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Antibiotic Efflux

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https://www.readbyqxmd.com/read/29243909/optimization-of-coad-inhibitors-against-gram-negative-organisms-through-targeted-metabolomics
#1
Christopher M Rath, Bret M Benton, Javier De Vicente, Joseph E Drumm, Mei Geng, Cindy Li, Robert J Moreau, Xiaoyu Shen, Colin K Skepper, Micah Steffek, Kenneth Takeoka, Lisha Wang, Jun-Rong Wei, Wenjian Xu, Qiong Zhang, Brian Y Feng
Drug-resistant Gram-negative bacteria are of increasing concern worldwide. Novel antibiotics are needed, but their development is complicated by the requirement to simultaneously optimize molecules for target affinity and cellular potency, which can result in divergent structure-activity relationships (SARs). These challenges were exemplified during our attempts to optimize CoaD inhibitors identified through a biochemical screen. To facilitate lead optimization, we developed mass spectroscopy assays based on the hypothesis that levels of CoA metabolites would reflect the cellular enzymatic activity of CoaD...
December 15, 2017: ACS Infectious Diseases
https://www.readbyqxmd.com/read/29236663/-antibiotic-transport-and-membrane-permeability-new-insights-to-fight-bacterial-resistance
#2
Jean-Marie Pagès
A main challenge in medicinal chemistry is to determine the parameters modulating the in cellulo drug concentration needed for a therapeutic action. In Gram-negative antibacterial research, the concern is to evaluate the antibiotic permeation across the outer and inner membranes, that delineate the periplasm surrounding the bacterial cytoplasm. Passing through the membrane barrier to reach the inhibitory concentration inside the bacterium is the first pivotal step for antibiotics. The research and the development of new antimicrobials mostly rely on their capacity to reach critical concentrations in the vicinity of their intracellular target...
2017: Biologie Aujourd'hui
https://www.readbyqxmd.com/read/29235508/genetic-adaptation-of-microbial-populations-present-in-high-intensity-catfish-production-systems-with-therapeutic-oxytetracycline-treatment
#3
Qifan Zeng, Xiangli Tian, Luxin Wang
Microbial communities that are present in aquaculture production systems play significant roles in degrading organic matter, controlling diseases, and formation of antibiotic resistance. It is important to understand the diversity and abundance of microbial communities and their genetic adaptations associated with environmental physical and chemical changes. Here we collected water and sediment samples from a high-intensity catfish production system and its original water reservoir. The metagenomic analysis showed that Proteobacteria, Actinobacteria, Bacteroidetes, Cyanobacteria, and Firmicutes were the top five phyla identified from all samples...
December 13, 2017: Scientific Reports
https://www.readbyqxmd.com/read/29234497/insertional-inactivation-of-oprd-in-carbapenem-resistant-pseudomonas-aeruginosa-strains-isolated-from-burn-patients-in-tehran-iran
#4
A Shariati, T Azimi, A Ardebili, A S Chirani, A Bahramian, A Pormohammad, M Sadredinamin, S Erfanimanesh, N Bostanghadiri, S Shams, A Hashemi
In this study, we report the insertion sequence ISPpu21 in the oprD porin gene of carbapenem-resistant Pseudomonas aeruginosa isolates from burn patients in Tehran, Iran. Antibiotic susceptibility tests for P. aeruginosa isolates were determined. Production of metallo-β-lactamases (MBLs) and carbapenemase was evaluated and the β-lactamase-encoding and aminoglycoside-modifying enzyme genes were investigated by PCR and sequencing methods. The mRNA transcription level of oprD and mex efflux pump genes were evaluated by real-time PCR...
January 2018: New Microbes and New Infections
https://www.readbyqxmd.com/read/29233776/bovine-mastitis-an-appraisal-of-its-alternative-herbal-cure
#5
REVIEW
Saleem Mushtaq, Aabid Manzoor Shah, Aiyatullah Shah, Sajad Ahmad Lone, Aehtesham Hussain, Qazi Parvaiz Hassan, Md Niamat Ali
Bovine mastitis is globally recognised as the most common and costly disease affecting dairy herds. The disease causes huge financial losses to dairy industries by reduced yield and milk quality, deaths and culling of affected cows and also by associated treatment costs. The disease occurs due to invasion of the mammary glands by pathogenic bacteria followed by their multiplication in the milk producing tissues. The most common treatment method available against bovine mastitis is the intra-mammary infusion of antibiotics...
