ABSTRACT: Heterogeneity in antimicrobial resistance traits among multidrug resistant Gram-negative bacterial pathogens isolated from India: phenotypic, genotypic and proteomic analyses
Project description:Heterogeneity in antimicrobial resistance traits among multidrug resistant Gram-negative bacterial pathogens isolated from India: phenotypic, genotypic and proteomic analyses
| PRJNA925003 | ENA
Project description:Genotypic and phenotypic diversity of the multidrug-resistant Mycobacterium tuberculosis strains from eastern India
Project description:The alarming increase in antimicrobial resistance (AMR) will soon limit treatment options for even routine infections, especially those caused by Gram-negative bacteria such as Acinetobacter baumannii. Here, we report a two-pronged approach to identify new vulnerabilities in such pathogens. Staring from diphenyleneiodonium (dPI) salts, which are compounds that have moderate antimicrobial activity against Gram-positive pathogens, we synthesized a focused heterocyclic library and report a new analogue that has much higher inhibitory potency against multidrug-resistant Acinetobacter baumannii and excellent efficacy in reduction of bacterial burden in a mouse neutropenic thigh infection model. The lead compound was also found to synergize with aminoglycosides, which are routinely used in the treatment of such infections in humans. Further, we synthesized an alkyne containing probe and using gel and mass spectrometry base chemoproteomics platforms, we identified proteins that have redox cofactors as putative targets for this class of compounds. Additionally, we also demonstrate that the modification of proteins is covalent and through a cysteine residue. Together, using complementary chemical biology approaches, new vulnerabilities in Gram-negative pathogens were identified that would help address a burgeoning global problem of AMR.
Project description:<p>The study of antimicrobial resistance (AMR) in infectious diarrhea has generally been limited to cultivation, antimicrobial susceptibility testing and targeted PCR assays. When individual strains of significance are identified, whole genome shotgun (WGS) sequencing of important clones and clades is performed. Genes that encode resistance to antibiotics have been detected in environmental, insect, human and animal metagenomes and are known as "resistomes". While metagenomic datasets have been mined to characterize the healthy human gut resistome in the Human Microbiome Project and MetaHIT and in a Yanomani Amerindian cohort, directed metagenomic sequencing has not been used to examine the epidemiology of AMR. Especially in developing countries where sanitation is poor, diarrhea and enteric pathogens likely serve to disseminate antibiotic resistance elements of clinical significance. Unregulated use of antibiotics further exacerbates the problem by selection for acquisition of resistance. This is exemplified by recent reports of multiple antibiotic resistance in Shigella strains in India, in Escherichia coli in India and Pakistan, and in nontyphoidal Salmonella (NTS) in South-East Asia. We propose to use deep metagenomic sequencing and genome level assembly to study the epidemiology of AMR in stools of children suffering from diarrhea. Here the epidemiology component will be surveillance and analysis of the microbial composition (to the bacterial species/strain level where possible) and its constituent antimicrobial resistance genetic elements (such as plasmids, integrons, transposons and other mobile genetic elements, or MGEs) in samples from a cohort where diarrhea is prevalent and antibiotic exposure is endemic. The goal will be to assess whether consortia of specific mobile antimicrobial resistance elements associate with species/strains and whether their presence is enhanced or amplified in diarrheal microbiomes and in the presence of antibiotic exposure. This work could potentially identify clonal complexes of organisms and MGEs with enhanced resistance and the potential to transfer this resistance to other enteric pathogens.</p> <p>We have performed WGS, metagenomic assembly and gene/protein mapping to examine and characterize the types of AMR genes and transfer elements (transposons, integrons, bacteriophage, plasmids) and their distribution in bacterial species and strains assembled from DNA isolated from diarrheal and non-diarrheal stools. The samples were acquired from a cohort of pediatric patients and controls from Colombia, South America where antibiotic use is prevalent. As a control, the distribution and abundance of AMR genes can be compared to published studies where resistome gene lists from healthy cohort sequences were compiled. Our approach is more epidemiologic in nature, as we plan to identify and catalogue antimicrobial elements on MGEs capable of spread through a local population and further we will, where possible, link mobile antimicrobial resistance elements with specific strains within the population.</p>
Project description:There is an urgent need for novel antibiotics against carbapenem and 3rd generation cephalosporin-resistant Gram-negative pathogens, for which the last-resort antibiotics have lost most of their efficacy. We describe here a novel class of synthetic antibiotics that was inspired from natural product-derived scaffolds. The antibiotics have an unprecedented mechanism of action, which targets the main component (BamA) of the Bam folding machinery required for folding and insertion of ß-barrel proteins into the outer membrane of Gram-negative bacteria. This OMPTA (outer membrane protein-targeting antibiotic) class shows potent activity against multidrug-resistant Gram-negative ESKAPE pathogens and overcomes colistin-resistance both in vitro and in vivo. A clinical candidate has the potential to address life threatening Gram-negative infections with high unmet medical need.
2020-02-04 | MSV000084899 | MassIVE
Project description:Decoding Acinetobacter pittii: Unveiling Phenotypic and Genotypic Traits in Six Isolates
Project description:The race to combat antibiotic resistance and develop novel therapies has triggered studies on novel metal-based formulations. Silver remains a strong candidate since ancient times due to its multimodal and broad-spectrum activity against bacterial and fungal pathogens. N-heterocyclic carbene (NHC) complexes coordinate transition metals to generate a broad range of anticancer and/or antimicrobial agents with ongoing efforts being made to enhance lipophilicity and drug stability. The lead silver(I) acetate complex, 1,3-dibenzyl-4,5-diphenylimidazol-2-ylidene (NHC*) (SBC3) synthesised by the Tacke group has previously demonstrated promising growth and biofilm-inhibiting properties. As an extension of this, we examined the responses of two structurally different bacteria to SBC3 using label-free quantitative proteomic analysis. Multidrug resistant Pseudomonas aeruginosa (Gram-negative) and Staphylococcus aureus (Gram-positive) are associated with chronic wound infections and Cystic Fibrosis lung colonisation where co-infection often exacerbates disease. SBC3 increased the abundance of alginate biosynthesis, secretion system and drug detoxification proteins in P. aeruginosa whilst a multitude of pathways including anaerobic respiration, twitching motility, and ABC transport were decreased. This contrasted with affected pathways in S. aureus such as increased DNA replication/repair and cell redox homeostasis and decreased protein synthesis, lipoylation, glucose metabolism. Increased abundance of cell wall/membrane proteins were indicative of the structural damage induced by SBC3 to both cell types. These findings show the potential broad applications of SBC3 in treating Gram-positive and Gram-negative bacteria.