Project description:Bacteria spatially confine cellular processes like protease secretion and signal transduction in membrane platforms termed functional membrane microdomains, which in certain organisational and functional features resemble the lipid rafts of eukaryotic cells. However, a rigorous understanding of their composition, assembly and biological significance is unknown. Here we use the human pathogen methicillin-resistant Staphylococcus aureus (MRSA) to show that the organization of these platforms requires a preferential interaction between unphosphorylated membrane saccharolipids and the scaffold protein flotillin. This interaction leads to their accumulation in specific membrane microdomains concomitantly to the attraction of membrane-associated multimeric complexes, for which flotillin promotes efficient oligomerization. One of these harbored proteins is the penicillin-binding protein PBP2a, responsible for penicillin resistance in MRSA. We took PBP2a as showcase to demonstrate that flotillin mutants are also defective in PBP2a oligomerization and activity. Thus, perturbation of microdomains assembly, using commercially available drugs, interferes with PBP2a oligomerization and causes a relapse of MRSA penicillin resistance in vitro and in vivo, resulting in MRSA infections susceptible to conventional penicillin treatments. Our study shows that bacterial cells organize sophisticated programs for cellular compartmentalization and unravels a novel strategy to develop antimicrobial therapies for multi-drug resistance pathogens.
Project description:S. aureus ATCC 25923 is performance standard for antimicrobial susceptibility testing. S. aureus ATCC 33591 showed resistance against erytrhromycin, penicillin, and streptomycin. We used microarray to compare RNA expression between sensitive and resistant strain of S. aureus as a preliminary research for MRSA inhibition.
Project description:A recent study reported that daptomycin-resistant MRSA (DAPR) strain biofilm is more resistant to daptomycin and vancomycin, as compared to the WT strain biofilm. This pose a great danger since DAPR MRSA is prevalent in clinics and they often form biofilms in medical devices. In this study, we investigate the anti-biofilm activity of elasnin against DAPR MRSA biofilms, and we observed that elasnin is not only effective to eradicate the biofilm of the DAPR strain, but it shows a superior activity compared to the susceptible WT strain. Using proteomics, we compared the proteome profile of the DAPR and the WT strain biofilm cells under elasnin treatment to reveal why elasin is superior against the DAPR strain. Besides, we also employed adaptive laboratory evolution (ALE) experiment by repetitively treating MRSA culture with high dose of elasnin, and generated evolved MRSA strain with increased elasnin tolerance. Using quantitative proteomics, we compared the proteome differences in the elasnin-susceptible WT MRSA and elasnin-tolerant evolved strain.
Project description:Methicillin-resistant Staphylococcus aureus (MRSA) is a major human pathogen in both community and health care settings, which causes a wide range of infections. Its resistance to β-lactam antibiotics and methicillin in particular, greatly complicates treatment options and success rate due to the limited number of antibiotics with activity against MRSA. To further the development of alternative therapeutics, the mechanisms that mediate antibiotic resistance in MRSA need to be fully understood. Cannabinoid compounds including cannabidiol (CBD), tetrahydrocannabinol (THC) and cannabinol (CBN) have shown promise as potential antibiotic adjuvants. In the present study, MRSA cells were subjected to antibiotic stress from methicillin in combination with three cannabinoid compounds, and subsequently analysed using metaproteomics to assess the metabolic response. Subjecting MRSA to methicillin made the cells more viable and increased their energy production, as well as upregulation of penicillin-binding protein 2 (PBP2). The cannabinoids all showed antimicrobial activity against MRSA, and inhibited the energy production of the cells as well as PBP2 when used in combination with methicillin. Furthermore, all three cannabinoid compounds inhibited resistance mechanisms in MRSA, resulting in a decrease in the minimum inhibitory concentration (MIC) of methicillin when used in combination.
