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efflux pump inhibition

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https://www.readbyqxmd.com/read/28549490/whole-genome-analysis-reveals-new-insights-into-macrolide-resistance-in-mycoplasma-pneumoniae
#1
Shao Li Li, Hong Mei Sun, Bao Li Zhu, Fei Liu, Han Qing Zhao
OBJECTIVE: Mutations in 23S rRNA gene are known to be associated with macrolide resistance in Mycoplasma pneumoniae (M. pneumoniae). However, these mutations alone do not fully explain the high resistance rates in Asia. The aim of this study was to investigate other possible mutations involved in macrolide resistance in M. pneumoniae. METHODS: The whole genomes of 10 clinical isolates of M. pneumoniae with macrolide resistance were sequenced by Illumina HiSeq2000 platform...
May 2017: Biomedical and Environmental Sciences: BES
https://www.readbyqxmd.com/read/28533185/the-small-molecule-iitr08027-restores-the-antibacterial-activity-of-fluoroquinolones-against-multidrug-resistant-acinetobacter-baumannii-by-efflux-inhibition
#2
Tapas Bhattacharyya, Atin Sharma, Jawed Akhter, Ranjana Pathania
Efflux pumps are one of the major determinants of multiple drug resistance. In this study, AbeM, a multidrug efflux pump in Acinetobacter baumannii, was cloned into a multicopy plasmid (pUC18) and was transformed into an efflux-deficient mutant of Escherichia coli (KAM32). The elevated resistance profile of the recombinant E. coli for ciprofloxacin was utilised to screen a small-molecule library of 8000 molecules to identify IITR08027, a small molecule that is not inhibitory on its own but that could potentiate the activity of ciprofloxacin...
May 19, 2017: International Journal of Antimicrobial Agents
https://www.readbyqxmd.com/read/28516003/mode-of-action-of-the-2-phenylquinoline-efflux-inhibitor-pqq4r-against-escherichia-coli
#3
Diana Machado, Laura Fernandes, Sofia S Costa, Rolando Cannalire, Giuseppe Manfroni, Oriana Tabarrini, Isabel Couto, Stefano Sabatini, Miguel Viveiros
Efflux pump inhibitors are of great interest since their use as adjuvants of bacterial chemotherapy can increase the intracellular concentrations of the antibiotics and assist in the battle against the rising of antibiotic-resistant bacteria. In this work, we have described the mode of action of the 2-phenylquinoline efflux inhibitor (4-(2-(piperazin-1-yl)ethoxy)-2-(4-propoxyphenyl) quinolone - PQQ4R), against Escherichia coli, by studding its efflux inhibitory ability, its synergistic activity in combination with antibiotics, and compared its effects with the inhibitors phenyl-arginine-β-naphthylamide (PAβN) and chlorpromazine (CPZ)...
2017: PeerJ
https://www.readbyqxmd.com/read/28506804/chloroquine-enhances-the-antimycobacterial-activity-of-isoniazid-and-pyrazinamide-by-reversing-inflammation-induced-macrophage-efflux
#4
U Matt, P Selchow, M Dal Molin, S Strommer, O Sharif, K Schilcher, F Andreoni, A Stenzinger, A S Zinkernagel, M Zeitlinger, P Sander, J Nemeth
Mycobacterium tuberculosis (MTB) is notorious for persisting within host macrophages. Efflux pumps decrease intracellular drug levels, thus fostering persistence of MTB during therapy. Isoniazid (INH) and pyrazinamide (PZA) are substrates of the efflux pump breast cancer resistance protein-1 (BCRP-1), which is inhibited by chloroquine (CQ). In this study, BCRP-1 was found to be expressed on macrophages of human origin and on foamy giant cells at the site of MTB infection. In the current in vitro study, interferon-gamma (IFNγ) increased the expression of BCRP-1 in macrophages derived from the human monocytic leukaemia cell line THP-1...
