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Antibiotic Efflux

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https://www.readbyqxmd.com/read/29054003/adhesion-force-sensing-and-activation-of-a-membrane-bound-sensor-to-activate-nisin-efflux-pumps-in-staphylococcus-aureus-under-mechanical-and-chemical-stresses
#1
Vera Carniello, Akshay K Harapanahalli, Henk J Busscher, Henny C van der Mei
Nisin-associated-sensitivity-response-regulator (NsaRS) in Staphylococcus aureus is important for its adhesion to surfaces and resistance against antibiotics, like nisin. NsaRS consists of an intra-membrane-located sensor NsaS and a cytoplasmatically-located response-regulator NsaR, which becomes activated upon receiving phosphate groups from the intra-membrane-located sensor. HYPOTHESIS: The intra-membrane location of the NsaS sensor leads us to hypothesize that the two-component NsaRS system not only senses "chemical" (nisin) but also "mechanical" (adhesion) stresses to modulate efflux of antibiotics from the cytoplasm...
October 7, 2017: Journal of Colloid and Interface Science
https://www.readbyqxmd.com/read/29050768/single-nucleotide-polymorphisms-in-efflux-pumps-genes-in-extensively-drug-resistant-mycobacterium-tuberculosis-isolates-from-pakistan
#2
Akbar Kanji, Rumina Hasan, Asho Ali, Ambreen Zaver, Ying Zhang, Kehkashan Imtiaz, Wanliang Shi, Taane G Clark, Ruth McNerney, Jody Phelan, Shoaib Rao, Samreen Shafiq, Zahra Hasan
It is challenging to understand mechanisms of drug resistance in Mycobacterium tuberculosis (MTB) due to the large variability in resistance associated genes. Efflux pump genes contribute to drug resistance and thus add to this complexity. Efflux pump gene protein superfamilies have been characterized by genome analysis of drug resistant strains and through in vitro transcriptional studies. However, there is limited information regarding efflux pump genes in extensively drug resistant (XDR) tuberculosis (TB) isolates...
December 2017: Tuberculosis
https://www.readbyqxmd.com/read/29050760/mmps5-mmpl5-as-an-efflux-pump-in-mycobacterium-species
#3
REVIEW
Julien Briffotaux, Wei Huang, Xinwei Wang, Brigitte Gicquel
Tuberculosis remains an important cause of morbidity and mortality throughout the world, amplified by the expansion of antibiotic resistance. Increasing active efflux of the antibiotic is one of the several strategies used by bacteria to resist to antibiotics. After showing the importance of the RND superfamily of efflux pumps in drug resistance, this review focuses on the protein MmpL5, a transmembrane transporter of Mycobacterium. These exporters should be involved in the variety of roles in bacterial cells, including expelling various drugs...
December 2017: Tuberculosis
https://www.readbyqxmd.com/read/29045498/novel-drug-targets-in-cell-wall-biosynthesis-exploited-by-gene-disruption-in-pseudomonas-aeruginosa
#4
Ayssar A Elamin, Susanne Steinicke, Wulf Oehlmann, Yvonne Braun, Hanaa Wanas, Eduard A Shuralev, Carmen Huck, Marko Maringer, Manfred Rohde, Mahavir Singh
For clinicians, Pseudomonas aeruginosa is a nightmare pathogen that is one of the top three causes of opportunistic human infections. Therapy of P. aeruginosa infections is complicated due to its natural high intrinsic resistance to antibiotics. Active efflux and decreased uptake of drugs due to cell wall/membrane permeability appear to be important issues in the acquired antibiotic tolerance mechanisms. Bacterial cell wall biosynthesis enzymes have been shown to be essential for pathogenicity of Gram-negative bacteria...
2017: PloS One
https://www.readbyqxmd.com/read/29038251/stress-introduction-rate-alters-benefit-of-acrab-tolc-efflux-pumps
#5
Ariel M Langevin, Mary J Dunlop
Stress tolerance studies are typically conducted in an all-or-none fashion. However, in realistic settings-such as in clinical or metabolic engineering applications-cells may encounter stresses at different rates. As such, how cells tolerate stress may depend on its rate of appearance. To address this, we study how the rate of introduction affects bacterial stress tolerance by focusing on a key mechanism for stress response. Efflux pumps, such as AcrAB-TolC from Escherichia coli, are membrane transporters well known for their ability to export a wide variety of substrates, including antibiotics, signaling molecules, and biofuels...
