampicin and isoniazid, forces treatment with less effective and toxic second-line drugs and stands to derail TB control efforts. However, the immune response to MDR Mtb infection remains poorly understood. Here, we determined the RNA transcriptional profile of in vitro generated macrophages to infection with either drug susceptible Mtb HN878 or MDR Mtb W_7642 infection.
Project description:Liao2011 - Genome-scale metabolic
reconstruction of Klebsiella pneumoniae (iYL1228)
This model is described in the article:
An experimentally validated
genome-scale metabolic reconstruction of Klebsiella pneumoniae
MGH 78578, iYL1228.
Liao YC, Huang TW, Chen FC,
Charusanti P, Hong JS, Chang HY, Tsai SF, Palsson BO, Hsiung
CA.
J. Bacteriol. 2011 Apr; 193(7):
1710-1717
Abstract:
Klebsiella pneumoniae is a Gram-negative bacterium of the
family Enterobacteriaceae that possesses diverse metabolic
capabilities: many strains are leading causes of
hospital-acquired infections that are often refractory to
multiple antibiotics, yet other strains are metabolically
engineered and used for production of commercially valuable
chemicals. To study its metabolism, we constructed a
genome-scale metabolic model (iYL1228) for strain MGH 78578,
experimentally determined its biomass composition,
experimentally determined its ability to grow on a broad range
of carbon, nitrogen, phosphorus and sulfur sources, and
assessed the ability of the model to accurately simulate growth
versus no growth on these substrates. The model contains 1,228
genes encoding 1,188 enzymes that catalyze 1,970 reactions and
accurately simulates growth on 84% of the substrates tested.
Furthermore, quantitative comparison of growth rates between
the model and experimental data for nine of the substrates also
showed good agreement. The genome-scale metabolic
reconstruction for K. pneumoniae presented here thus provides
an experimentally validated in silico platform for further
studies of this important industrial and biomedical
organism.
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MODEL1507180054.
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Project description:Traditional vaccines are difficult to deploy against the diverse antibiotic-resistant, nosocomial pathogens that cause Hospital Acquired Infections (HAIs). We developed a unique, protein-free vaccine to present antibiotic-resistant HAIs. This vaccine protected mice from invasive infections caused by methicillin-resistant Staphylococcus aureus, vancomycin-resistant Enterococcus faecalis, multidrug resistant Acinetobacter baumannii, Klebsiella pneumoniae, Pseudomonas aeruginosa, Rhizopus delemar, and Candida albicans. Protection persisted even in neutropenic mice infected with A. baumannii or R. delemar. Protection was already apparent after 24 hours and lasted for up to 21 days after a single dose, with a second dose restoring efficacy. Protection persisted without lymphocytes but was abrogated with macrophages depletion. This vaccine induced trained immunity by altering the macrophage epigenetic landscape and the inflammatory response to infection.
Project description:The study aimed to characterize plasmids mediating carbepenem resistance in Klebsiella pneumoniae in Pretoria, South Africa. We analysed 56 K. pneumoniae isolates collected from academic hospital around Pretoria. Based on phenotypic and molecular results of these isolates, 6 representative isolates were chosen for further analysis using long reads sequencing platform. We observed multidrug resistant phenotype in all these isolates, including resistance to aminoglycosides, tetracycline, phenicol, fosfomycin, floroquinolones, and beta-lactams antibiotics. The blaOXA-48/181 and blaNDM-1/7 were manily the plasmid-mediated carbapenemases responsible for carbapenem resistance in the K. pneumoniae isolates in these academic hospitals. These carbapenemase genes were mainly associated with plasmid replicon groups IncF, IncL/M, IncA/C, and IncX3. This study showed plasmid-mediated carbapenemase spread of blaOXA and blaNDM genes mediated by conjugative plasmids in Pretoria hospitals.
Project description:Regulatory RNAs (sRNAs) are now considered as major players in many physiological and adaptive responses in pathogenic bacteria. sRNAs have been extensively studied in Gram-negative bacteria, but less information is available in Gram-positive pathogens. There is a spread of multidrug-resistant (MDR) opportunistic organisms, grouped as “ESKAPE” pathogens, which comprise enterococci, a leading cause of hospital-acquired infections and outbreaks with emergence of MDR isolates, especially vancomycin-resistant Enterococcus faecium (VREF). Note that no information about sRNA expression is known in this major opportunistic pathogen. By transcriptomic and genomic analyses using E. faecium Aus0004 reference strain, 249 transcribed IGRs, including sRNA candidates, were detected and, using a series of cut-offs, this set was lowered down to 54 sRNAs while 7 that were predicted based on comparative sequence analysis. RNA-seq was performed with and without subinhibitory concentrations (SIC) of daptomycin, a cyclic lipopeptide antibiotic used for VREF infections. Under daptomycin SIC exposure, 260 genes (9.1% of the genome) had a significant alteration of expression including 80 upregulated genes and 180 downregulated genes. Among the repressed genes, a large proportion (55%) coded for proteins involved in carbohydrate and transport metabolism. Also, we focused on the 9 sRNAs exhibiting the highest expression, and all of them were confirmed as expressed along bacterial growth by Northern blots and qPCR. Out of these 9 sRNAs, four had significantly lower or higher expression in the presence of daptomycin SIC, and therefore responded to antibiotic exposure. Finally, we also tested the expression of these 9 sRNAs in a collection of isogenic Aus0004 mutants with increasing levels of daptomycin resistance, and we observed by qPCR that some sRNAs had a significantly modified expression in daptomycin resistance mutants. It highlights the significant implication of some of the E. faecium sRNAs in the early steps of the development of daptomycin resistance. This is the first experimental genome-wide sRNA identification in Gram-positive E. faecium, a leading cause of hospital acquired infections.