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bacterial efflux

Thanyaluck Siriyong, Supayang Piyawan Voravuthikunchai, Peter John Coote
BACKGROUND: This study aimed to evaluate the efficacy of combinations of steroidal alkaloids and conessine from the Thai medicinal plant Holarrhena antidysenterica with antibiotics against Pseudomonas aeruginosa strains possessing different efflux-pump-mediated multidrug-resistant (MDR) phenotypes in a Galleria mellonella infection model. METHODS: P. aeruginosa strains with defined mutations that result in the overexpression of the MexAB-OprM, MexCD-OprJ and MexEF-OprN efflux pumps, and a strain with all three of these pumps deleted, were used...
October 19, 2018: BMC Complementary and Alternative Medicine
Lex E X Leong, Diana Lagana, Glen P Carter, Qinning Wang, Kija Smith, Tim P Stinear, David Shaw, Vitali Sintchenko, Steven L Wesselingh, Ivan Bastian, Geraint B Rogers
Burkholderia lata was isolated from 8 intensive care patients at 2 tertiary hospitals in Australia. Whole-genome sequencing demonstrated that clinical and environmental isolates originated from a batch of contaminated commercial chlorhexidine mouthwash. Genomic analysis identified efflux pump-encoding genes as potential facilitators of bacterial persistence within this biocide.
November 2018: Emerging Infectious Diseases
María Antonela Colonnella, Leonardo Lizarraga, Leticia Rossi, Rocío Díaz Peña, Diego Egoburo, Nancy I López, Laura J Raiger Iustman
Environments co-contaminated with heavy metals and hydrocarbons have become an important problem worldwide, especially due to the effect of metals on hydrocarbon degrading microorganisms. Pseudomonas extremaustralis, a bacterium isolated from a pristine pond in Antarctica, showed high capabilities to cope with environmental stress and a very versatile metabolism that includes alkane degradation under microaerobic conditions. In this work, we analyzed P. extremaustralis' capability to resist high copper concentrations and the effect of copper presence in diesel biodegradation...
October 17, 2018: Extremophiles: Life Under Extreme Conditions
Qiwei Chen, Xiaowei Gong, Fuying Zheng, Guo Ji, Shengdou Li, Laszlo Stipkovits, Susan Szathmary, Yongsheng Liu
The number of multidrug-resistant strains of Riemerella anatipestifer continues to increase, and new strategies for the treatment of associated infections are necessary. Recently, numerous studies have shown that efflux pumps (EPs) play key roles in universal bacterial mechanisms that contribute to antibiotic resistance. In addition, studies have shown that the effects of antibiotics that are subjected to efflux can be reinforced by their combined use with efflux pump inhibitors (EPIs). Unfortunately, the role of the efflux system in R...
2018: Frontiers in Microbiology
Marta Zapotoczna, Gustavo P Riboldi, Ahmed M Moustafa, Elizabeth Dickson, Apurva Narechania, Julie A Morrissey, Paul J Planet, Matthew T G Holden, Kevin J Waldron, Joan A Geoghegan
Pathogens are exposed to toxic levels of copper during infection, and copper tolerance may be a general virulence mechanism used by bacteria to resist host defenses. In support of this, inactivation of copper exporter genes has been found to reduce the virulence of bacterial pathogens in vivo Here we investigate the role of copper hypertolerance in methicillin-resistant Staphylococcus aureus (MRSA). We show that a copper hypertolerance operon ( copB-mco ), carried on a mobile genetic element (MGE), is prevalent in a collection of invasive S...
October 16, 2018: MBio
Anne-Marie Salisbury, Kevin Woo, Sandip Sarkar, Greg Schultz, Matthew Malone, Dieter O Mayer, Steven L Percival
A biofilm is a community of microorganisms that adhere to each other and to surfaces and secrete extracellular polymeric substances (EPS) encasing themselves in a matrix. Biofilms are a major healthcare concern, as they can form on medical devices leading to infection. Additionally, there is growing evidence to show their ability to form in chronic wounds, which leads to delayed wound healing and inflammation. Due to a number of reasons, such as formation of the EPS resulting in sub-inhibitory concentrations of antimicrobials reaching the bacterial cells, slow growth rate of bacterial cells rendering some antibiotics ineffective, and the presence of persister cells, biofilms show increased tolerance to many antimicrobials and antibiotics...
October 16, 2018: Surgical Technology International
Estelle Dumont, Julia Vergalli, Laurence Conraux, Carine Taillier, Aurélie Vassort, Jelena Pajovic, Matthieu Réfrégiers, Michael Mourez, Jean-Marie Pagès
Background: In Gram-negative bacteria, passing through the double membrane barrier to reach the inhibitory concentration inside the bacterium is a pivotal step for antibiotic activity. Spectrofluorimetry has been developed to follow fluoroquinolone accumulation inside bacteria using intrinsic bacterial fluorescence as an internal standard. However, adaptation for non-fluorescent antibiotics is needed; quantitative methods based on MS offer the possibility of expanding the detection range obtained by spectrofluorimetry...