May 12, 2017: International Journal of Antimicrobial Agents
https://www.readbyqxmd.com/read/28504927/mechanisms-of-quinolone-action-and-resistance-where-do-we-stand
#5
Susana Correia, Patrícia Poeta, Michel Hébraud, José Luis Capelo, Gilberto Igrejas
Quinolone antibiotics represent one of the most important classes of anti-infective agents and, although still clinically valuable, their use has been compromised by the increasing emergence of resistant strains, which has become a prevalent clinical problem. Quinolones act by inhibiting the activity of DNA gyrase and topoisomerase IV - two essential bacterial enzymes that modulate the chromosomal supercoiling required for critical nucleic acid processes. The acquisition of quinolone resistance is recognized to be multifactorial and complex...
May 2017: Journal of Medical Microbiology
https://www.readbyqxmd.com/read/28496433/interplay-between-mutations-and-efflux-in-drug-resistant-clinical-isolates-of-mycobacterium-tuberculosis
#6
Diana Machado, Tatiane S Coelho, João Perdigão, Catarina Pereira, Isabel Couto, Isabel Portugal, Raquel De Abreu Maschmann, Daniela F Ramos, Andrea von Groll, Maria L R Rossetti, Pedro A Silva, Miguel Viveiros
Numerous studies show efflux as a universal bacterial mechanism contributing to antibiotic resistance and also that the activity of the antibiotics subject to efflux can be enhanced by the combined use of efflux inhibitors. Nevertheless, the contribution of efflux to the overall drug resistance levels of clinical isolates of Mycobacterium tuberculosis is poorly understood and still is ignored by many. Here, we evaluated the contribution of drug efflux plus target-gene mutations to the drug resistance levels in clinical isolates of M...
2017: Frontiers in Microbiology
https://www.readbyqxmd.com/read/28494730/small-molecule-efflux-pump-inhibitors-in-mycobacterium-tuberculosis-a-rational-drug-design-perspective
#7
Erika Kapp, Sarel F Malan, Samantha L Sampson
Drug resistance in Mycobacterium tuberculosis (M. tuberculosis) complicates management of tuberculosis. Efflux pumps contribute to low level resistance and acquisition of additional high level resistance mutations through sub-therapeutic concentrations of intracellular antimycobacterials. Various efflux pump inhibitors (EPIs) have been described for M. tuberculosis but little is known regarding the mechanism of efflux inhibition. As knowledge relating to the mechanism of action and drug target is central to the rational drug design of safe and sufficiently selective EPIs, this review aims to examine recent developments in the study of EPIs in M...
May 9, 2017: Mini Reviews in Medicinal Chemistry
https://www.readbyqxmd.com/read/28493713/cetuximab-prevents-methotrexate-induced-cytotoxicity-in-vitro-through-epidermal-growth-factor-dependent-regulation-of-renal-drug-transporters
#8
Pedro Caetano-Pinto, Amer Jamalpoor, Janneke Ham, Anastasia Goumenou, Monique Mommersteeg, Dirk Pijnenburg, Rob Ruijtenbeek, Natalia Sánchez-Romero, Bertrand van Zelst, Sandra Heil, Jitske Jansen, Martijn J Wilmer, Carla M L van Herpen, Rosalinde Masereeuw
The combination of methotrexate with epidermal growth factor receptor (EGFR) recombinant antibody, cetuximab, is currently being investigated in treatment of head and neck carcinoma. As methotrexate is cleared by renal excretion, we studied the effect of cetuximab on renal methotrexate handling. We used human conditionally immortalized proximal tubule epithelial cells over-expressing either organic anion transporter 1 or 3 (ciPTEC-OAT1/ciPTEC-OAT3) to examine OAT1 and OAT3, and the efflux pumps breast cancer resistance protein (BCRP), multidrug resistance protein 4 (MRP4) and P-glycoprotein (P-gp) in methotrexate handling upon EGF and/or cetuximab treatment...
May 11, 2017: Molecular Pharmaceutics
https://www.readbyqxmd.com/read/28490701/-adeabc-efflux-pump-and-resistance-of-acinetobacter-baumannii-against-carbapenem
#9
Qingya Dou, Mingxiang Zou, Jun Li, Haichen Wang, Yongmei Hu, Wen'en Liu
To investigate relationship between AdeABC efflux pump and resistance of Acinetobacter baumannii against carbapenem.