2022-01-18 | PXD024244 | Pride
Project description:Heterogeneity of penicillin non-susceptible Group B streptococci
Project description:Cefquinome is a fourth-generation cephalosporin developed specifically for veterinary use. The mechanism of MRSA resistance to cefquinome is still not established. Therefore, we designed this study to evaluate the effect of cefquinome on the transcriptome of MRSA1679a, a strain that was isolated from a chicken. The transcriptome analysis indicated that multiple efflux pumps (QacA, NorB, Bcr, and ABCb) were upregulated in MRSA1679a as a resistance mechanism to expel cefquinome. Additionally, penicillin-binding protein 1A was overexpressed, which conferred resistance to cefquinome, a β-lactam antibiotic. Adhesion and the biofilm-forming capacity of the MRSA strain was also enhanced in addition to overexpression of many stress-related genes. Genes related to carbohydrate metabolism, secretion systems, and transport activity were also significantly increased in MRSA1679a. In conclusion, global transcription was triggered to overcome the stress induced by cefquinome, and the MRSA1679a showed a great genetic potential to survive in this challenging environment. This study provides a profound understanding of MRSA1679a as a potentially important pathogen and identifies key resistance characteristics of MRSA against cefquinome.
Project description:S. aureus ATCC 25923 is performance standard for antimicrobial susceptibility testing. S. aureus ATCC 33591 showed resistance against erytrhromycin, penicillin, and streptomycin. We used microarray to compare RNA expression between sensitive and resistant strain of S. aureus as a preliminary research for MRSA inhibition. S. aureus strains were cultivated in tryptic soy broth at 37℃ for 18hrs and harvested for RNA extraction and hybridization on Affymetrix microarrays.
Project description:S. aureus and MRSA are susceptible to TTO and are therefore targeted in nascent TTO clinical trails. We now report the alterations in the transcriptome of a S. aureus exposed to a growth inhibitory concentration of TTO. These efforts have uncovered additional mechanisms by which this membrane active antimicrobial substance inhibits bacterial growth.
Project description:Purpose: Staphylococcus aureus is a highly successful human pathogen responsible for wide range of infections. In this study, we provide insights into the virulence, pathogenicity, and antimicrobial resistance determinants of methicillin susceptible and methicillin resistant Staphylococcus aureus (MSSA; MRSA) recovered from non-healthcare environments. Experiment design: Three environmental MSSA and three environmental MRSA were selected for proteomic profiling using iTRAQ MS/MS. Gene Ontology (GO) Annotation and Kyoto Encyclopedia of Genes and Genomes (KEGG) Pathway Annotation were applied to interpret the functions of the proteins detected. Results: 792 proteins were identified in MSSA and MRSA. Comparative analysis of MRSA and MSSA revealed that 8 of out 792 proteins were up-regulated and 156 down-regulated. Differentially abundant proteins were predominantly involved in catalytic and binding activity. Among 164 proteins that had differences in abundance, 29 proteins were involved in pathogenesis, antimicrobial activities,stress response, mismatch repair and cell wall synthesis. Twenty-two proteins associated with pathogenicity, including spa, sbi, clfA and dlt were up-regulated in MRSA. Moreover, the up-regulated pathogenic protein entC2 in MSSA was determined to be a super antigen potentially capable of triggering toxic shock syndrome in the host. Conclusions: Enhanced pathogenicity, antimicrobial activity and stress response were observed in MRSA compared to MSSA.
Project description:Recurrent epidemics of methicillin-resistant Staphylococcus aureus (MRSA) have illustrated that the effectiveness of antibiotics in clinical application is rapidly fading. A feasible approach is to combine natural products with existing antibiotics to achieve an antibacterial effect. In this molecular docking study, we found that theaflavin (TF) preferentially binds the allosteric site of penicillin-binding protein 2a (PBP2a), inducing the PBP2a active site to open, which is convenient for β-lactam antibiotics to treat MRSA infection, instead of directly exerting antibacterial activity at the active site. Subsequent TMT-labeled proteomics analysis showed that TF treatment did not significantly change the landscape of the Staphylococcus aureus (S. aureus) USA300 proteome.Checkerboard dilution tests and kill curve assays were performed to validate the synergistic effect of TF and ceftiofur, and the fractional inhibitory concentration index (FICI) was 0.1875.Our findings provide a potential therapeutic strategy to combine existing antibiotics with natural products to resolve the prevalent infections of multidrug-resistant pathogens.