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https://www.readbyqxmd.com/read/29725253/anti-biofilm-and-anti-virulence-efficacy-of-celastrol-against-stenotrophomonas-maltophilia
#1
Hye-Rim Kim, Dongsup Lee, Yong-Bin Eom
Stenotrophomonas maltophilia is a multi-drug resistant opportunistic pathogen that causes nosocomial infections in immunocompromised patients. This pathogen is difficult to treat owing to its intrinsic multidrug resistance and ability to form antimicrobial-tolerant biofilms. In the present study, we aimed to assess the potential use of celastrol as a novel anti-biofilm and/or anti-virulence agent against S. maltophilia . Results showed that celastrol at its sub-inhibitory doses decreased biofilm formation and disrupt the established biofilms produced by S...
2018: International Journal of Medical Sciences
https://www.readbyqxmd.com/read/29712730/pulmonary-surfactant-promotes-virulence-gene-expression-and-biofilm-formation-in-klebsiella-pneumoniae
#2
Graham G Willsey, Sebastian Ventrone, Kristin C Schutz, Aaron M Wallace, John W Ribis, Benjamin T Suratt, Matthew J Wargo
The interactions between K lebsiella pneumoniae and the host environment at the site of infection largely unknown. Pulmonary surfactant serves as an initial point of contact for inhaled bacteria entering the lung and is thought to contain molecular cues that aid colonization and pathogenesis. To gain insight into this ecological transition, we characterized the transcriptional response of K. pneumoniae MGH 78578 to purified pulmonary surfactant. This work revealed changes within the K. pneumoniae transcriptome that likely contribute to host colonization, adaptation, and virulence in vivo Notable transcripts expressed under these conditions include genes involved in capsule synthesis, LPS modification, antibiotic resistance, biofilm formation, and metabolism...
April 30, 2018: Infection and Immunity
https://www.readbyqxmd.com/read/29704774/efficacy-of-hle-a-multidrug-efflux-pump-inhibitor-as-a-disinfectant-against-surface-bacteria
#3
Hikmate Abriouel, Leyre Lavilla Lerma, Beatriz Pérez Montoro, Esther Alonso, Charles W Knapp, Natacha Caballero Gómez, Antonio Gálvez, Nabil Benomar
We evaluated the efficacy of a new disinfectant product, HLE, to inhibit multiple species of planktonic and biofilm bacterial cultures. The HLE disinfectant comprised of EDTA, lactic acid and hydrogen peroxide, and our data indicated that the disinfectant had effective antimicrobial and anti-biofilm activity even at low concentrations (0.15% to 0.4% HLE, v/v). Furthermore, the HLE disinfectant destabilized biofilm structures eradicated them due to the synergistic effect of EDTA and both antimicrobials (lactic acid and hydrogen peroxide), as revealed by confocal laser scanning microscopy...
April 25, 2018: Environmental Research
https://www.readbyqxmd.com/read/29680913/monitoring-of-resistance-genes-in-listeria-monocytogenes-isolates-and-their-presence-in-the-extracellular-dna-of-biofilms-a-case-study-from-the-czech-republic
#4
Martina Boháčová, Kamila Zdeňková, Zuzana Tomáštíková, Viviana Fuchsová, Kateřina Demnerová, Renáta Karpíšková, Jarmila Pazlarová
The alarming occurrence of antibiotic resistance genes in food production demands continuous monitoring worldwide. One reservoir of resistance genes is thought to be eDNA. There is currently little available information in Europe about either the extracellular DNA distribution of the bacterium or the spread of resistance genes in L. monocytogenes. Therefore, our aims were to give insight into the Listeria monocytogenes resistance situation in the Czech Republic and assess the presence of resistance genes in their extracellular DNA (eDNA)...
April 21, 2018: Folia Microbiologica
https://www.readbyqxmd.com/read/29629858/pseudomonas-aeruginosa-puma-acts-on-an-endogenous-phenazine-to-promote-self-resistance
#5
Abigail J Sporer, Christopher Beierschmitt, Anastasia Bendebury, Katherine E Zink, Alexa Price-Whelan, Marisa C Buzzeo, Laura M Sanchez, Lars E P Dietrich
The activities of critical metabolic and regulatory proteins can be altered by exposure to natural or synthetic redox-cycling compounds. Many bacteria, therefore, possess mechanisms to transport or transform these small molecules. The opportunistic pathogen Pseudomonas aeruginosa PA14 synthesizes phenazines, redox-active antibiotics that are toxic to other organisms but have beneficial effects for their producer. Phenazines activate the redox-sensing transcription factor SoxR and thereby induce the transcription of a small regulon, including the operon mexGHI-opmD, which encodes an efflux pump that transports phenazines, and PA14_35160 (pumA), which encodes a putative monooxygenase...
