scholarly journals Lipoprotein Glycosylation by Protein-O-Mannosyltransferase (MAB_1122c) Contributes to Low Cell Envelope Permeability and Antibiotic Resistance of Mycobacterium abscessus

2017 ◽  
Vol 8 ◽  
Author(s):  
Katja Becker ◽  
Klara Haldimann ◽  
Petra Selchow ◽  
Lukas M. Reinau ◽  
Michael Dal Molin ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Cell Envelope ◽  
Mycobacterium Abscessus

scholarly journals A target engagement assay to assess uptake, potency and retention of antibiotics in living bacteria

2021 ◽  
Author(s):  
Rafael Couñago ◽  
Rebeka Fanti ◽  
Stanley Vasconcelos ◽  
Carolina Catta-Preta ◽  
Jaryd Sullivan ◽  
...  
Keyword(s):  
Cell Envelope ◽  
Molecular Targets ◽  
Mycobacterium Abscessus ◽  
Gram Negative Bacteria ◽  
Human Pathogen ◽  
Binding Parameters ◽  
Target Engagement ◽  
Equilibrium And Kinetics ◽  
Live Bacteria ◽  
Target Activity

Abstract A major challenge in antibiotics drug discovery is to turn potent biochemical inhibitors of essential bacterial components into effective antimicrobials. This difficulty is underpinned by a lack of methods to investigate the physicochemical properties needed for candidate antibiotics to permeate the bacterial cell envelope and avoid clearance by the action of bacterial efflux pumps. To address these issues, here we used a target engagement assay to measure the equilibrium and kinetics binding parameters of antibiotics to their molecular targets in live bacteria. We validated this approach for a known antibiotic target, dihydrofolate reductase, using the Gram-negative bacteria Escherichia coli and the emerging human pathogen Mycobacterium abscessus. We expect the use of similar target engagement assays to expedite the discovery and progression of novel, cell-permeable antibiotics with on-target activity.

scholarly journals A genome-scale antibiotic screen in Serratia marcescens identifies YdgH as a conserved modifier of cephalosporin and detergent susceptibility

2021 ◽  
Author(s):  
Jacob E. Lazarus ◽  
Alyson R. Warr ◽  
Kathleen A. Westervelt ◽  
David C. Hooper ◽  
Matthew K. Waldor
Keyword(s):  
Antibiotic Resistance ◽  
Serratia Marcescens ◽  
Cell Envelope ◽  
Single Gene ◽  
Intrinsic Resistance ◽  
Minimal Inhibitory Concentrations ◽  
Transposon Insertion ◽  
A Genome ◽  
Before And After ◽  
Invasive Infections

Serratia marcescens , a member of the order Enterobacterales, is adept at colonizing healthcare environments and an important cause of invasive infections. Antibiotic resistance is a daunting problem in S. marcescens because in addition to plasmid-mediated mechanisms, most isolates have considerable intrinsic resistance to multiple antibiotic classes. To discover endogenous modifiers of antibiotic susceptibility in S. marcescens , a high-density transposon insertion library was subjected to sub-minimal inhibitory concentrations of two cephalosporins, cefoxitin and cefepime, as well as the fluoroquinolone ciprofloxacin. Comparisons of transposon insertion abundance before and after antibiotic exposure identified hundreds of potential modifiers of susceptibility to these agents. Using single gene deletions, we validated several candidate modifiers of cefoxitin susceptibility and chose ydgH , a gene of unknown function, for further characterization. In addition to cefoxitin, deletion of y dgH in S. marcescens resulted in decreased susceptibility to multiple 3 rd generation cephalosporins, and in contrast, to increased susceptibility to both cationic and anionic detergents. YdgH is highly conserved throughout the Enterobacterales, and we observed similar phenotypes in Escherichia coli O157:H7 and Enterobacter cloacae mutants. YdgH is predicted to localize to the periplasm and we speculate that it may be involved there in cell envelope homeostasis. Collectively, our findings provide insight into chromosomal mediators of antibiotic resistance in S. marcescens and will serve as a resource for further investigations of this important pathogen.

Core oligosaccharide portion of lipopolysaccharide plays important roles on multiple antibiotic resistance in Escherichia coli

2021 ◽  
Author(s):  
Jianli Wang ◽  
Wenjian Ma ◽  
Yu Fang ◽  
Hao Liang ◽  
Huiting Yang ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Antibiotic Resistance ◽  
Cell Envelope ◽  
Gene Clusters ◽  
Gram Negative Bacteria ◽  
Multiple Antibiotic Resistance ◽  
Core Oligosaccharide ◽  
Gram Negative ◽  
The Core ◽  
K 12