October 16, 2017: Journal of Bacteriology
https://www.readbyqxmd.com/read/29033910/resistance-of-animal-strains-of-pseudomonas-aeruginosa-to-carbapenems
#6
Marisa Haenni, Maxime Bour, Pierre Châtre, Jean-Yves Madec, Patrick Plésiat, Katy Jeannot
Carbapenems are major antibiotics reserved to human medicine. This study aimed to investigate the mechanisms of carbapenem resistance of a selection of Pseudomonas aeruginosa veterinary strains from the French network Resapath. Thirty (5.7%) imipenem and/or meropenem non-susceptible P. aeruginosa of canine (n = 24), feline (n = 5), or bovine (n = 1) origin were identified in a large collection of 527 veterinary strains gathered by the Resapath. These resistant isolates belonged to 25 MultiLocus Sequence Types (MLST), of which 17 (68%) are shared with clinical (human) strains, such as high risk clones ST233 and ST395...
2017: Frontiers in Microbiology
https://www.readbyqxmd.com/read/29033110/investigating-of-four-main-carbapenem-resistance-mechanisms-in-high-level-carbapenem-resistant-pseudomonas-aeruginosa-isolated-from-burn-patients
#7
Soodabeh Rostami, Ahmad Farajzadeh Sheikh, Saeed Shoja, Abbas Farahani, Mohammad Amin Tabatabaiefar, Abbas Jolodar, Raheleh Sheikhi
BACKGROUND: Pseudomonas aeruginosa is an opportunistic pathogen involved in many infections. Carbapenem-resistant P.aeruginosa has emerged as an important cause of infection in different hospitals worldwide. We aimed to determine frequencies of the four main resistance mechanisms [metallo-beta lactamase (MBL) production (blaIMP, blaVIM, blaSPM and blaNDM), overproduction of the MexAB-OprM and MexXY efflux pumps, overproduction of chromosome-encoded AmpC β-lactamase, and reduced OprD expression] in high-level carbapenem-resistant P...
October 9, 2017: Journal of the Chinese Medical Association: JCMA
https://www.readbyqxmd.com/read/29030440/multiple-roles-of-two-efflux-pumps-in-a-polycyclic-aromatic-hydrocarbon-degrading-pseudomonas-putida-strain-b6-2-dsm-28064
#8
Xuemei Yao, Fei Tao, Kunzhi Zhang, Hongzhi Tang, Ping Xu
Microbial bioremediation is a promising approach for the removal of polycyclic aromatic hydrocarbon (PAH) contaminants. Many degraders of PAHs possess efflux pump genes in their genomes; however, their specific roles in the degradation of PAHs have not been clearly elucidated. In this study, two efflux pumps, TtgABC and SrpABC, were systematically investigated to determine their functions in a PAH-degrading Pseudomonas putida strain B6-2 (DSM 28064). The disruption of genes ttgABC or srpABC resulted in a defect in organic solvent tolerance...
October 13, 2017: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/29029194/envelope-proteome-changes-driven-by-rama-overproduction-in-klebsiella-pneumoniae-that-enhance-acquired-%C3%AE-lactam-resistance
#9
Juan-Carlos Jiménez-Castellanos, Wan Ahmad Kamil Wan Nur Ismah, Yuiko Takebayashi, Jacqueline Findlay, Thamarai Schneiders, Kate J Heesom, Matthew B Avison
Objectives: In Klebsiella pneumoniae, overproduction of RamA results in reduced envelope permeability and reduced antimicrobial susceptibility but clinically relevant resistance is rarely observed. Here we have tested whether RamA overproduction can enhance acquired β-lactam resistance mechanisms in K. pneumoniae and have defined the envelope protein abundance changes upon RamA overproduction during growth in low and high osmolarity media. Methods: Envelope permeability was estimated using a fluorescent dye accumulation assay...
October 6, 2017: Journal of Antimicrobial Chemotherapy
https://www.readbyqxmd.com/read/29018620/mechanisms-of-action-and-in-vivo-antibacterial-efficacy-assessment-of-five-novel-hybrid-peptides-derived-from-indolicidin-and-ranalexin-against-streptococcus-pneumoniae
#10
Hassan Mahmood Jindal, Keivan Zandi, Kien Chai Ong, Rukumani Devi Velayuthan, Sara Maisha Rasid, Chandramathi Samudi Raju, Shamala Devi Sekaran
BACKGROUND: Antimicrobial peptides (AMPs) are of great potential as novel antibiotics for the treatment of broad spectrum of pathogenic microorganisms including resistant bacteria. In this study, the mechanisms of action and the therapeutic efficacy of the hybrid peptides were examined. METHODS: TEM, SEM and ATP efflux assay were used to evaluate the effect of hybrid peptides on the integrity of the pneumococcal cell wall/membrane. DNA retardation assay was assessed to measure the impact of hybrid peptides on the migration of genomic DNA through the agarose gel...
