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biofilm and efflux pump

A Klančnik, M Šikić Pogačar, K Trošt, M Tušek Žnidarič, B Mozetič Vodopivec, S Smole Možina
AIMS: To define anti-Campylobacter jejuni activity of an extract from waste skins and seeds of Pinot noir grapes (GSS) and of resveratrol, and possible resistance mechanisms, and the influence of these on C. jejuni morphology. METHODS AND RESULTS: Using gene-specific knock-out C. jejuni mutants and an efflux-pump inhibitor, we show CmeABC as the most active efflux pump for extrusion across the outer membrane of GSS extract and resveratrol. Using polystyrene and pig small-intestine epithelial (PSI) and human foetal small intestine (H4) cell lines, GSS extract shows efficient inhibition of adhesion of C...
October 6, 2016: Journal of Applied Microbiology
Nopphasul Sirijant, Rasana W Sermswan, Surasakdi Wongratanacheewin
Burkholderia pseudomallei, the causative agent of melioidosis, has been found to increase its resistance to antibiotics when growing as a biofilm. The resistances are related to several mechanisms. One of the possible mechanisms is the efflux pump. Using bioinformatics analysis, it was found that BPSL1661, BPSL1664 and BPSL1665 were orthologous genes of the efflux transporter encoding genes for biofilm related antibiotic resistance PA1874-PA1877 genes in Pseudomonas aeruginosa strain PAO1. Expressions of selected encoding genes for the efflux transporter system during biofilm formation were investigated...
September 30, 2016: Journal of Medical Microbiology
Ying Li, Sanjie Cao, Luhua Zhang, Jianlin Yuan, Gee W Lau, Yiping Wen, Rui Wu, Qin Zhao, Xiaobo Huang, Qigui Yan, Yong Huang, Xintian Wen
Actinobacillus pleuropneumoniae is the etiologic agent of porcine contagious pleuropneumonia, a major cause of economic loss in swine industry worldwide. TolC, the key component of multidrug efflux pumps and type I secretion systems, has been well-studied as an exit duct for numerous substances in many Gram-negative bacteria. By contrast, little is known on the role of TolC in biofilm formation. In this study, a ΔtolC mutant was used to examine the importance of TolC in biofilm formation of A. pleuropneumoniae...
2016: PloS One
Atin Sharma, Rajnikant Sharma, Tapas Bhattacharyya, Timsy Bhando, Ranjana Pathania
OBJECTIVES: To decipher the function of A1S_1331, named AbaF (Acinetobacter baumannii Fosfomycin efflux), one of the primary targets of AbsR25, a small RNA of A. baumannii. METHODS: abaF was cloned in a multicopy plasmid and expressed from its native promoter in an efflux-deficient strain-Escherichia coli KAM32. Drug susceptibility, accumulation and efflux of ethidium bromide (EtBr) were determined in this strain. abaF was disrupted in A. baumannii using homologous recombination and its effect on drug susceptibility, biofilm formation and virulence was studied...
September 20, 2016: Journal of Antimicrobial Chemotherapy
Ana Cristina Abreu, Maria José Saavedra, Lúcia C Simões, Manuel Simões
Combinations of selected phytochemicals (reserpine, pyrrolidine, quinine, morin and quercetin) with antibiotics (ciprofloxacin, tetracycline and erythromycin) were tested on the prevention and control of Staphylococcus aureus biofilms. The phytochemicals were also studied for their ability to avoid antibiotic adaptation and to inhibit antibiotic efflux pumps. Morin, pyrrolidine and quercetin at subinhibitory concentrations had significant effects in biofilm prevention and/or control when applied alone and combined with antibiotics...
October 2016: Biofouling
Hafiz Ghulam Murtaza Saleem, Christine Ann Seers, Anjum Nasim Sabri, Eric Charles Reynolds
BACKGROUND: Chlorhexidine (CHX) is used in oral care products to help control dental plaque. In this study dental plaque bacteria were grown on media containing 2 μg/ml chlorhexidine gluconate to screen for bacteria with reduced CHX susceptibility. The isolates were characterized by 16S rRNA gene sequencing and antibiotic resistance profiles were determined using the disc diffusion method. RESULTS: The isolates were variably resistant to multiple drugs including ampicillin, kanamycin, gentamicin and tetracycline...
2016: BMC Microbiology
Rosa van Mansfeld, Mark de Been, Fernanda Paganelli, Lei Yang, Marc Bonten, Rob Willems
This study investigates adaptation of ST406, a prevalent P. aeruginosa clone, present in 15% of chronically infected cystic fibrosis (CF) patients in the Netherlands, in a newly infected CF patient during three years using whole genome sequencing (WGS), transcriptomics, and phenotypic assays, including biofilm formation. WGS-based phylogeny demonstrates that ST406 is genetically distinct from other reported CF related strains or epidemic clones. Comparative genomic analysis of the early (S1) and late (S2) isolate yielded 42 single nucleotide polymorphisms (SNPs) and 10 indels and a single 7 kb genomic fragment only found in S2...
