Switching Residues: A Platform for the Synthesis of Fidaxomicin Antibiotics.

Peripheral modification is often the main approach to optimize natural products for improved biological activity or desired physicochemical properties. This procedure inevitably increases molecular weight, often accompanied by undesired increased lipophilicity. Removing structural elements from natural products is not always tolerated.

Durlobactam to boost the clinical utility of standard of care β-lactams against lung disease.

β-Lactams present several desirable pharmacodynamic features leading to the rapid eradication of many bacterial pathogens. Imipenem (IPM) and cefoxitin (FOX) are injectable β-lactams recommended during the intensive treatment phase of pulmonary infections caused by (Mab). However, their potency against Mab is many-fold lower than against Gram-positive and Gram-negative pathogens for which they were optimized, putting into question their clinical utility.

Synthesis and antibacterial action of 3',6'-disubstituted spectinomycins.

Spectinomycin is an aminocyclitol antibiotic with a unique ribosomal binding site. Prior synthetic modifications of spectinomycin have enhanced potency and antibacterial spectrum through addition at the 6'-position to produce trospectomycin and to the 3'-position to produce spectinamides and aminomethyl spectinomycins. This study focused on the design, synthesis, and evaluation of three 3',6'-disubstituted spectinomycin analogs: trospectinamide, N-benzyl linked aminomethyl, and N-ethylene linked aminomethyl trospectomycins.

Development of 2nd generation aminomethyl spectinomycins that overcome native efflux in abscessus.

(), a nontuberculous mycobacterial (NTM) species, is an emerging pathogen with high intrinsic drug resistance. Current standard-of-care therapy results in poor outcomes, demonstrating the urgent need to develop effective antimycobacterial regimens. Through synthetic modification of spectinomycin (SPC), we have identified a distinct structural subclass of N-ethylene linked aminomethyl SPCs (eAmSPCs) that are up to 64-fold more potent against over the parent SPC.

Phenolic Substitution in Fidaxomicin: A Semisynthetic Approach to Antibiotic Activity Across Species.

Fidaxomicin (Fdx) is a natural product antibiotic with potent activity against Clostridioides difficile and other Gram-positive bacteria such as Mycobacterium tuberculosis. Only a few Fdx derivatives have been synthesized and examined for their biological activity in the 50 years since its discovery. Fdx has a well-studied mechanism of action, namely inhibition of the bacterial RNA polymerase.

Bedaquiline and Clofazimine Susceptibility Testing in Mycobacterium abscessus.

Bedaquiline and clofazimine are increasingly used to treat infections with Mycobacterium abscessus. We determined distributions of MICs by broth microdilution for bedaquiline and clofazimine for 61 M. abscessus clinical isolates using different media and incubation times.

Mortality from drug-resistant tuberculosis in high-burden countries comparing routine drug susceptibility testing with whole-genome sequencing: a multicentre cohort study.

Background: Drug resistance threatens global tuberculosis control. We aimed to examine mortality in patients with tuberculosis from high-burden countries, according to concordance or discordance of results from drug susceptibility testing done locally and whole-genome sequencing (WGS).

Methods: In this multicentre cohort study, we collected pulmonary isolates and clinical data from individuals with tuberculosis from antiretroviral therapy programmes and tuberculosis clinics in Côte d'Ivoire, Democratic Republic of the Congo, Kenya, Nigeria, Peru, South Africa, and Thailand, stratified by HIV status and drug resistance.

Photochemically-Mediated Inflammation and Cross-Presentation of BCG Proteins Stimulates Strong CD4 and CD8 T-Cell Responses in Mice.

Conventional vaccines are very efficient in the prevention of bacterial infections caused by extracellular pathogens due to effective stimulation of pathogen-specific antibodies. In contrast, considering that intracellular surveillance by antibodies is not possible, they are typically less effective in preventing or treating infections caused by intracellular pathogens such as . The objective of the current study was to use so-called photochemical internalization (PCI) to deliver a live bacterial vaccine to the cytosol of antigen-presenting cells (APCs) for the purpose of stimulating major histocompatibility complex (MHC) I-restricted CD8 T-cell responses.

Apramycin Overcomes the Inherent Lack of Antimicrobial Bactericidal Activity in Mycobacterium abscessus.

Antibiotic therapy of infections caused by the emerging pathogen Mycobacterium abscessus is challenging due to the organism's inherent resistance to clinically available antimicrobials. The low bactericidal potency of currently available treatment regimens is of concern and testifies to the poor therapeutic outcomes for pulmonary M. abscessus infections.

Aquimarins, Peptide Antibiotics with Amino-Modified C-Termini from a Sponge-Derived Aquimarina sp. Bacterium.

Genome mining and bioactivity studies suggested the sponge-derived bacterium Aquimarina sp. Aq135 as a producer of new antibiotics. Activity-guided isolation identified antibacterial peptides, named aquimarins, featuring a new scaffold with an unusual C-terminal amino group and chlorine moieties.

Phosphoribosyltransferase Promotes Bacterial Survival in Macrophages by Inducing Histone Hypermethylation in Autophagy-Related Genes.

inhibits autophagy to promote its survival in host cells. However, the molecular mechanisms by which inhibits autophagy are poorly understood. Here, we report a previously unknown mechanism in which phosphoribosyltransferase (PRT) inhibits autophagy in an mTOR, negative regulator of autophagy, independent manner by inducing histone hypermethylation (H3K9me2/3) at the and promoters by activating p38-MAPK- and EHMT2 methyltransferase-dependent signaling pathways.