2017: PeerJ
https://www.readbyqxmd.com/read/29018420/molecular-characterization-of-reduced-susceptibility-to-biocides-in-clinical-isolates-of-acinetobacter-baumannii
#11
Fei Lin, Ying Xu, Yaowen Chang, Chao Liu, Xu Jia, Baodong Ling
Active efflux is regarded as a common mechanism for antibiotic and biocide resistance. However, the role of many drug efflux pumps in biocide resistance in Acinetobacter baumannii remains unknown. Using biocide-resistant A. baumannii clinical isolates, we investigated the incidence of 11 known/putative antimicrobial resistance efflux pump genes (adeB, adeG, adeJ, adeT1, adeT2, amvA, abeD, abeM, qacE, qacEΔ1, and aceI) and triclosan target gene fabI through PCR and DNA sequencing. Reverse transcriptase quantitative PCR was conducted to assess the correlation between the efflux pump gene expression and the reduced susceptibility to triclosan or chlorhexidine...
2017: Frontiers in Microbiology
https://www.readbyqxmd.com/read/28993173/role-of-mexab-oprm-and-mexxy-oprm-efflux-pumps-and-class-1-integrons-in-resistance-to-antibiotics-in-burn-and-intensive-care-unit-isolates-of-pseudomonas-aeruginosa
#12
Hamid Reza Goli, Mohammad Reza Nahaei, Mohammad Ahangarzadeh Rezaee, Alka Hasani, Hossein Samadi Kafil, Mohammad Aghazadeh, Mojtaba Nikbakht, Younes Khalili
BACKGROUND: The overexpression of efflux pumps and existence of class 1 integrons are the most important mechanisms that contribute to antimicrobial resistance in Pseudomonas aeruginosa especially in burn and Intensive Care Units (ICUs). The present study evaluated the role of MexAB-OprM and MexXY-OprM efflux pumps and class 1 integrons in resistance to antibiotics in burn and ICU isolates of P. aeruginosa. METHODS: Fifteen burn and forty-two ICU isolates were obtained from four hospitals in Northwest Iran...
October 6, 2017: Journal of Infection and Public Health
https://www.readbyqxmd.com/read/28986689/microbial-resistance-mechanisms-to-the-antibiotic-and-phytotoxin-fusaric-acid
#13
Frankie K Crutcher, Lorraine S Puckhaber, Robert D Stipanovic, Alois A Bell, Robert L Nichols, Katheryn S Lawrence, Jinggao Liu
Fusaric acid (FA) produced by Fusarium oxysporum plays an important role in disease development in plants, including cotton. This non-specific toxin also has antibiotic effects on microorganisms. Thus, one expects a potential pool of diverse detoxification mechanisms of FA in nature. Bacteria and fungi from soils infested with Fusarium and from laboratory sources were evaluated for their ability to grow in the presence of FA and to alter the structure of FA into less toxic compounds. None of the bacterial strains were able to chemically modify FA...
October 6, 2017: Journal of Chemical Ecology
https://www.readbyqxmd.com/read/28983007/draft-genome-sequence-of-extended-spectrum-beta-lactamase-producing-serratia-fonticola-bwk15-isolated-from-feces-of-anas-penelope
#14
Takehiko Kenzaka, Katsuji Tani
Migratory birds have been postulated as potential vehicles of antibiotic resistance. Here we isolated the extended-spectrum beta-lactamase (ESBL)-producing Serratia fonticola strain BWK15 from the feces of Anas penelope The strain's draft genome sequence indicated that it harbors class A ESBL, class C beta-lactamase, and many multidrug efflux pumps.
October 5, 2017: Genome Announcements
https://www.readbyqxmd.com/read/28977678/associations-between-resistance-phenotype-and-gene-expression-in-response-to-serial-exposure-to-oxacillin-and-ciprofloxacin-in-staphylococcus-aureus
#15
Md Jalal Uddin, Juhee Ahn
This study was designed to delineate the relationship between resistance phenotypes and gene expression in wild-type (SA(WT) ), oxacillin-induced (SA(OXA) ), ciprofloxacin-induced (SA(CIP) ), and clinically-acquired antibiotic-resistant Staphylococcus aureus (SA(CA) ) exposed to oxacillin (β-lactam) and ciprofloxacin (fluoroquinolone). The phenotypic response and gene expression were varied with the antibiotic exposure. SA(WT) was highly resistant to oxacillin (MIC=8 μg ml(-1) ) after serial exposure to oxacillin, while the oxacillin susceptibility was not changed in SA(WT) when exposed to ciprofloxacin (MIC=0...
