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bacterial efflux

Ziad Abi Khattar, Anne Lanois, Linda Hadchity, Sophie Gaudriault, Alain Givaudan
Photorhabdus luminescens is an enterobacterium establishing a mutualistic symbiosis with nematodes, that also kills insects after septicaemia and connective tissue colonization. The role of the bacterial mdtABC genes encoding a putative multidrug efflux system from the resistance/nodulation/cell division family was investigated. We showed that a mdtA mutant and the wild type had similar levels of resistance to antibiotics, antimicrobial peptides, metals, detergents and bile salts. The mdtA mutant was also as pathogenic as the wild-type following intrahaemocoel injection in Locusta migratoria, but had a slightly attenuated phenotype in Spodoptera littoralis...
2019: PloS One
Chaobin Jin, Rawaf Alenazy, Yinhu Wang, Rumana Mowla, Yinhui Qin, Jin Quan Eugene Tan, Natansh Deepak Modi, Xinjie Gu, Steven W Polyak, Henrietta Venter, Shutao Ma
A series of novel 5-methoxy-2,3-naphthalimide derivatives were designed, synthesized and evaluated for their biological activities. In particular, the ability of the compounds to synergize with antimicrobials, to inhibit Nile Red efflux, and to target AcrB was assayed. The results showed that the most of the tested compounds more sensitized the Escherichia coli BW25113 to the antibiotics than the parent compounds 7c and 15, which were able to inhibit Nile Red efflux. Significantly, compound A5 possessed the most potent antibacterial synergizing activity in combination with levofloxacin by 4 times and 16 times at the concentration of 8 and 16 µg/mL, respectively, whilst A5 could effectively abolish Nile Red efflux at 100 μM...
February 4, 2019: Bioorganic & Medicinal Chemistry Letters
Megan M Nelson, Christopher L Waldron, John R Bracht
BACKGROUND: Emerging antimicrobial resistance is a significant threat to human health. However, methods for rapidly diagnosing antimicrobial resistance generally require multi-day culture-based assays. Macrolide efflux gene A, mef(A), provides resistance against erythromycin and azithromycin and is known to be laterally transferred among a wide range of bacterial species. METHODS: We use Recombinase Polymerase Assay (RPA) to detect the antimicrobial resistance gene mef(A) from raw lysates without nucleic acid purification...
February 12, 2019: BMC Infectious Diseases
Tatiana Tozar, Viorel Nastasa, Alexandru Stoicu, Mariana Carmen Chifiriuc, Marcela Popa, Crina Kamerzan, Mihail Lucian Pascu
Aqueous chlorpromazine solutions exposed to 266 nm generated as fourth harmonic of Nd:YAG pulsed laser along time intervals from 1 min to 240 min were investigated for their antimicrobial activity against planktonic and adherent Gram-positive bacterial strains. Qualitative and quantitative assays based on microbiological methods and flow cytometry assays were performed to establish the minimum inhibitory and minimum biofilm eradication concentrations and to reveal some of the possible mechanisms of antimicrobial activity...
February 8, 2019: Microbial Pathogenesis
Dusik Kim, Junwei Huang, Arnaud Billet, Asmahan Abu-Arish, Julie Goepp, Elizabeth Matthes, Marc A Tewfik, Saul Frenkiel, John W Hanrahan
Bicarbonate facilitates mucin unpacking and bacterial killing however its transport mechanisms in the airways are not well understood. cAMP stimulates anion efflux through the CFTR (ABCC7) anion channel and this is defective in CF. The anion exchanger pendrin (SLC26A4) also mediates HCO3- efflux and is upregulated by proinflammatory cytokines. Here we examined pendrin and CFTR expression and their contributions to HCO3- secretion by human nasal and bronchial epithelia. In native tissue, both proteins were most abundant at the apical pole of ciliated surface cells with little expression in submucosal glands...
February 11, 2019: American Journal of Respiratory Cell and Molecular Biology
Heerasing Takooree, Muhammad Z Aumeeruddy, Kannan R R Rengasamy, Katharigatta N Venugopala, Rajesh Jeewon, Gokhan Zengin, Mohamad F Mahoomodally
Considered as the "King of spices", black pepper (Piper nigrum L.) is a widely used spice which adds flavor of its own to dishes, and also enhances the taste of other ingredients. Piper nigrum has also been extensively explored for its biological properties and its bioactive phyto-compounds. There is, however, no updated compilation of these available data to provide a complete profile of the medicinal aspects of P. nigrum. This study endeavors to systematically review scientific data on the traditional uses, phytochemical composition, and pharmacological properties of P...
February 11, 2019: Critical Reviews in Food Science and Nutrition
Gulrukh Iqbal, Sulaiman Faisal, Sara Khan, Dilawar Farhan Shams, Akhtar Nadhman
Multidrug resistance (MDR) in bacteria is a major concern these days. One of the reasons is the mutation in efflux pump that prevents the retention of antibiotics and drugs in the bacterial cell. The current work is a step to overcome MDR in bacteria via inhibition of efflux pump and further photoinhibition by thiolated chitosan coated cobalt doped zinc oxide nanoparticles (Co-ZnO) in visible light. Co-ZnO were synthesized in a size range of 40-60 nm. Antibacterial activity of the Co-ZnO against methicillin resistant Staphylococcus aureus (MRSA) was found 100% at a concentration of 10 μg/ml upon activation in sunlight for 15 min...