Novel fidaxomicin antibiotics through site-selective catalysis.

Fidaxomicin (FDX) is a marketed antibiotic for the treatment of Clostridioides difficile infections (CDI). Fidaxomicin displays antibacterial properties against many Gram-positive bacteria, yet the application of this antibiotic is currently limited to treatment of CDI. Semisynthetic modifications present a promising strategy to improve its pharmacokinetic properties and also circumvent resistance development by broadening the structural diversity of the derivatives.

Drug susceptibility distributions of and other non-tuberculous mycobacteria.

Recent outbreaks of cardiac surgery-associated infections have highlighted the importance of species differentiation within the complex and pointed to a lack of antibiotic susceptibility data for Using the MGIT 960/EpiCenter TB eXiST platform, we have determined antibiotic susceptibility patterns of 48 clinical isolates and 139 other non-tuberculous mycobacteria including 119 members of the complex and 20 towards clofazimine and other drugs used to treat infections with slowly growing nontuberculous mycobacteria (NTM). MIC, MIC and tentative epidemiological cutoff (ECOFF) values for clofazimine were 0.5 mg/L, 1 mg/L and 2 mg/L for Comparable values were observed for other complex members, lower MIC (≤0.

Semisynthetic Analogs of the Antibiotic Fidaxomicin-Design, Synthesis, and Biological Evaluation.

The glycoslated macrocyclic antibiotic fidaxomicin (, tiacumicin B, lipiarmycin A3) displays good to excellent activity against Gram-positive bacteria and was approved for the treatment of infections (CDI). Among the main limitations for this compound, its low water solubility impacts further clinical uses. We report on the synthesis of new fidaxomicin derivatives based on structural design and utilizing an operationally simple one-step protecting group-free preparative approach from the natural product.

Natural Polymorphisms in Mycobacterium tuberculosis Conferring Resistance to Delamanid in Drug-Naive Patients.

Mutations in the genes of the F signaling pathway of complex, including , , , , , and , can lead to delamanid resistance. We searched for such mutations among 129 strains from Asia, South America, and Africa using whole-genome sequencing; 70 (54%) strains had at least one mutation in one of the genes. For 10 strains with mutations, we determined the MIC of delamanid.

Identification of novel scaffolds targeting Mycobacterium tuberculosis.

Drug resistance in Mycobacterium tuberculosis is relentlessly progressing while only a handful of novel drug candidates are developed. Here we describe a GFP-based high-throughput screening of 386,496 diverse compounds to identify putative tuberculosis drug candidates. In an exploratory analysis of the model organism M.

BATF3-dependent dendritic cells drive both effector and regulatory T-cell responses in bacterially infected tissues.

The gastric lamina propria of mice that have been experimentally infected with the pathobiont Helicobacter pylori hosts a dense network of myeloid cells that includes BATF3-dependent CD103+ dendritic cells (DCs). We show here that CD103+ DCs are strictly required for gastric Th1 responses to H. pylori and for H.

Increased drug permeability of a stiffened mycobacterial outer membrane in cells lacking MFS transporter Rv1410 and lipoprotein LprG.

The major facilitator superfamily transporter Rv1410 and the lipoprotein LprG (Rv1411) are encoded by a conserved two-gene operon and contribute to virulence in Mycobacterium tuberculosis. Rv1410 was originally postulated to function as a drug efflux pump, but recent studies suggested that Rv1410 and LprG work in concert to insert triacylglycerides and lipoarabinomannans into the outer membrane. Here, we conducted microscopic analyses of Mycobacterium smegmatis lacking the operon and observed a cell separation defect, while surface rigidity measured by atomic force microscopy was found to be increased.

Whole-Genome Sequencing for Drug Resistance Profile Prediction in .

Whole-genome sequencing allows rapid detection of drug-resistant isolates. However, the availability of high-quality data linking quantitative phenotypic drug susceptibility testing (DST) and genomic data have thus far been limited. We determined drug resistance profiles of 176 genetically diverse clinical isolates from the Democratic Republic of the Congo, Ivory Coast, Peru, Thailand, and Switzerland by quantitative phenotypic DST for 11 antituberculous drugs using the BD Bactec MGIT 960 system and 7H10 agar dilution to generate a cross-validated phenotypic DST readout.

The Role of Antibiotic-Target-Modifying and Antibiotic-Modifying Enzymes in Drug Resistance.

The incidence and prevalence of non-tuberculous mycobacterial (NTM) infections have been increasing worldwide and lately led to an emerging public health problem. Among rapidly growing NTM, is the most pathogenic and drug resistant opportunistic germ, responsible for disease manifestations ranging from "curable" skin infections to only "manageable" pulmonary disease. Challenges in treatment stem from the bacteria's high-level innate resistance and comprise long, costly and non-standardized administration of antimicrobial agents, poor treatment outcomes often related to adverse effects and drug toxicities, and high relapse rates.

A uniform cloning platform for mycobacterial genetics and protein production.

Molecular research on mycobacteria relies on a multitude of tools for the genetic manipulation of these clinically important bacteria. However, a uniform set of vectors allowing for standardized cloning procedures is not available. Here, we developed a versatile series of mycobacterial vectors for gene deletion, complementation and protein production and purification.