October 15, 2018: Journal of Antimicrobial Chemotherapy
Abdelkarim Mahdhi, Nadia Leban, Ibtissem Chakroun, Sihem Bayar, Kacem Mahdouani, Hatem Majdoub, Bochra Kouidhi
The overuse of antibiotics and biofilm formation ability has led to the emergence of bacterial resistant strains. The combined use of several antibiotics has been found as an efficient strategy to overcome this resistance. In this study, two exopolysaccharides (EPS) obtained from Lactobacillus plantarum (EPS-Lp) and Bacillus spp. (EPS-B), isolated from a traditional Tunisian food "ricotta cheese" and hypersaline environment respectively, were used to counteract the biofilm formation and efflux pumps activities in Escherichia coli ATCC35218...
October 10, 2018: Microbial Pathogenesis
Kaixiang Shi, Chan Li, Christopher Rensing, Xingli Dai, Xia Fan, Gejiao Wang
Arsenic-resistant bacteria have evolved various efflux systems for arsenic resistance. Five arsenic efflux proteins, ArsB, Acr3, ArsP, ArsJ and MSF1, have been reported. In this study, comprehensive analyses were performed to study the function of a putative major facilitator superfamily gene arsK and the regulation of arsK transcriptional expression in Agrobacterium tumefaciens GW4. We found that (1) arsK is located on an arsenic gene island in strain GW4, ArsK orthologs are widely distributed in arsenic-resistant bacteria and are phylogenetically divergent from the five reported arsenic efflux proteins, indicating that it may be a novel arsenic efflux transporter; (2) Reporter gene assays showed that the expression of arsK was induced by arsenite [As(III)], antimonite [Sb(III)], trivalent roxarsone [Rox(III)], methylarsenite [MAs(III)] and arsenate [As(V)]; (3) Heterologous expression of ArsK in an arsenic-hypersensitive E...
October 12, 2018: Applied and Environmental Microbiology
Olawale O Adelowo, John Vollmers, Ines Mäusezahl, Anne-Kristin Kaster, Jochen A Müller
There are increasing concerns about possible dissemination of clinically relevant antibiotic resistance genes, including genes encoding for carbapenemases in the environment. However, little is known about environmental distribution of antibiotic resistance in Africa. In this study, four polluted urban wetlands in Nigeria were investigated as potential reservoirs of carbapenem-resistant bacteria (CRB). CRB were isolated from the wetlands, characterized by Blue-Carba test, MIC determinations and whole genome sequencing (WGS)...
October 11, 2018: Scientific Reports
Xi Wen, Ariel M Langevin, Mary J Dunlop
Cell-cell interactions play an important role in bacterial antibiotic resistance. Here, we asked whether neighbor proximity is sufficient to generate single-cell variation in antibiotic resistance due to local differences in antibiotic concentrations. To test this, we focused on multidrug efflux pumps because recent studies have revealed that expression of pumps is heterogeneous across populations. Efflux pumps can export antibiotics, leading to elevated resistance relative to cells with low or no pump expression...
October 11, 2018: Scientific Reports
Muhammad Asif, Ayesha Aziz, Ghazala Ashraf, Zhengyun Wang, Junlei Wang, Muhammad Azeem, Xuedong Chen, Fei Xiao, Hongfang Liu
The development of structurally modified metal oxide heteroarchitectures with higher energy facets exposed has been of extensive research interests because of their unique construction and synergy effect of multifunctioning characteristics. In this study, we reported for the first time the development of a distinct type of gold nanoislands (AuNIs) on metal oxides (i.e., Cu2 O-CuO) octadecahedral (ODH) heterostructures through the galvanic exchange reaction, where Cu2 O not only acts as a stabilizer but also functions as a reductant...
October 18, 2018: ACS Applied Materials & Interfaces
Atsushi Matsumoto, Yukifumi Uesono
The cutoff phenomenon that long-chain alcohols are unable to induce anesthesia is observed for various antimicrobial activities, although its mechanism has remained unknown for over eight decades. The minimum inhibitory concentrations at 25°C for budding yeast growth exponentially decreased with increasing chain length of the n-alcohols (C1 - C12), whereas alcohols (≥C13) lost the inhibitory effect. Thus, the growth inhibition by n-alcohols obeys the Meyer - Overton correlation up to C12 and exhibits a cutoff phenomenon...