December 9, 2017: Microbial Pathogenesis
https://www.readbyqxmd.com/read/29224710/spm-1-producing-pseudomonas-aeruginosa-st277-clone-recovered-from-microbiota-of-migratory-birds
#6
Willames M B S Martins, Ana Clara Narciso, Rodrigo Cayô, Stéfanie Vanessa Santos, Lorena C C Fehlberg, Patrícia Locosque Ramos, João Batista da Cruz, Ana Cristina Gales
The production of São Paulo metallo-β-lactamase (SPM-1) is the most common carbapenem resistance mechanism detected among multidrug-resistant Pseudomonas aeruginosa clinical isolates in Brazil. Dissemination of SPM-1-producing P. aeruginosa has been restricted to the nosocomial settings, with sporadic reports of environmental isolates due to contamination by hospital sewage. Herein, we described the detection and molecular characterization of SPM-1-producing P. aeruginosa recovered from the microbiota of migratory birds in Brazil...
November 10, 2017: Diagnostic Microbiology and Infectious Disease
https://www.readbyqxmd.com/read/29220791/design-synthesis-and-biological-activity-evaluation-of-novel-4-subtituted-2-naphthamide-derivatives-as-acrb-inhibitors
#7
Yinhu Wang, Rumana Mowla, Shengli Ji, Liwei Guo, Miguel A De Barros Lopes, Chaobin Jin, Di Song, Shutao Ma, Henrietta Venter
A novel series of 4-substituted 2-naphthamide derivatives were designed, synthesized and evaluated for their biological activity. In particular, the ability of the compounds to potentiate the action of antibiotics, to inhibit Nile Red efflux and to target AcrB specifically was investigated. The results indicated that most of the 4-substituted 2-naphthamide derivatives were able to synergize with the antibiotics tested, and inhibit Nile Red efflux by AcrB in the resistant phenotype. Subsequent exclusion of compounds with off target effects such as outer- or inner membrane permeabilization identified compounds 7c, 7g, 12c, 12i and 13g as efflux pump inhibitors (EPIs)...
December 5, 2017: European Journal of Medicinal Chemistry
https://www.readbyqxmd.com/read/29213101/modulation-of-the-neisseria-gonorrhoeae-drug-efflux-conduit-mtre
#8
Giulia Tamburrino, Salomé Llabrés, Owen N Vickery, Samantha J Pitt, Ulrich Zachariae
Widespread antibiotic resistance, especially of Gram-negative bacteria, has become a severe concern for human health. Tripartite efflux pumps are one of the major contributors to resistance in Gram-negative pathogens, by efficiently expelling a broad spectrum of antibiotics from the organism. In Neisseria gonorrhoeae, one of the first bacteria for which pan-resistance has been reported, the most expressed efflux complex is MtrCDE. Here we present the electrophysiological characterisation of the outer membrane component MtrE and the membrane fusion protein MtrC, obtained by a combination of planar lipid bilayer recordings and in silico techniques...
December 6, 2017: Scientific Reports
https://www.readbyqxmd.com/read/29210342/antibiotics-potentiating-potential-of-catharanthine-against-superbug-pseudomonas-aeruginosa
#9
Gaurav Raj Dwivedi, Rekha Tyagi, Sanchita Gupta, Shubhandra Tripathi, Sanghamitra Pati, Santosh K Srivastava, Mahendra P Darokar, Ashok Sharma
Multidrug resistance (MDR) put an alarming situation like preantibiotic era which compels us to invigorate the basic science of anti-infective chemotherapy. Hence the drug resistant genes/proteins were explored as promising drug targets. Keeping this thing in mind, proteome of Pseudomonas aeruginosa PA01 was explored, which resulted in the identification of tripartite protein complexes (MexA, MexB and OprM) as promising drug target for the screening of natural and synthetic inhibitors. The purpose of present investigation was to explore the drug resistance reversal potential mechanism of catharanthine isolated from the leaves of Catharanthus roseous...
December 6, 2017: Journal of Biomolecular Structure & Dynamics
https://www.readbyqxmd.com/read/29209085/integrated-genomic-and-proteomic-analyses-of-high-level-chloramphenicol-resistance-in-campylobacter-jejuni
#10
Hui Li, Yingyu Wang, Qin Fu, Yang Wang, Xiaowei Li, Congming Wu, Zhangqi Shen, Qijing Zhang, Peibin Qin, Jianzhong Shen, Xi Xia
Campylobacter jejuni is a major zoonotic pathogen, and its resistance to antibiotics is of great concern for public health. However, few studies have investigated the global changes of the entire organism with respect to antibiotic resistance. Here, we provide mechanistic insights into high-level resistance to chloramphenicol in C. jejuni, using integrated genomic and proteomic analyses. We identified 27 single nucleotide polymorphisms (SNPs) as well as an efflux pump cmeB mutation that conferred modest resistance...