April 9, 2018: Microbiology
https://www.readbyqxmd.com/read/29588855/phage-treatment-of-an-aortic-graft-infected-with-pseudomonas-aeruginosa
#6
Benjamin K Chan, Paul E Turner, Samuel Kim, Hamid R Mojibian, John A Elefteriades, Deepak Narayan
Management of prosthetic vascular graft infections caused by Pseudomonas aeruginosa can be a significant challenge to clinicians. These infections often do not resolve with antibiotic therapy alone due to antibiotic resistance/tolerance by bacteria, poor ability of antibiotics to permeate/reduce biofilms and/or other factors. Bacteriophage OMKO1 binding to efflux pump proteins in P. aeruginosa was consistent with an evolutionary trade-off: wildtype bacteria were killed by phage whereas evolution of phage-resistance led to increased antibiotic sensitivity...
2018: Evolution, Medicine, and Public Health
https://www.readbyqxmd.com/read/29554105/sub-minimum-inhibitory-concentrations-of-colistin-and-polymyxin-b-promote-acinetobacter-baumannii-biofilm-formation
#7
Yoshinori Sato, Yuka Unno, Tsuneyuki Ubagai, Yasuo Ono
We investigated the numbers of planktonic and biofilm cells and the expression levels of genes encoding efflux pumps and biofilm-related proteins in 10 clinical isolates of multi-drug resistant Acinetobacter baumannii (MDRA) as well as in its standard strain ATCC 19606 in the presence of colistin (CST), polymyxin B (PMB), minomycin (MIN), and tigecycline (TGC) at their respective sub-MICs. The number of planktonic and biofilm cells of ATCC 19606 decreased in the presence of all aforementioned antibiotics in a dose-dependent manner...
2018: PloS One
https://www.readbyqxmd.com/read/29506149/role-of-bacterial-efflux-pumps-in-biofilm-formation
#8
Ilyas Alav, J Mark Sutton, Khondaker Miraz Rahman
Efflux pumps are widely implicated in antibiotic resistance because they can extrude the majority of clinically relevant antibiotics from within cells to the extracellular environment. However, there is increasing evidence from many studies to suggest that the pumps also play a role in biofilm formation. These studies have involved investigating the effects of efflux pump gene mutagenesis and efflux pump inhibitors on biofilm formation, and measuring the levels of efflux pump gene expression in biofilms. In particular, several key pathogenic species associated with increasing multidrug resistance, such as Acinetobacter baumannii, Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus, have been investigated, whilst other studies have focused on Salmonella enterica serovar Typhimurium as a model organism and problematic pathogen...
February 28, 2018: Journal of Antimicrobial Chemotherapy
https://www.readbyqxmd.com/read/29472905/1-2-4-dichlorophenethyl-amino-3-phenoxypropan-2-ol-kills-pseudomonas-aeruginosa-through-extensive-membrane-damage
#9
Valerie Defraine, Veerle Liebens, Evelien Loos, Toon Swings, Bram Weytjens, Carolina Fierro, Kathleen Marchal, Liam Sharkey, Alex J O'Neill, Romu Corbau, Arnaud Marchand, Patrick Chaltin, Maarten Fauvart, Jan Michiels
The ever increasing multidrug-resistance of clinically important pathogens and the lack of novel antibiotics have resulted in a true antibiotic crisis where many antibiotics are no longer effective. Further complicating the treatment of bacterial infections are antibiotic-tolerant persister cells. Besides being responsible for the recalcitrant nature of chronic infections, persister cells greatly contribute to the observed antibiotic tolerance in biofilms and even facilitate the emergence of antibiotic resistance...
2018: Frontiers in Microbiology
https://www.readbyqxmd.com/read/29458656/stress-responses-outer-membrane-permeability-control-and-antimicrobial-resistance-in-enterobacteriaceae
#10
Sushovan Dam, Jean-Marie Pagès, Muriel Masi
Bacteria have evolved several strategies to survive a myriad of harmful conditions in the environment and in hosts. In Gram-negative bacteria, responses to nutrient limitation, oxidative or nitrosative stress, envelope stress, exposure to antimicrobials and other growth-limiting stresses have been linked to the development of antimicrobial resistance. This results from the activation of protective changes to cell physiology (decreased outer membrane permeability), resistance transporters (drug efflux pumps), resistant lifestyles (biofilms, persistence) and/or resistance mutations (target mutations, production of antibiotic modification/degradation enzymes)...