Gram-negative bacteria are intrinsically resistant to antibiotics due to the presence of the cell envelope, but mechanisms are still not fully understood. In this study, a series of mutants that lack one or more major components associated with the cell envelope were constructed from Escherichia coli K-12 W3110. WJW02 can only synthesize Kdo 2 -lipid A which lacks the core oligosaccharide portion of lipopolysaccharide. WJW04, WJW07 and WJW08 were constructed from WJW02 by deleting the gene clusters relevant to the biosynthesis of exopolysaccharide, flagella and fimbria, respectively. WJW09, WJW010 and WJW011 cells cannot synthesize exopolysaccharide, flagella and fimbria, respectively. Comparing to the wild type W3110, mutants WJW02, WJW04, WJW07 and WJW08 cells showed decreased resistance to more than 10 different antibacterial drugs, but not the mutants WJW09, WJW010 and WJW011. This indicates that the core oligosaccharide portion of lipopolysaccharide plays important roles on multiple antibiotic resistance in E. coli and the 1 st heptose in core oligosaccharide portion is critical. Furthermore, the removal of the core oligosaccharide of LPS leads to influences on cell wall morphology, cell phenotypes, porins, efflux systems, and the respond behaviors to antibiotic stimulation. The results demonstrated the important role of lipopolysaccharide on the antibiotic resistance of Gram-negative bacteria.

scholarly journals Evaluation of the GenoType NTM-DR assay performance for the identification and molecular detection of antibiotic resistance in Mycobacterium abscessus complex

PLoS ONE ◽  
2020 ◽  
Vol 15 (9) ◽  
pp. e0239146
Author(s):  
Nicolas Bouzinbi ◽  
Olivier Marcy ◽  
Thibault Bertolotti ◽  
Raphael Chiron ◽  
Pascale Bemer ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Molecular Detection ◽  
Mycobacterium Abscessus ◽  
Mycobacterium Abscessus Complex ◽  
Assay Performance

scholarly journals Induction of Daptomycin Tolerance in Enterococcus faecalis by Fatty Acid Combinations

2020 ◽  
Vol 86 (20) ◽  
Author(s):  
William Brewer ◽  
Johnathan Harrison ◽  
Holly E. Saito ◽  
Elizabeth M. Fozo
Keyword(s):  
Fatty Acids ◽  
Antibiotic Resistance ◽  
Fatty Acid ◽  
Stearic Acid ◽  
Enterococcus Faecalis ◽  
Cell Envelope ◽  
Negative Effects ◽  
Gram Positive ◽  
Bacterial Populations ◽  
Content Type

ABSTRACT Enterococcus faecalis is a Gram-positive bacterium that normally exists as an intestinal commensal in humans but is also a leading cause of nosocomial infections. Previous work noted that growth supplementation with serum induced tolerance to membrane-damaging agents, including the antibiotic daptomycin. Specific fatty acids found within serum could independently provide tolerance to daptomycin (protective fatty acids), yet some fatty acids found in serum did not and had negative effects on enterococcal physiology (nonprotective fatty acids). Here, we measured a wide array of physiological responses after supplementation with combinations of protective and nonprotective fatty acids to better understand how serum induces daptomycin tolerance. When cells were supplemented with either nonprotective fatty acid, palmitic acid, or stearic acid, there were marked defects in growth and morphology, but these defects were rescued upon supplementation with either protective fatty acid, oleic acid, or linoleic acid. Membrane fluidity decreased with growth in either palmitic or stearic acid alone but returned to basal levels when a protective fatty acid was supplied. Daptomycin tolerance could be induced if a protective fatty acid was provided with a nonprotective fatty acid, and some specific combinations protected as well as serum supplementation. While cell envelope charge has been associated with tolerance to daptomycin in other Gram-positive bacteria, we concluded that it does not correlate with the fatty acid-induced protection we observed. Based on these observations, we conclude that daptomycin tolerance by serum is driven by specific, protective fatty acids found within the fluid. IMPORTANCE With an increasing prevalence of antibiotic resistance in the clinic, we strive to understand more about microbial defensive mechanisms. A nongenetic tolerance to the antibiotic daptomycin was discovered in Enterococcus faecalis that results in the increased survival of bacterial populations after treatment with the drug. This tolerance mechanism likely synergizes with antibiotic resistance in the clinic. Given that this tolerance phenotype is induced by incorporation of fatty acids present in the host, it can be assumed that infections by this organism require a higher dose of antibiotic for successful eradication. The mixture of fatty acids in human fluids is quite diverse, with little understanding between the interplay of fatty acid combinations and the tolerance phenotype we observe. It is crucial to understand the effects of fatty acid combinations on E. faecalis physiology if we are to suppress the tolerance physiology in the clinic.

scholarly journals Mycobacterial HflX is a ribosome splitting factor that mediates antibiotic resistance