2016: PloS One
Hassan Sakhtah, Leslie Koyama, Yihan Zhang, Diana K Morales, Blanche L Fields, Alexa Price-Whelan, Deborah A Hogan, Kenneth Shepard, Lars E P Dietrich
Redox-cycling compounds, including endogenously produced phenazine antibiotics, induce expression of the efflux pump MexGHI-OpmD in the opportunistic pathogen Pseudomonas aeruginosa Previous studies of P. aeruginosa virulence, physiology, and biofilm development have focused on the blue phenazine pyocyanin and the yellow phenazine-1-carboxylic acid (PCA). In P. aeruginosa phenazine biosynthesis, conversion of PCA to pyocyanin is presumed to proceed through the intermediate 5-methylphenazine-1-carboxylate (5-Me-PCA), a reactive compound that has eluded detection in most laboratory samples...
June 21, 2016: Proceedings of the National Academy of Sciences of the United States of America
Kaat De Cremer, Katrijn De Brucker, Ines Staes, Annelies Peeters, Freija Van den Driessche, Tom Coenye, Bruno P A Cammue, Karin Thevissen
We performed a whole-transcriptome analysis of miconazole-treated Candida albicans biofilms, using RNA-sequencing. Our aim was to identify molecular pathways employed by biofilm cells of this pathogen to resist action of the commonly used antifungal miconazole. As expected, genes involved in sterol biosynthesis and genes encoding drug efflux pumps were highly induced in biofilm cells upon miconazole treatment. Other processes were affected as well, including the electron transport chain (ETC), of which eight components were transcriptionally downregulated...
2016: Scientific Reports
Eun-Jeong Yoon, Viviane Balloy, Laurence Fiette, Michel Chignard, Patrice Courvalin, Catherine Grillot-Courvalin
UNLABELLED: Overexpression of chromosomal resistance-nodulation-cell division (RND)-type efflux systems with broad substrate specificity contributes to multidrug resistance (MDR) in Acinetobacter baumannii We have shown that modulation of expression of the structural genes for the efflux systems AdeABC and AdeIJK confers MDR and results in numerous alterations of membrane-associated cellular functions, in particular biofilm formation. However, the contribution of these RND pumps to cell fitness and virulence has not yet been studied...
2016: MBio
Yongbin Xu, Jianyun Guo, Lulu Wang, Rui Jiang, Xiaoling Jin, Jing Liu, Shengdi Fan, Chun-Shan Quan, Nam-Chul Ha
Bacillus possesses the peptide toxin Sporulation-Delaying Protein (SDP), which can kill cells within a biofilm to support continued growth, thereby delaying the onset of biofilm sporulation. The four-component transporter YknWXYZ acts as a major SDP efflux pump to protect cells against the endogenous SDP toxin, for which YknYZ is a non-canonical ATP-binding cassette (ABC)-type transporter. YknYZ consists of the following two components: (1) an individual protein (YknY) and (2) a respective permease (YknZ). To date, the crystal structure, molecular function, and mechanism of action of the integral membrane protein YknZ remain to be elucidated...
2016: PloS One
Arianna Pompilio, Valentina Crocetta, Fabio Verginelli, Giovanni Di Bonaventura
The activity of levofloxacin against planktonic and biofilm Stenotrophomonas maltophilia cells and the role played by the multidrug efflux pump SmeDEF were evaluated under conditions relevant to the cystic fibrosis (CF) lung. MIC, MBC and MBEC of levofloxacin were assessed, against five CF strains, under 'standard' (CLSI-recommended) and 'CF-like' (pH 6.8, 5% CO2, in a synthetic CF sputum) conditions. Levofloxacin was tested against biofilms at concentrations (10, 50 and 100 μg mL(-1)) corresponding to achievable serum levels and sputum levels by aerosolisation...
July 2016: FEMS Microbiology Letters
Katja Bezek, Marija Kurinčič, Elvira Knauder, Anja Klančnik, Peter Raspor, Franz Bucar, Sonja Smole Možina
Thermophilic campylobacters are a major cause of bacterial food-borne diarrhoeal disease. Adherence and biofilm formation are key elements of Campylobacter jejuni persistence in unfavourable environmental conditions. The phytochemical analysis of Euodia ruticarpa fruit ethanol solution extract (EREE) indicated that the major compounds were evodiamine (1), rutaecarpine (2) and evocarpine (9). E. ruticarpa fruit ethanol solution extract, compounds 1 and 2 as well as a mixture of quinolinone alkaloids with 41...
