Project description:Isoquinolines (IQs) are natural substances with antibiotic potential. IQ-238 is a synthetic analog of the novel-type N,C-coupled naphtylisoquinoline (NIQ) alkaloid ancisheynine. Gene expression data, cytotoxicity measurements and metabolic modelling is combined to assess the effects of the N,C-coupled naphtylisoquinoline (NIQ) compound IQ-238 on Staphylococcus aureus and man as a potential lead for novel antibiotics. It possesses a high activity against staphylococci but has low cytotoxicity in human cell lines. Genome annotation identified missed enzymes (validated by PCR) in the primary (e.g. nucleotide) metabolism of staphylococci. Gene expression changed after cultivation with IQ-238. Metabolic modelling did yield the adaptations of all central enzymes, including those not affected by significant gene expression changes. The data show that IQ-238 interferes with the carbohydrate metabolism in staphylococci. The data suggest that IQ-238 is a promising lead for antibiotic therapy against S. aureus infections.
Project description:Isoquinolines (IQs) are natural substances with antibiotic potential. IQ-238 is a synthetic analog of the novel-type N,C-coupled naphtylisoquinoline (NIQ) alkaloid ancisheynine. Gene expression data, cytotoxicity measurements and metabolic modelling is combined to assess the effects of the N,C-coupled naphtylisoquinoline (NIQ) compound IQ-238 on Staphylococcus aureus and man as a potential lead for novel antibiotics. It possesses a high activity against staphylococci but has low cytotoxicity in human cell lines. Genome annotation identified missed enzymes (validated by PCR) in the primary (e.g. nucleotide) metabolism of staphylococci. Gene expression changed after cultivation with IQ-238. Metabolic modelling did yield the adaptations of all central enzymes, including those not affected by significant gene expression changes. The data show that IQ-238 interferes with the carbohydrate metabolism in staphylococci. The data suggest that IQ-238 is a promising lead for antibiotic therapy against S. aureus infections. HG001 WT strain exposed to GB-AP-238 in rich medium
Project description:Staphylococci are major pathogens in humans and animals and emerging antibiotic-resistant strains have further increased the importance of this health issue. The existence of a genetic basis of host response to bacterial infections has been widely documented but the underlying mechanisms and genes are still largely unknown. Previously, two divergent lines of sheep selected on their milk somatic cell count called high and low SCS lines, have been showed to be respectively more and less susceptible to intra mammary infections (IMI). Transcriptional profiling of milk somatic cells (MSC) of high and low SCS sheep infected successively by S. epidermidis and S. aureus was performed to provide enhanced knowledge about the genetic basis of differential host response to IMI with Staphylococci. Gene expression in MSC of high and low SCS sheep collected 12h post-challenge was performed on a 15K gene ovine oligoarray (Agilent). MSC were mainly neutrophils. The high number of differentially expressed genes between the two bacterial strains indicated, among others, increased number of T-cells in MSC after S. aureus, compared to S. epidermidis challenge. Differential regulation of 366 genes between resistant and susceptible animals was largely associated with immune and inflammatory response (including pathogen recognition TLR2 pathway and cell migration), signal transduction, cell proliferation and apoptosis. Close biological connection between most of differentially expressed genes into Ingenuity Pathway Analysis networks further indicated consistency between the genes that were differentially-expressed between resistant and susceptible animals. Gene profiling in high and low SCS sheep provided strong candidates for biological pathway and gene underlying genetically determined resistance and susceptibility towards Staphylococci infections opening new fields for further investigation. Keywords: Staphylococcus epidermidis, Staphylococcus aureus, milk somatic cells, mammalian, transcriptome, immunity, mastitis 22 samples in a two-colour dye-swap experimental design
Project description:S. aureus and S. epidermidis were challenged with D-sphingosine, an antimicrobial lipid similar to sphingosines found in the major staphylococcal niche- human skin. Comparison of responses was used to identify resistance mechanisms and likely mode of action
Project description:Staphylococcus aureus Newman and Staphylococcus epidermidis Tu3298, 20 minutes post challenge with sub-inhibitory concentration of sapienic acid vs equivalent concentration of ethanol. Challenge was added at mid logarithmic growth (OD600 0.5). Biological triplicates of samples were sequenced.
Project description:Bacterial persister cells are phenotypic variants that exhibit a transient non-growing state and antibiotic tolerance. Here we provide in vitro evidence of Staphylococcus aureus persisters within infected host cells. We show that the bacteria surviving antibiotic treatment within host cells are persisters, displaying biphasic killing and reaching a uniformly non-responsive, non-dividing state when followed at the single-cell level. This phenotype is stable but reversible upon antibiotic removal. Intracellular S. aureus persisters remain metabolically active, but display an altered transcriptomic profile consistent with activation of stress responses, including the stringent response as well as cell-wall stress, SOS and heat-shock responses. These changes are associated with multidrug tolerance after exposure to a single antibiotic. We hypothesize that intracellular S. aureus persisters may constitute a reservoir for relapsing infection, and could contribute to therapeutic failures.
Project description:Staphylococci are major pathogens in humans and animals and emerging antibiotic-resistant strains have further increased the importance of this health issue. The existence of a genetic basis of host response to bacterial infections has been widely documented but the underlying mechanisms and genes are still largely unknown. Previously, two divergent lines of sheep selected on their milk somatic cell count called high and low SCS lines, have been showed to be respectively more and less susceptible to intra mammary infections (IMI). Transcriptional profiling of milk somatic cells (MSC) of high and low SCS sheep infected successively by S. epidermidis and S. aureus was performed to provide enhanced knowledge about the genetic basis of differential host response to IMI with Staphylococci. Gene expression in MSC of high and low SCS sheep collected 12h post-challenge was performed on a 15K gene ovine oligoarray (Agilent). MSC were mainly neutrophils. The high number of differentially expressed genes between the two bacterial strains indicated, among others, increased number of T-cells in MSC after S. aureus, compared to S. epidermidis challenge. Differential regulation of 366 genes between resistant and susceptible animals was largely associated with immune and inflammatory response (including pathogen recognition TLR2 pathway and cell migration), signal transduction, cell proliferation and apoptosis. Close biological connection between most of differentially expressed genes into Ingenuity Pathway Analysis networks further indicated consistency between the genes that were differentially-expressed between resistant and susceptible animals. Gene profiling in high and low SCS sheep provided strong candidates for biological pathway and gene underlying genetically determined resistance and susceptibility towards Staphylococci infections opening new fields for further investigation. Keywords: Staphylococcus epidermidis, Staphylococcus aureus, milk somatic cells, mammalian, transcriptome, immunity, mastitis
Project description:We have previously shown that celecoxib, a selective COX-2 inhibitor, in combination with antibiotic sensitizes S aureus to antibiotic thereby decreasing the MIC of antibiotic. The present study is aimed at understanding the molecular mechanism of action of celecoxib on S aureus growth by microarray analysis. The results were analysed and the data clearly shows global change in the expression levels of S aureus genes in presence of celecoxib. Many virulence genes, essential genes and nonessential genes are down-regulated in presence of celecoxib in combination with ampicillin when compared to drug treatment alone.