October 5, 2018: Molecular Pharmacology
Marlon H Cardoso, Keyla C de Almeida, Elizabete S Cândido, Gabriel da R Fernandes, Simoni C Dias, Sérgio A de Alencar, Octávio L Franco
Antimicrobial peptides (AMPs) have attracted considerable attention because of their multiple and complex mechanisms of action toward resistant bacteria. However, reports have increasingly highlighted how bacteria can escape AMP administration. Here, the molecular mechanisms involved in Escherichia coli resistance to magainin I were investigated through comparative transcriptomics. Sub-inhibitory concentrations of magainin I were used to generate four experimental groups, including magainin I-susceptible E...
October 2, 2018: Microbiology
Kumar Nagarathinam, Yoshiko Nakada-Nakura, Christoph Parthier, Tohru Terada, Narinobu Juge, Frank Jaenecke, Kehong Liu, Yunhon Hotta, Takaaki Miyaji, Hiroshi Omote, So Iwata, Norimichi Nomura, Milton T Stubbs, Mikio Tanabe
Multidrug resistance (MDR) poses a major challenge to medicine. A principle cause of MDR is through active efflux by MDR transporters situated in the bacterial membrane. Here we present the crystal structure of the major facilitator superfamily (MFS) drug/H+ antiporter MdfA from Escherichia coli in an outward open conformation. Comparison with the inward facing (drug binding) state shows that, in addition to the expected change in relative orientations of the N- and C-terminal lobes of the antiporter, the conformation of TM5 is kinked and twisted...
October 1, 2018: Nature Communications
Carlos Carmelo Pérez-Marín, Guillermo Vizuete, Carmen Borge, Juan Jose Galisteo
While testing for uterine bacterial infection is usually performed prior to artificial insemination (AI), samples taken during or after embryo flushing are generally not assessed either in subfertile and old mares or in fertile mares, even though knowledge of the status of the uterine environment in which the embryo is to develop would help to predict the outcome of embryo transfer programmes. The presence of bacteria and inflammatory cells in the liquid retained in the filter after uterine flushing in donors was determined at the moment of embryo recovery...
September 2018: Acta Veterinaria Hungarica
Stéphanie Bouillot, Emeline Reboud, Philippe Huber
Bacterial pore-forming toxins induce a rapid and massive increase in cytosolic Ca2+ concentration due to the formation of pores in the plasma membrane and/or activation of Ca2+ -channels. As Ca2+ is an essential messenger in cellular signaling, a sustained increase in Ca2+ concentration has dramatic consequences on cellular behavior, eventually leading to cell death. However, host cells have adapted mechanisms to protect against Ca2+ intoxication, such as Ca2+ efflux and membrane repair. The final outcome depends upon the nature and concentration of the toxin and on the cell type...
September 25, 2018: Toxins
Kelvin Agboh, Calvin H F Lau, Yvonne S K Khoo, Himansha Singh, Sagar Raturi, Asha V Nair, Julie Howard, Marco Chiapello, Renata Feret, Michael J Deery, Satoshi Murakami, Hendrik W van Veen
LmrA is a bacterial ATP-binding cassette (ABC) multidrug exporter that uses metabolic energy to transport ions, cytotoxic drugs, and lipids. Voltage clamping in a Port-a-Patch was used to monitor electrical currents associated with the transport of monovalent cationic HEPES+ by single-LmrA transporters and ensembles of transporters. In these experiments, one proton and one chloride ion are effluxed together with each HEPES+ ion out of the inner compartment, whereas two sodium ions are transported into this compartment...
September 2018: Science Advances
Devon Radford, Philip Strange, Dion Lepp, Marta Hernandez, Muhammad Attiq Rehman, Moussa Sory Diarra, S Balamurugan
With the alarming proliferation of antibiotic resistance, it is important to understand the de novo development of bacterial adaptation to antibiotics in formerly susceptible lineages, in the absence of external genetic input from existing resistance pools. A strain of ceftiofur susceptible Salmonella enterica serovar Enteritidis ABB07-SB3071 (MIC = 1.0 μg/ml) was successively exposed to sub-MIC of ceftiofur to allow its adaptation for tolerance to a concentration of 2.0 μg/ml of this antibiotic. Genomic and proteomic comparative analyses of the parental strain and induced tolerant derived lineages were performed to characterize underlying mechanisms of de novo adaptation (tolerance)...
2018: Frontiers in Microbiology
Rebecca Feltham, James E Vince
The pore-forming protein GSDMD promotes cytokine release and induces pyroptotic cell death. In this issue of Immunity, Banerjee et al. (2018) document how GSDMD triggers potassium efflux to inhibit cGAS-STING and prevent damaging interferon production after bacterial infection.
September 18, 2018: Immunity
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