March 2018: Microbiology
https://www.readbyqxmd.com/read/29442016/properties-and-role-of-the-quorum-sensing-molecule-farnesol-in-relation-to-the-yeast-candida-albicans
#11
S Dižová, H Bujdáková
Farnesol is a quorum sensing (QS) molecule synthesized by Candida albicans acting as a negative regulator of morphogenesis; it blocks the yeast-to-hyphae transformation. This molecule is currently studied in particular from the viewpoint of possible use as a substance with anticancer properties and with an antimicrobial, and anti-biofilm effect in yeasts resistant or tolerant to conventional therapeutic agents, for example fluconazole. Besides the aforementioned effect on morphological transformation through cyclic AMP (cAMP)/protein kinase A (cAMP-PKA) pathway, it also affects other biochemical pathways of yeasts, for example those ones for sterol biosynthesis or triggering of apoptosis via accumulation of ROS (reactive oxygen species) that damage essential cellular compartments...
June 1, 2017: Die Pharmazie
https://www.readbyqxmd.com/read/29387173/genome-sequence-and-comparative-genomic-analysis-of-a-clinically-important-strain-cd11-4-of-janibacter-melonis-isolated-from-celiac-disease-patient
#12
Atul Munish Chander, Rakesh Kochhar, Devinder Kumar Dhawan, Sanjay Kumar Bhadada, Shanmugam Mayilraj
Background: Janibacter melonis and other member of this genus are known to cause bacteremia and serious clinical comorbidities, but there is no study reporting about pathogenicity attributes of J. melonis. Janibacter terrae is known to cause lethal infection. Reporting the genome of J. melonis CD11-4 and comparative genomics with other members of genus has provided some novel insights that can enable us to understand the mechanisms responsible for its pathogenicity in humans. Results: Comparative genomic analysis by Rapid Annotation Server and Technology revealed the presence of similar virulence determinant genes in both J...
2018: Gut Pathogens
https://www.readbyqxmd.com/read/29348586/analogues-of-disulfides-from-allium-stipitatum-demonstrate-potent-anti-tubercular-activities-through-drug-efflux-pump-and-biofilm-inhibition
#13
Cynthia A Danquah, Eleftheria Kakagianni, Proma Khondkar, Arundhati Maitra, Mukhlesur Rahman, Dimitrios Evangelopoulos, Timothy D McHugh, Paul Stapleton, John Malkinson, Sanjib Bhakta, Simon Gibbons
Disulfides from Allium stipitatum, commonly known as Persian shallot, were previously reported to possess antibacterial properties. Analogues of these compounds, produced by S-methylthiolation of appropriate thiols using S-methyl methanethiosulfonate, exhibited antimicrobial activity, with one compound inhibiting the growth of Mycobacterium tuberculosis at 17 µM (4 mg L-1 ) and other compounds inhibiting Escherichia coli and multi-drug-resistant (MDR) Staphylococcus aureus at concentrations ranging between 32-138 µM (8-32 mg L-1 )...
January 18, 2018: Scientific Reports
https://www.readbyqxmd.com/read/29325735/whole-transcriptome-analysis-reveals-potential-novel-mechanisms-of-low-level-linezolid-resistance-in-enterococcus-faecalis
#14
Ruoyi Hua, Yun Xia, Wenyao Wu, Jia Yan, Mi Yang
Linezolid is an oxazolidinone antibiotic commonly used to treat serious infections caused by vancomycin-resistant enterococcus. Recently, low-level linezolid resistant Enterococcus faecalis strains have emerged worldwide, but the resistant mechanisms remain undefined. Whole-transcriptome profiling was performed on an E. faecalis strain P10748 with low-level linezolid resistance in comparison with a linezolid-susceptible strain 3138 and the standard control strain ATCC29212. The functions of differentially expressed genes (DEGs) were predicted, with some DEGs potentially involved in drug resistance were validated by PCR and quantitative PCR (qPCR)...
March 20, 2018: Gene
https://www.readbyqxmd.com/read/29311083/aspergillus-fumigatus-afssn3-afssn8-pair-reverse-regulates-azole-resistance-by-conferring-extracellular-polysaccharide-sphingolipid-pathway-intermediates-and-efflux-pumps-to-biofilm
#15
Nanbiao Long, Liping Zeng, Shanlei Qiao, Lei Li, Guowei Zhong
Antifungal treatment is often ineffectual, partly because of biofilm formation. In this study, by using a combined forward and reverse genetic strategy, we identified that nucleus-localized AfSsn3 and its partner AfSsn8, which constitute a Cdk8-cyclin pair, are required for azole resistance in Aspergillus fumigatus Deletion of Afssn3 led to increased absorption and utilization of glucose and amino acids. Interestingly, absorption and utilization of glucose accelerated the extracellular polysaccharide formation, while utilization of the amino acids serine, threonine, and glycine increased sphingolipid pathway intermediate accumulation...