January 31, 2019: Journal of Photochemistry and Photobiology. B, Biology
Jhih-Hang Jiang, Karl A Hassan, Stephanie L Begg, Thusitha W T Rupasinghe, Varsha Naidu, Victoria G Pederick, Marjan Khorvash, Jonathan J Whittall, James C Paton, Ian T Paulsen, Christopher A McDevitt, Anton Y Peleg, Bart A Eijkelkamp
Free fatty acids hold important immune-modulatory roles during infection. However, the host's long-chain polyunsaturated fatty acids, not commonly found in the membranes of bacterial pathogens, also have significant broad-spectrum antibacterial potential. Of these, the omega-6 fatty acid arachidonic acid (AA) and the omega-3 fatty acid decosahexaenoic acid (DHA) are highly abundant; hence, we investigated their effects on the multidrug-resistant human pathogen Acinetobacter baumannii Our analyses reveal that AA and DHA incorporate into the A...
February 5, 2019: MBio
Matthew E Wand, Shirin Jamshidi, Lucy J Bock, Khondaker Miraz Rahman, J Mark Sutton
The multidrug resistant (MDR) opportunistic pathogen Klebsiella pneumoniae has previously been shown to adapt to chlorhexidine by increasing expression of the MFS efflux pump smvA. Here we show that loss of the regulator SmvR, through adaptation to chlorhexidine, results in increased resistance to a number of cationic biocides in K. pneumoniae and other members of the Enterobacteriaceae. Clinical Enterobacteriaceae isolates which lack smvA and smvR also have an increased susceptibility to chlorhexidine. When smvA from Salmonella and K...
February 4, 2019: Scientific Reports
Lorena Novoa-Aponte, David Ramírez, José M Argüello
Copper homeostasis in pathogenic bacteria is critical for cuproprotein assembly and virulence. However, in vivo biochemical analyses of these processes are challenging, which has prevented defining and quantifying the homeostatic interplay between Cu+ -sensing transcriptional regulators, chaperones, and sequestering molecules. The cytoplasm of Pseudomonas aeruginosa contains a Cu+ -sensing transcriptional regulator, CueR, and two homologous metal chaperones, CopZ1 and CopZ2, forming a unique system for studying Cu+ homeostasis...
February 4, 2019: Journal of Biological Chemistry
Günter Kampf
Some biocidal agents used for disinfection have been described to enhance antibiotic resistance in Gram-negative species. The aim of this review was therefore to evaluate the effect of 13 biocidal agents at sublethal concentrations on antibiotic resistance in Gram-positive species. A MEDLINE search was performed for each biocidal agent on antibiotic tolerance, antibiotic resistance, horizontal gene transfer, and efflux pump. Most data were reported with food-associated bacterial species. In cells adapted to benzalkonium chloride, a new resistance was most frequently found to ampicillin (seven species), cefotaxime and sulfamethoxazole (six species each), and ceftazidime (five species), some of them with relevance for healthcare-associated infections such as Enterococcus faecium and Enterococcus faecalis ...
February 1, 2019: Antibiotics
Wen-Jung Lu, Hsuan-Ju Lin, Pang-Hung Hsu, Margaret Lai, Jen-Yu Chiu, Hong-Ting Victor Lin
Multidrug-resistant pathogens are a significant clinical problem. Efflux pump inhibitors (EPIs) can restore the activities of existing antibiotics by interfering with drug efflux pumps located in bacterial cell membranes. Seaweeds are important sources of biologically active metabolites of natural origin; however, their potential as EPIs remains uninvestigated. Here, functional extracts from the brown seaweeds Laminaria japonica and Sargassum horneri and the red seaweeds Gracilaria sp. and Porphyra dentata were evaluated as potential EPIs against drug-resistant Escherichia coli ...
2019: Evidence-based Complementary and Alternative Medicine: ECAM
Lei Li, Jinyun Li, Jing Peng, Wenliang Wu, Yanbin Guo
AIMS: Rahnella aquatilis is a gram-negative bacterial species with potential for agricultural and industrial applications, as well as a human pathogen. This study aims to identify an optimal reference gene to explore antibiotic-resistance and stress tolerance in R. aquatilis using reverse-transcription quantitative polymerase chain reaction (RT-qPCR). METHODS AND RESULTS: Expression levels of 14 housekeeping genes in R. aquatilis were estimated by RT-qPCR under six different conditions: exponential phase, stationary phase, acid, salinity, antibiotic, and oxidative stresses...