 Methods: Carbapenem-resistant strains were acquired from multistep selection resistance test by meropenem in vitro. The quantitation test for sensitivities of strains before and after induction was determined by the E-test, and carbonylcyanide-m-chlorophenylhydrazone (CCCP) inhibition test was used to screen efflux pump. PCR, sequencing analysis, or real-time PCR was used to analyze the changes of regulatory genes adeR and adeS of the AdeABC efflux pump system, or expressions of adeA, adeB, adeR, and adeS in the strains before and after induction, respectively...
April 28, 2017: Zhong Nan da Xue Xue Bao. Yi Xue Ban, Journal of Central South University. Medical Sciences
https://www.readbyqxmd.com/read/28462872/interaction-of-ethidium-and-tetraphenylphosphonium-cations-with-salmonella-enterica-cells
#10
Valeryia Mikalayeva, Sandra Sakalauskaitė, Rimantas Daugelavičius
BACKGROUND AND OBJECTIVE: One of the main causes of bacterial resistance to antimicrobials is multidrug resistance induced by the increased efficiency of the efflux pumps. In this study we analyzed how the conditions of assay affect the efflux of indicator substrates ethidium (Et(+)) and tetraphenylphosphonium (TPP(+)) in Salmonella enterica ser. Typhimurium cells. Impact of the outer membrane permeability barrier, composition and temperature of the medium on accumulation of the indicator compounds also was analyzed...
April 17, 2017: Medicina
https://www.readbyqxmd.com/read/28461316/competitive-fitness-of-fluconazole-resistant-clinical-candida-albicans-strains
#11
Christina Popp, Irene Hampe, Tobias Hertlein, Knut Ohlsen, P David Rogers, Joachim Morschhäuser
The pathogenic yeast Candida albicans can develop resistance to the widely used antifungal agent fluconazole, which inhibits ergosterol biosynthesis. Resistance is often caused by gain-of-function mutations in the transcription factors Mrr1, Tac1, and Upc2, which result in constitutive overexpression of multidrug efflux pumps and ergosterol biosynthesis genes, respectively. However, the deregulated gene expression that is caused by hyperactive forms of these transcription factors also reduces the fitness of the cells in the absence of the drug...
May 1, 2017: Antimicrobial Agents and Chemotherapy
https://www.readbyqxmd.com/read/28451309/a-multi-functional-pegylated-gold-iii-compound-potent-anti-cancer-properties-and-self-assembly-into-nanostructures-for-drug-co-delivery
#12
Clive Yik-Sham Chung, Sin-Ki Fung, Ka-Chung Tong, Pui-Ki Wan, Chun-Nam Lok, Yanyu Huang, Tianfeng Chen, Chi-Ming Che
Gold(iii) porphyrin-PEG conjugates [Au(TPP-COO-PEG5000-OCH3)]Cl (1) and [Au(TPP-CONH-PEG5000-OCH3)]Cl (2) have been synthesized and characterized. Based on the amphiphilic character of the conjugates, they were found to undergo self-assembly into nanostructures with size 120-200 nm and this did not require the presence of other surfactants or components for nano-assembly, unlike most conventional drug nano-formulations. With a readily hydrolyzable ester linkage, chemotherapeutic [Au(TPP-COOH)](+) exhibited triggered release from the conjugate 1 in acidic buffer solution as well as in vitro and in vivo without the formation of toxic side products...
March 1, 2017: Chemical Science
https://www.readbyqxmd.com/read/28438781/transporter-mediated-disposition-clinical-pharmacokinetics-and-cholestatic-potential-of-glyburide-and-its-primary-active-metabolites
#13
Rui Li, Yi-An Bi, Anna Vildhede, Renato J Scialis, Sumathy Mathialagan, Xin Yang, Lisa D Marroquin, Jian Lin, Manthena V S Varma
Glyburide is widely used for the treatment of type 2 diabetes mellitus. We studied the mechanisms involved in the disposition of glyburide and its pharmacologically active hydroxy metabolites, M1 and M2b; and evaluated their clinical pharmacokinetics and the potential role in glyburide-induced cholestasis employing physiologically based pharmacokinetic (PBPK) modeling. Transport studies of parent and metabolites in human hepatocytes and transfected cell systems imply hepatic uptake mediated by organic anion transporting polypeptides...