March 2018: Antimicrobial Agents and Chemotherapy
https://www.readbyqxmd.com/read/29180529/the-abc-of-biofilm-drug-tolerance-the-merr-like-regulator-brlr-is-an-activator-of-abc-transport-systems-with-pa1874-77-contributing-to-the-tolerance-of-pseudomonas-aeruginosa-biofilms-to-tobramycin
#16
Bandita Poudyal, Karin Sauer
A hallmark of biofilms is their tolerance to killing by antimicrobial agents. In Pseudomonas aeruginosa , biofilm drug tolerance requires the c-di-GMP-responsive MerR transcriptional regulator BrlR. However, the mechanism by which BrlR mediates biofilm drug tolerance has not been elucidated. Here, we demonstrate that BrlR activates the expression of at least 7 ABC transport systems, including the PA1874-PA1875-PA1876-PA1877 (PA1874-77) operon, with chromatin immunoprecipitation and DNA binding assays confirming BrlR binding to the promoter region of PA1874-77...
February 2018: Antimicrobial Agents and Chemotherapy
https://www.readbyqxmd.com/read/29163396/synergistic-antifungal-effect-of-fluconazole-combined-with-licofelone-against-resistant-candida-albicans
#17
Xinning Liu, Tao Li, Decai Wang, Yilei Yang, Wenwen Sun, Jianqiao Liu, Shujuan Sun
Candida albicans ( C. albicans ) is one of the important opportunistic fungal pathogens that is closely associated with disseminated or chronic infections. The objective of this study is to evaluate the synergistic antifungal effect of licofelone, which is dual microsomal prostaglandin E2 synthase/lipoxygenase (mPGES-1/LOX) inhibitor in combination with fluconazole against C. albicans . Here our results showed that licofelone (16 μg/mL) can synergistically work with fluconazole (1 μg/mL) against planktonic cells of fluconazole-resistant C...
2017: Frontiers in Microbiology
https://www.readbyqxmd.com/read/29095142/high-mortality-of-bloodstream-infection-outbreak-caused-by-carbapenem-resistant-p-aeruginosa-producing-spm-1-in-a-bone-marrow-transplant-unit
#18
Lucas Chaves, Lísia Moura Tomich, Matias Salomão, Gleice Cristina Leite, Jessica Ramos, Roberta Ruedas Martins, Camila Rizek, Patricia Neves, Marjorie Vieira Batista, Ulysses Amigo, Thais Guimaraes, Anna Sara Levin, Silvia Figueiredo Costa
PURPOSE: Carbapenem resistance in P. aeruginosa is increasing worldwide. In Brazil, SPM-1 is the main P. aeruginosa carbapenemase identified. Little is known about the virulence factor in SPM-1 clones.Methodolgy. We describe a carbapenem-resistant P. aeruginosa bloodstream infection (CRPa-BSI) outbreak in a bone marrow transplant Unit (BMT). Twenty-nine CRPa-BSI cases were compared to 58 controls. Microbiological characteristics of isolates, such as sensitivity, carbapenemase gene PCR for P...
December 2017: Journal of Medical Microbiology
https://www.readbyqxmd.com/read/29046665/boeravinone-b-a-novel-dual-inhibitor-of-nora-bacterial-efflux-pump-of-staphylococcus-aureus-and-human-p-glycoprotein-reduces-the-biofilm-formation-and-intracellular-invasion-of-bacteria
#19
Samsher Singh, Nitin P Kalia, Prashant Joshi, Ajay Kumar, Parduman R Sharma, Ashok Kumar, Sandip B Bharate, Inshad A Khan
This study elucidated the role of boeravinone B, a NorA multidrug efflux pump inhibitor, in biofilm inhibition. The effects of boeravinone B plus ciprofloxacin, a NorA substrate, were evaluated in NorA-overexpressing, wild-type, and knocked-out Staphylococcus aureus (SA-1199B, SA-1199, and SA-K1758, respectively). The mechanism of action was confirmed using the ethidium bromide accumulation and efflux assay. The role of boeravinone B as a human P -glycoprotein ( P -gp) inhibitor was examined in the LS-180 (colon cancer) cell line...
2017: Frontiers in Microbiology
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
#20
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
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