2019 ◽  
Vol 117 (1) ◽  
pp. 629-634 ◽  
Author(s):  
Paulami Rudra ◽  
Kelley R. Hurst-Hess ◽  
Katherine L. Cotten ◽  
Andrea Partida-Miranda ◽  
Pallavi Ghosh
Keyword(s):  
Antibiotic Resistance ◽  
Mycobacterium Smegmatis ◽  
Mycobacterium Abscessus ◽  
Macrolide Resistance ◽  
Gtp Hydrolysis ◽  
Ribosomal Subunits ◽  
Mutant Proteins ◽  
Splitting Factor

Antibiotic resistance in bacteria is typically conferred by proteins that function as efflux pumps or enzymes that modify either the drug or the antibiotic target. Here we report an unusual mechanism of resistance to macrolide-lincosamide antibiotics mediated by mycobacterial HflX, a conserved ribosome-associated GTPase. We show that deletion of thehflXgene in the pathogenicMycobacterium abscessus, as well as the nonpathogenicMycobacterium smegmatis, results in hypersensitivity to the macrolide-lincosamide class of antibiotics. Importantly, the level of resistance provided byMab_hflXis equivalent to that conferred byerm41, implying thathflXconstitutes a significant resistance determinant inM. abscessus. We demonstrate that mycobacterial HflX associates with the 50S ribosomal subunits in vivo and can dissociate purified 70S ribosomes in vitro, independent of GTP hydrolysis. The absence of HflX in aΔMs_hflXstrain also results in a significant accumulation of 70S ribosomes upon erythromycin exposure. Finally, a deletion of either the N-terminal or the C-terminal domain of HflX abrogates ribosome splitting and concomitantly abolishes the ability of mutant proteins to mediate antibiotic tolerance. Together, our results suggest a mechanism of macrolide-lincosamide resistance in which the mycobacterial HflX dissociates antibiotic-stalled ribosomes and rescues the bound mRNA. Given the widespread presence ofhflXgenes, we anticipate this as a generalized mechanism of macrolide resistance used by several bacteria.

β-lactam antibiotic selection of non-swarming mutants ofFlexibacter maritimus

1999 ◽  
Vol 45 (9) ◽  
pp. 786-790 ◽  
Author(s):  
Robert P Burchard
Keyword(s):  
Antibiotic Resistance ◽  
Cell Surface ◽  
Surface Properties ◽  
High Frequency ◽  
Cell Envelope ◽  
Antibiotic Selection ◽  
Cell Surface Properties ◽  
Lactam Antibiotic ◽  
Increased Sensitivity ◽  
Selection Of

Non-swarming mutants of Flexibacter maritimus appeared at high frequency on β-lactam antibiotic-containing medium. Among them were several phenotypes characterized by changes in cell surface properties and cell envelope proteins, in adhesion and in resistance to β-lactams, including increased sensitivity to these antibiotics.Key words: Flexibacter, gliding, adhesion, β-lactam, antibiotic resistance.

scholarly journals Chemical Genetic Interaction Profiling Reveals Determinants of Intrinsic Antibiotic Resistance in Mycobacterium tuberculosis

2017 ◽  
Vol 61 (12) ◽  
Author(s):  
Weizhen Xu ◽  
Michael A. DeJesus ◽  
Nadine Rücker ◽  
Curtis A. Engelhart ◽  
Meredith G. Wright ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Mycobacterium Tuberculosis ◽  
Antibiotic Susceptibility ◽  
Genetic Interaction ◽  
Cell Envelope ◽  
Mycolic Acid ◽  
Protein Characterization ◽  
Intrinsic Resistance ◽  
Content Type ◽  
Chemical Genetic

ABSTRACT Chemotherapy for tuberculosis (TB) is lengthy and could benefit from synergistic adjuvant therapeutics that enhance current and novel drug regimens. To identify genetic determinants of intrinsic antibiotic susceptibility in Mycobacterium tuberculosis, we applied a chemical genetic interaction (CGI) profiling approach. We screened a saturated transposon mutant library and identified mutants that exhibit altered fitness in the presence of partially inhibitory concentrations of rifampin, ethambutol, isoniazid, vancomycin, and meropenem, antibiotics with diverse mechanisms of action. This screen identified the M. tuberculosis cell envelope to be a major determinant of antibiotic susceptibility but did not yield mutants whose increase in susceptibility was due to transposon insertions in genes encoding efflux pumps. Intrinsic antibiotic resistance determinants affecting resistance to multiple antibiotics included the peptidoglycan-arabinogalactan ligase Lcp1, the mycolic acid synthase MmaA4, the protein translocase SecA2, the mannosyltransferase PimE, the cell envelope-associated protease CaeA/Hip1, and FecB, a putative iron dicitrate-binding protein. Characterization of a deletion mutant confirmed FecB to be involved in the intrinsic resistance to every antibiotic analyzed. In contrast to its predicted function, FecB was dispensable for growth in low-iron medium and instead functioned as a critical mediator of envelope integrity.

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