September 2016: Phytotherapy Research: PTR
Ankita Bansal, Dhriti Mallik, Debasish Kar, Anindya S Ghosh
Cell wall impermeability and active efflux of drugs are among the primary reasons for drug resistance in mycobacteria. Efflux pumps are tripartite membrane localized transport proteins that expel drug molecules outside the cells. Several of such efflux pumps are annotated in mycobacteria, but few have been characterized, like MSMEG_2991, a putative efflux pump permease of Mycobacterium smegmatis To substantiate this, we overexpressed MSMEG_2991 protein in Escherichia coli 2443. Expression of MSMEG_2991 elevated the resistance towards structurally unrelated groups of antibiotics...
July 2016: FEMS Microbiology Letters
Sha Zheng, Wenqiang Chang, Chen Li, Hongxiang Lou
Copper surfaces possess efficient antimicrobial effect. Here, we reported that copper surfaces could inactivate Candida albicans biofilms within 40 min. The intracellular reactive oxygen species in C. albicans biofilms were immediately stimulated during the contact of copper surfaces, which might be an important factor for killing the mature biofilms. Copper release assay demonstrated that the copper ions automatically released from the surface of 1 mm thick copper coupons with over 99.9% purity are not the key determinant for the copper-mediated killing action...
May 2016: FEMS Yeast Research
Carlos F Amábile-Cuevas
Aerosolized amikacin reaches high concentrations in lung fluids, which are well above the minimum inhibitory concentrations (MICs) of resistant strains of Pseudomonas aeruginosa. However, P. aeruginosa can gain resistance to amikacin through different cumulative mechanisms; amikacin MICs are seldom reported beyond values of 1,000 μg/ml, as tested in clinical microbiology assays. To assess how high amikacin MICs can be reached by graded exposure, four amikacin-resistant P. aeruginosa isolates were grown in a 4-step increased exposure to amikacin; derivative strains were further characterized by measuring their comparative growth rate, biofilm-forming ability, and susceptibility to other antibiotics...
May 16, 2016: Microbial Drug Resistance: MDR: Mechanisms, Epidemiology, and Disease
Norma M Allewell
The biofilms that many bacteria and fungi produce enable them to form communities, adhere tightly to surfaces, evade host immunity, and resist antibiotics. Pathogenic microorganisms that form biofilms are very difficult to eradicate and thus are a frequent source of life-threatening, hospital-acquired infections. This series of five minireviews from the Journal of Biological Chemistry provides a broad overview of our current understanding of biofilms and the challenges that remain. The structure, biosynthesis, and biological function of the biofilms produced by pathogenic fungi are the subject of the first article, by Sheppard and Howell...
June 10, 2016: Journal of Biological Chemistry
Elisa Borghi, Francesca Borgo, Giulia Morace
Over the past decade, the emergence of biofilm-related invasive fungal diseases has been the subject of numerous studies focused on antifungal resistance and its impact on antifungal therapy in severely ill patients. The majority of the studies investigated the molecular mechanisms involved in antifungal resistance and pathogenicity of biofilm production by Candida albicans and Aspergillus fumigatus, the most common etiologic agents of yeast and mold invasive infections. The main mechanism characterizing biofilm-related antifungal resistance is the production of extracellular matrix, a physical barrier preventing the drugs from entering and expressing their activity...
2016: Advances in Experimental Medicine and Biology
Santiago Sandoval-Motta, Maximino Aldana
Despite all the major breakthroughs in antibiotic development and treatment procedures, there is still no long-term solution to the bacterial antibiotic resistance problem. Among all the known types of resistance, adaptive resistance (AdR) is particularly inconvenient. This phenotype is known to emerge as a consequence of concentration gradients, as well as contact with subinhibitory concentrations of antibiotics, both known to occur in human patients and livestock. Moreover, AdR has been repeatedly correlated with the appearance of multidrug resistance, although the biological processes behind its emergence and evolution are not well understood...
May 2016: Wiley Interdisciplinary Reviews. Systems Biology and Medicine
Grace E Richmond, Laura P Evans, Michele J Anderson, Matthew E Wand, Laura C Bonney, Alasdair Ivens, Kim Lee Chua, Mark A Webber, J Mark Sutton, Marnie L Peterson, Laura J V Piddock
UNLABELLED: The opportunistic pathogen Acinetobacter baumannii is able to persist in the environment and is often multidrug resistant (MDR), causing difficulties in the treatment of infections. Here, we show that the two-component system AdeRS, which regulates the production of the AdeABC multidrug resistance efflux pump, is required for the formation of a protective biofilm in an ex vivo porcine mucosal model, which mimics a natural infection of the human epithelium. Interestingly, deletion of adeB impacted only on the ability of strain AYE to form a biofilm on plastic and only on the virulence of strain Singapore 1 for Galleria mellonella RNA-Seq revealed that loss of AdeRS or AdeB significantly altered the transcriptional landscape, resulting in the changed expression of many genes, notably those associated with antimicrobial resistance and virulence interactions...
2016: MBio
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