December 5, 2017: Scientific Reports
https://www.readbyqxmd.com/read/29208490/fluorescence-enlightens-rnd-pump-activity-and-the-intrabacterial-concentration-of-antibiotics
#11
Muriel Masi, Estelle Dumont, Julia Vergalli, Jelena Pajovic, Matthieu Réfrégiers, Jean-Marie Pagès
To understand antibiotic resistance in Gram-negative bacteria, a key point is to investigate antibiotic accumulation, which is defined by influx and efflux. Several methods exist to evaluate membrane permeability and efflux pump activity, but they present disadvantages and limitations. An optimized spectrofluorimetric method using intrinsic tryptophan fluorescence as an internal standard, as well as a complementary microfluorimetric assay following time-course accumulation in intact individual cells, have been developed...
December 2, 2017: Research in Microbiology
https://www.readbyqxmd.com/read/29208359/aminoguanidine-hydrazones-agh-s-as-modulators-of-norfloxacin-resistance-in-staphylococcus-aureus-that-overexpress-nora-efflux-pump
#12
Natalina Dantas, Thiago Mendonça de Aquino, João Xavier de Araújo-Júnior, Edeildo da Silva-Júnior, Ednaldo Almeida Gomes, Antoniel Augustos Severo Gomes, José Pinto Siqueira-Júnior, Francisco Jaime Bezerra Mendonça Junior
One of the promising fields for improving the effectiveness of antimicrobial agents is their combination with efflux pump inhibitors (EPIs), which besides expanding the use of existing antibiotics. The goal of this research was to evaluate a series of aminoguanidine hydrazones (AGH's, 1-19) as antibacterial agents and NorA efflux pump inhibitors in Staphylococcus aureus strain SA-1199B. Molecular modeling and docking studies were also performed in order to explain at the molecular level the interactions of the compounds with the generated NorA efflux pump model...
December 2, 2017: Chemico-biological Interactions
https://www.readbyqxmd.com/read/29206128/conformational-study-of-z-5-4-chlorobenzylidene-2-4-2-hydroxyethyl-piperazin-1-yl-3h-imidazol-4-5h-one-in-different-environments-insight-into-the-structural-properties-of-bacterial-efflux-pump-inhibitors
#13
Ewa Żesławska, Wojciech Nitek, Jadwiga Handzlik
The 2-amine derivatives of 5-arylidene-3H-imidazol-4(5H)-one are a new class of bacterial efflux pump inhibitors, the chemical compounds that are able to restore antibiotic efficacy against multidrug resistant bacteria. 5-Arylidene-3H-imidazol-4(5H)-ones with a piperazine ring at position 2 reverse the mechanisms of multidrug resistance (MDR) of the particularly dangerous Gram-negative bacteria E. coli by inhibition of the efflux pump AcrA/AcrB/TolC (a main multidrug resistance mechanism in Gram-negative bacteria, consisting of a membrane fusion protein, AcrA, a Resistant-Nodulation-Division protein, AcrB, and an outer membrane factor, TolC)...
December 1, 2017: Acta Crystallographica. Section C, Structural Chemistry
https://www.readbyqxmd.com/read/29205266/amphiphilic-lysine-conjugated-to-tobramycin-synergizes-legacy-antibiotics-against-wild-type-and-multidrug-resistant-pseudomonas-aeruginosa
#14
Yinfeng Lyu, Ronald Domalaon, Xuan Yang, Frank Schweizer
Peptidomimetic modification is a common route of optimization for biologically active peptides. Previous studies in our group have shown that conjugation of amphiphilic tobramycin to other antibacterials enhance their latent outer membrane permeabilizing and efflux blocking activity toward Gram-negative pathogens including Pseudomonas aeruginosa. Herein, we describe the antimicrobial adjuvant properties of amphiphilic lysine ligated to tobramycin. The most potent amphiphilic lysine-tobramycin conjugate 3 potentiated the antibacterial efficacy of 8 clinically used antibiotics against wild type, multidrug- and extensively drug-resistant P...
December 4, 2017: Biopolymers
https://www.readbyqxmd.com/read/29204354/unusual-carbapenem-resistant-but-ceftriaxone-and-cefepime-susceptible-klebsiella-oxytoca-isolated-from-a-blood-culture-case-report-and-whole-genome-sequencing-investigation
#15
Shangxin Yang, Peera Hemarajata, Laura Shevy, Mario Maciariello, Karissa Culbreath, Karen Bush, Romney Humphries
A carbapenem resistant but ceftriaxone and cefepime susceptible Klebsiella oxytoca was isolated from the blood of a patient with polymicrobial bacteremia after 2 weeks of ertapenem treatment. Whole-genome sequencing identified no carbapenemase gene nor plasmid, but only blaOXY-2-8 gene with a mutation in the promoter that's been reported to increase its expression. Two other specific carbapenem resistance mechanisms including mutated porin genes and the AcrAB-TolC efflux system genes were also identified. Clinicians need to be aware of such unusual antibiogram and should not assume carbapenems are always broader spectrum antibiotics than expanded-spectrum cephalosporins...