April 24, 2017: Drug Metabolism and Disposition: the Biological Fate of Chemicals
https://www.readbyqxmd.com/read/28435070/siderophores-in-clinical-isolates-of-klebsiella-pneumoniae-promote-ciprofloxacin-resistance-by-inhibiting-the-oxidative-stress
#14
Wenli Zhang, Ying Zhang, Xinxin Wang, Fengshu Ding, Yingmei Fu, Jizi Zhao, Wuqi Song, Ogutu James Opiyo, Fengmin Zhang, Xiaobei Chen
To explore the relevance of and understand the potential mechanisms behind the production of siderophores by clinical isolates of K. pneumoniae and ciprofloxacin (CIP) resistance, we divided the K. pneumoniae isolates into two groups based on bacterial siderophores productin: high siderophore-yielding group (39 strains) and low siderophore-yielding group (38 strains). The rate of CIP resistance in K. pneumoniae (27/39 = 69.23%) from the high siderophore-yielding group was significantly higher than that (16/38 = 42...
April 20, 2017: Biochemical and Biophysical Research Communications
https://www.readbyqxmd.com/read/28432381/modulation-of-the-multidrug-efflux-pump-emrd-3-from-vibrio-cholerae-by-allium-sativum-extract-and-the-bioactive-agent-allyl-sulfide-plus-synergistic-enhancement-of-antimicrobial-susceptibility-by-a-sativum-extract
#15
Merissa M Bruns, Prathusha Kakarla, Jared T Floyd, Mun Mun Mukherjee, Robert C Ponce, John A Garcia, Indrika Ranaweera, Leslie M Sanford, Alberto J Hernandez, T Mark Willmon, Grace L Tolson, Manuel F Varela
The causative agent of cholera, Vibrio cholerae, is a public health concern. Multidrug-resistant V. cholerae variants may reduce chemotherapeutic efficacies of severe cholera. We previously reported that the multidrug efflux pump EmrD-3 from V. cholerae confers resistance to multiple structurally distinct antimicrobials. Medicinal plant compounds are potential candidates for EmrD-3 efflux pump modulation. The antibacterial activities of garlic Allium sativum, although poorly understood, predicts that a main bioactive component, allyl sulfide, modulates EmrD-3 efflux...
April 21, 2017: Archives of Microbiology
https://www.readbyqxmd.com/read/28427190/pygopus2-inhibits-the-efficacy-of-paclitaxel-induced-apoptosis-and-induces-multidrug-resistance-in-human-glioma-cells
#16
Cefan Zhou, Hongxia Cheng, Wenying Qin, Yi Zhang, Hui Xiong, Jing Yang, Huang Huang, Yefu Wang, Xing-Zhen Chen, Jingfeng Tang
Anti-microtubule drugs, such as paclitaxel (PTX), are extensively used for the treatment of numerous cancers. However, growing evidence has shown that PTX resistance, either intrinsic or acquired, frequently occurs in patients and results in the failure of treatment, contributing to the high cancer mortality rate. Therefore, it is necessary to identify the genes or pathways involved in anti-microtubule drug resistance for future successful treatment of cancers. Pygopus2 (Pygo2), which contains a Zn-coordinated plant homeodomain (PHD) finger domain, is critical for β-catenin-dependent transcriptional switches in normal and malignant tissues and is over-expressed in various cancers, including human brain glioma...