October 4, 2017: Letters in Applied Microbiology
https://www.readbyqxmd.com/read/28975374/effects-of-l-arabinose-efflux-on-%C3%AE-red-recombination-mediated-gene-knockout-in-multiple-antimicrobial-resistant-salmonella-enterica-serovar-choleraesuis
#16
Shi-Wei Liao, Jen-Jie Lee, Christopher P Ptak, Ying-Chen Wu, Shih-Ling Hsuan, Chih-Jung Kuo, Ter-Hsin Chen
In this study, six swine-derived multiple-antimicrobial-resistant (MAR) strains of Salmonella Choleraesuis (S. Choleraesuis) were demonstrated to possess higher efflux pump activity than the wild-type (WT). L-Arabinose, a common inducer for gene expression, modulated S. Choleraesuis efflux pump activity in a dose-dependent manner. At low L-arabinose concentrations, increasing L-arabinose led to a corresponding increase in fluorophore efflux, while at higher L-arabinose concentrations, increasing L-arabinose decreased fluorophore efflux activity...
October 3, 2017: Archives of Microbiology
https://www.readbyqxmd.com/read/28972552/tigecycline-resistant-klebsiella-pneumoniae-isolated-from-austrian-river-water
#17
Alexander Hladicz, Clemens Kittinger, Gernot Zarfel
Abstract: Antibiotic-resistant bacteria are spreading worldwide in medical settings but also in the environment. These resistant bacteria illustrate a major health problem in our times, and last-line antibiotics such as tigecycline represent an ultimate therapy option. Reports on tigecycline non-susceptible Enterobacteriaceae are presented with regard to medical settings but are rare with that for the environment. The aim of this study was to characterize two tigecycline non-susceptible Klebsiella pneumoniae isolates from the river Mur, and to question the resistance mechanism...
October 3, 2017: International Journal of Environmental Research and Public Health
https://www.readbyqxmd.com/read/28970736/comment-on-effect-of-biofilm-formation-by-clinical-isolates-of-helicobacter-pylori-on-the-efflux-mediated-resistance-to-commonly-used-antibiotics
#18
COMMENT
Evangelos I Kazakos, Nick Dorrell, Stergios A Polyzos, Georgia Deretzi, Jannis Kountouras
Attaran et al([1]) have recently shown that decreased susceptibility of established Helicobacter pylori (H. pylori) biofilms to specific antibiotics, was associated with the overtly enhanced transcription of two efflux pump genes, hp1165 and hefA, involved in specific resistance to tetracycline and multiple antibiotics, respectively. Apart from antibiotic exposure, secretion of multiple antimicrobial peptides, such as human β-defensins (hβDs), by the gastric epithelium upon Hp challenge, may act as early triggering events that positively impact biofilm formation and thus, antibiotic resistance...
September 7, 2017: World Journal of Gastroenterology: WJG
https://www.readbyqxmd.com/read/28964825/synergistic-effect-of-eugenol-carvacrol-thymol-p-cymene-and-%C3%AE-terpinene-on-inhibition-of-drug-resistance-and-biofilm-formation-of-oral-bacteria
#19
Hanene Miladi, Tarek Zmantar, Bochra Kouidhi, Yasir Mohammed A Al Qurashi, Amina Bakhrouf, Yassine Chaabouni, Kacem Mahdouani, Kamel Chaieb
Dental caries remains the most prevalent oral infectious disease worldwide. In this study, the antibacterial and the antibiofilm activities of five essential oils (EO's): eugenol (EUG), carvacrol (CAR), thymol (TYH), p-cymene (CYM) and γ-terpinene (TER) were tested (alone or in combinaison with tetracycline) against oral bacteria. In addition, their potential roles to enhance the accumulation of ethidium bromide (EtBr) in bacterial cells were tested. Our results indicated that EO's induced a selective antimicrobial activity...
September 28, 2017: Microbial Pathogenesis
https://www.readbyqxmd.com/read/28959742/the-biofilm-inhibitor-carolacton-enters-gram-negative-cells-studies-using-a-tolc-deficient-strain-of-escherichia-coli
#20
Jannik Donner, Michael Reck, Boyke Bunk, Michael Jarek, Constantin Benjamin App, Jan P Meier-Kolthoff, Jörg Overmann, Rolf Müller, Andreas Kirschning, Irene Wagner-Döbler
The myxobacterial secondary metabolite carolacton inhibits growth of Streptococcus pneumoniae and kills biofilm cells of the caries- and endocarditis-associated pathogen Streptococcus mutans at nanomolar concentrations. Here, we studied the response to carolacton of an Escherichia coli strain that lacked the outer membrane protein TolC. Whole-genome sequencing of the laboratory E. coli strain TolC revealed the integration of an insertion element, IS5, at the tolC locus and a close phylogenetic relationship to the ancient E...
September 2017: MSphere
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