2018: IDCases
https://www.readbyqxmd.com/read/29204271/genome-sequencing-and-analysis-of-the-first-spontaneous-nanosilver-resistant-bacterium-proteus-mirabilis-strain-scdr1
#16
Amr T M Saeb, Khalid A Al-Rubeaan, Mohamed Abouelhoda, Manojkumar Selvaraju, Hamsa T Tayeb
Background: P. mirabilis is a common uropathogenic bacterium that can cause major complications in patients with long-standing indwelling catheters or patients with urinary tract anomalies. In addition, P. mirabilis is a common cause of chronic osteomyelitis in Diabetic foot ulcer (DFU) patients. We isolated P. mirabilis SCDR1 from a Diabetic ulcer patient. We examined P. mirabilis SCDR1 levels of resistance against Nanosilver colloids, the commercial Nanosilver and silver containing bandages and commonly used antibiotics...
2017: Antimicrobial Resistance and Infection Control
https://www.readbyqxmd.com/read/29201106/expression-of-tolc-and-organic-solvent-tolerance-of-escherichia-coli-ciprofloxacin-resistant-mutants
#17
Razieh Pourahmad Jaktaji, Farzaneh Zargampoor
AcrAB-TolC is a major efflux pump in Escherichia coli. It was reported that tolC is overexpressed and involves in improving the organic solvent tolerance level in Escherichia colimarR mutants that are resistant to several antibiotics, such as ciprofloxacin. Low and intermediate levels resistance did not improve organic solvent tolerance. Thus, it was decided to measure tolC expression and organic solvent tolerance in high level ciprofloxacin resistant mutants. tolC expression was measured by real time PCR and organic solvent tolerance assay was conducted by counting bacterial colonies on LBGMg agar...
2017: Iranian Journal of Pharmaceutical Research: IJPR
https://www.readbyqxmd.com/read/29201017/characterization-of-metagenomes-in-urban-aquatic-compartments-reveals-high-prevalence-of-clinically-relevant-antibiotic-resistance-genes-in-wastewaters
#18
Charmaine Ng, Martin Tay, Boonfei Tan, Thai-Hoang Le, Laurence Haller, Hongjie Chen, Tse H Koh, Timothy M S Barkham, Karina Y-H Gin
The dissemination of antimicrobial resistance (AMR) is an escalating problem and a threat to public health. Comparative metagenomics was used to investigate the occurrence of antibiotic resistant genes (ARGs) in wastewater and urban surface water environments in Singapore. Hospital and municipal wastewater (n = 6) were found to have higher diversity and average abundance of ARGs (303 ARG subtypes, 197,816 x/Gb) compared to treated wastewater effluent (n = 2, 58 ARG subtypes, 2,692 x/Gb) and surface water (n = 5, 35 subtypes, 7,985 x/Gb)...
2017: Frontiers in Microbiology
https://www.readbyqxmd.com/read/29199856/antimicrobial-activity-of-six-essential-oils-against-burkholderia-cepacia-complex-insights-into-mechanism-s-of-action
#19
Elena Perrin, Valentina Maggini, Isabel Maida, Eugenia Gallo, Katia Lombardo, Maria Pia Madarena, Silvia Buroni, Viola Camilla Scoffone, Fabio Firenzuoli, Alessio Mengoni, Renato Fani
AIM: To investigate the activity and mechanisms of action of six essential oils (EOs) against Burkholderia cepacia complex, opportunistic human pathogens highly resistant to antibiotics. MATERIALS & METHODS: Minimal inhibitory concentration of EOs alone, plus antibiotics or efflux pump inhibitors was determined. RESULTS: Origanum vulgare, Thymus vulgaris and Eugenia caryophyllata EOs resulted to be more active than the other EOs. EOs did not enhance antibiotic activity against the model strain B...
December 4, 2017: Future Microbiology
https://www.readbyqxmd.com/read/29194931/antibiotic-resistome-in-a-large-scale-healthy-human-gut-microbiota-deciphered-by-metagenomic-and-network-analyses
#20
Jie Feng, Bing Li, Xiaotao Jiang, Ying Yang, George F Wells, Tong Zhang, Xiaoyan Li
The human gut microbiota is an important reservoir of antibiotic resistance genes (ARGs). A metagenomic approach and network analysis were used to establish a comprehensive antibiotic resistome catalog and to obtain co-occurrence patterns between ARGs and microbial taxa in fecal samples from 180 healthy individuals from 11 different countries. In total, 507 ARG subtypes belonging to 20 ARG types were detected with abundances ranging from 7.12 × 10-7 to 2.72 × 10-1 copy of ARG/copy of 16S-rRNA gene. Tetracycline, multidrug, macrolide-lincosamide-streptogramin, bacitracin, vancomycin, beta-lactam and aminoglycoside resistance genes were the top seven most abundant ARG types...
December 1, 2017: Environmental Microbiology
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