April 25, 2017: Oncotarget
https://www.readbyqxmd.com/read/28411377/mir-495-sensitizes-mdr-cancer-cells-to-the-combination-of-doxorubicin-and-taxol-by-inhibiting-mdr1-expression
#17
Zhenyou Zou, Ruyi Zou, Dan Zong, Yonghong Shi, Jinyao Chen, Jie Huang, Jiahui Zhu, Liguan Chen, Xiaoyan Bao, Yuan Liu, Weihao Liu, Wenhui Huang, Jingsang Hu, Zhi Chen, Xiaojie Lao, Chaoqun Chen, Xiaoli Huang, Yao Lu, Xueyin Ni, Daoquan Fang, Dengqiang Wu, Shuangshuang Lu, Mingzhu Jiang, Chenyang Qiu, Yuya Wu, Qisha Qiu, Yanyuan Dong, Yangyang Su, Chenmin Zhao, Zhihe Zhong, Jing Cai, Yong Liang
MDR1 is highly expressed in MDR A2780DX5 ovarian cancer cells, MDR SGC7901R gastric cancer cells and recurrent tumours. It pumps cytoplasmic agents out of cells, leading to decreased drug accumulation in cells and making cancer cells susceptible to multidrug resistance. Here, we identified that miR-495 was predicted to target ABCB1, which encodes protein MDR1. To reduce the drug efflux and reverse MDR in cancer cells, we overexpressed a miR-495 mimic in SGC7901R and A2780DX cells and in transplanted MDR ovarian tumours in vivo...
April 14, 2017: Journal of Cellular and Molecular Medicine
https://www.readbyqxmd.com/read/28408143/tetrandrine-potentiates-the-glucocorticoid-pharmacodynamics-via-inhibiting-p-glycoprotein-and-mitogen-activated-protein-kinase-in-mitogen-activated-human-peripheral-blood-mononuclear-cells
#18
Wencheng Xu, Kehan Meng, Yuanchao Tu, Sachiko Tanaka, Kenji Onda, Kentaro Sugiyama, Toshihiko Hirano, Haruki Yamada
Glucocorticoids play significant roles in treatments of inflammatory and autoimmune diseases. Some patients show a poor or absent response even to high doses of glucocorticoids. The purpose of this study was to explore whether tetrandrine combined with glucocorticoids could be a new treatment strategy to resolve glucocorticoids resistance. Information on glucocorticoids sensitivity was usually obtained through mitogen-activated human peripheral blood mononuclear cells in cell culture procedures. Thus, human peripheral blood mononuclear cells was chosen as a model to study the immunosuppressive effect of methylprednisolone combined with tetrandrine, including the possible action mechanisms...
April 11, 2017: European Journal of Pharmacology
https://www.readbyqxmd.com/read/28394295/antimicrobial-resistance-and-the-alternative-resources-with-special-emphasis-on-plant-based-antimicrobials-a-review
#19
REVIEW
Harish Chandra, Parul Bishnoi, Archana Yadav, Babita Patni, Abhay Prakash Mishra, Anant Ram Nautiyal
Indiscriminate and irrational use of antibiotics has created an unprecedented challenge for human civilization due to microbe's development of antimicrobial resistance. It is difficult to treat bacterial infection due to bacteria's ability to develop resistance against antimicrobial agents. Antimicrobial agents are categorized according to their mechanism of action, i.e., interference with cell wall synthesis, DNA and RNA synthesis, lysis of the bacterial membrane, inhibition of protein synthesis, inhibition of metabolic pathways, etc...
April 10, 2017: Plants (Basel, Switzerland)
https://www.readbyqxmd.com/read/28393677/in-silico-high-throughput-virtual-screening-and-molecular-dynamics-simulation-study-to-identify-inhibitor-for-adeabc-efflux-pump-of-acinetobacter-baumannii
#20
Privita Verma, Monalisa Tiwari, Vishvanath Tiwari
Emergence of multi-drug resistant strains of Acinetobacter baumannii has caused significant health problems and is responsible for high morbidity and mortality. Overexpression of AdeABC efflux system is one of the major mechanisms. In this study, we have focused on overcoming the drug resistance by identifying inhibitors that can effectively bind and inhibit integral membrane protein, AdeB of this efflux pump. We performed homology modeling to generate structure of AdeB using MODELLER v9.16 followed by model refinement using 3D-Refine tool and validated using PSVS, ProsaWeb, ERRAT etc...
April 10, 2017: Journal of Biomolecular Structure & Dynamics
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