January 31, 2019: Journal of Applied Microbiology
Huichun Tong, Xinhui Wang, Yuzhu Dong, Qingqing Hu, Ziyi Zhao, Yun Zhu, Linxuan Dong, Fan Bai, Xiuzhu Dong
Aquaporins (AQPs) are transmembrane proteins widely distributed in various organisms and facilitate bidirectional diffusion of water and uncharged solutes. The catalase-negative bacterium Streptococcus oligofermentans produces the highest H2O2 levels reported to date, which has to be exported to avoid oxidative stress. Here, we report that a S. oligofermentans aquaporin functions as a peroxiporin facilitating bidirectional transmembrane H2O2 transport. Knockout of this aquaporin homolog, So-AqpA, reduced H2O2 export by approximately 50% and increased endogenous H2O2 retention, as indicated by the cellular H2O2 reporter HyPer...
January 31, 2019: Journal of Biological Chemistry
Lilit Gabrielyan, Lilit Hakobyan, Ashkhen Hovhannisyan, Armen Trchounian
AIMS: Antibiotic resistance of different bacteria requires the development of alternative approaches for overcoming this phenomenon. The antibacterial effects of iron oxide (Fe3 O4 ) nanoparticles (NPs) (from 50 μg mL-1 to 250 μg mL-1 ) on Escherichia coli antibiotic-resistant strains have been aimed. METHODS AND RESULTS: The study was performed with ampicillin-resistant E. coli DH5α-pUC18 and kanamycin-resistant E. coli pARG-25 stains. Specific growth rate of bacteria (μ), lag phase duration and colony forming units (CFU) were determined to evaluate growth properties...
January 31, 2019: Journal of Applied Microbiology
Saleh F Alquethamy, Marjan Khorvash, Victoria G Pederick, Jonathan J Whittall, James C Paton, Ian T Paulsen, Karl A Hassan, Christopher A McDevitt, Bart A Eijkelkamp
Acinetobacter baumannii has emerged as one of the leading causative agents of nosocomial infections. Due to its high level of intrinsic and adapted antibiotic resistance, treatment failure rates are high, which allows this opportunistic pathogen to thrive during infection in immune-compromised patients. A. baumannii can cause infections within a broad range of host niches, with pneumonia and bacteraemia being associated with the greatest levels of morbidity and mortality. Although its resistance to antibiotics is widely studied, our understanding of the mechanisms required for dealing with environmental stresses related to virulence and hospital persistence, such as copper toxicity, is limited...
January 29, 2019: International Journal of Molecular Sciences
Tomislav Cernava, Armin Erlacher, Jung Soh, Christoph W Sensen, Martin Grube, Gabriele Berg
BACKGROUND: Arugula is a traditional medicinal plant and popular leafy green today. It is mainly consumed raw in the Western cuisine and known to contain various bioactive secondary metabolites. However, arugula has been also associated with high-profile outbreaks causing severe food-borne human diseases. A multiphasic approach integrating data from metagenomics, amplicon sequencing, and arugula-derived bacterial cultures was employed to understand the specificity of the indigenous microbiome and resistome of the edible plant parts...
January 29, 2019: Microbiome
D Keller, S Verbruggen, H Cash, S Farmer, K Venema
The aim of this study was to assess the germination, survival and metabolic activity of the probiotic Bacillus coagulans GBI-30, 6086 [GanedenBC30 ] (BC30) in a dynamic, computer controlled in vitro model of the gastrointestinal (GI) tract, simulating human adults. Experiments were performed in the presence of a meal to maximise germination, due to the presence of germination-triggers. Both an upper GI tract (stomach and small intestine; TIM-1) and a colon model (TIM-2) were used, where material exiting TIM-1 was added to TIM-2...
January 29, 2019: Beneficial Microbes
Aneta Kaczor, Karolina Witek, Sabina Podlewska, Joanna Czekajewska, Annamaria Lubelska, Ewa Żesławska, Wojciech Nitek, Gniewomir Latacz, Sandrine Alibert, Jean-Marie Pagès, Elżbieta Karczewska, Katarzyna Kieć-Kononowicz, Jadwiga Handzlik
Searching for new chemosensitizers of bacterial multidrug resistance (MDR), chemical modifications of (Z)-5-(4-chlorobenzylidene)-2-(4-methylpiperazin-1-yl)-3H-imidazol-4(5H)-one ( 6 ) were performed. New compounds ( 7 ⁻ 17 ), with fused aromatic rings at position 5, were designed and synthesized. Crystallographic X-ray analysis proved that the final compounds ( 7 ⁻ 17 ) were substituted with tertiary amine-propyl moiety at position 3 and primary amine group at 2 due to intramolecular Dimroth rearrangement...
January 26, 2019: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
Ulrich Schwaneberg, Lingling Zhang, Haiyang Cui, Zhi Zou, Tayebeh Mirzaeigarakani, Catalina Novoa-Henriquez, Bahareh Jooyeh
Escherichia coli's Copper efflux oxidase (CueO), a bacterial laccase, has rarely been employed in the cathodic compartment of enzymatic biofuel cells (EBFCs) due to its low redox potential (0.36 V vs Ag/AgCl, pH 5.5) towards O2 reduction. Herein, directed evolution of CueO towards more positive onset potential was performed by sampling random and site-saturation mutagenesis libraries in a robust electrochemical screening system. Two positions D439 and L502 were found to be involved in improving the onset potential...
January 28, 2019: Angewandte Chemie
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