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biofilm and efflux pump

Denice C Bay, Carol A Stremick, Carmine J Slipski, Raymond J Turner
Escherichia coli possesses many secondary active multidrug resistance transporters (MDTs) that confer overlapping substrate resistance to a broad range of antimicrobials via proton and/or sodium motive force. It is uncertain whether redundant MDTs uniquely alter cell survival when cultures grow planktonically or as biofilms. In this study, the planktonic and biofilm growth and antimicrobial resistance of 13 E. coli K-12 single MDT gene deletion strains in minimal and rich media were determined. Antimicrobial tolerance to tetracycline, tobramycin and benzalkonium were also compared for each ΔMDT strain...
November 22, 2016: Research in Microbiology
Masato Inaba, Naoyuki Matsuda, Hirotsugu Banno, Wanchun Jin, Jun-Ichi Wachino, Keiko Yamada, Kouji Kimura, Yoshichika Arakawa
The host stress hormone norepinephrine (NE), also called noradrenaline, is reported to augment bacterial growth and pathogenicity, but few studies have focused on the effect of NE on the activity of antimicrobials. The aim of this study was to clarify whether NE affects antimicrobial activity against multidrug-resistant Acinetobacter baumannii (MDR-AB). Time-kill studies of tigecycline (TIG) and colistin (COL) against MDR-AB as well as assays for factors contributing to antibiotic resistance were performed using MDR-AB clinical strains both in the presence and absence of 10 µM NE...
November 4, 2016: International Journal of Antimicrobial Agents
Huale Chen, Jianming Cao, Cui Zhou, Haiyang Liu, Xiaoxiao Zhang, Tieli Zhou
BACKGROUND: Tigecycline, one of the few therapeutic options against multidrug-resistant Acinetobacter baumannii, reaches subinhibitory serum concentrations only with cautious clinical dosing and pharmacokinetics. Subinhibitory concentrations of tigecycline might induce an A. baumannii biofilm. METHODS: Biofilm formation was assessed via the crystal violet staining method. We further analyzed the main biofilm components with NaIO4, proteinase K, and DNase. Real-time RT-PCR was applied for quantitative detection of biofilm potential-associated genes...
November 5, 2016: Chemotherapy
Chen Yufan, Liu Shiyin, Liang Zhibin, Lv Mingfa, Zhou Jianuan, Zhang Lianhui
Microbial drug resistance has become a serious problem of global concern, and the evolution and regulatory mechanisms of microbial drug resistance has become a hotspot of research in recent years. Recent studies showed that certain microbial resistance mechanisms are regulated by quorum sensing system. Quorum sensing is a ubiquitous cell-cell communication system in the microbial world, which associates with cell density. High-density microbial cells produce sufficient amount of small signal molecules, activating a range of downstream cellular processes including virulence and drug resistance mechanisms, which increases bacterial drug tolerance and causes infections on host organisms...
October 20, 2016: Yi Chuan, Hereditas
Oluwaseun Ayodeji Ishola, Seng Yeat Ting, Yasser M Tabana, Mowaffaq Adam Ahmed, Muhammad Amir Yunus, Rafeezul Mohamed, Leslie Thian Lung Than, Doblin Sandai
BACKGROUND: A major characteristic of Candida biofilm cells that differentiates them from free-floating cells is their high tolerance to antifungal drugs. This high resistance is attributed to particular biofilm properties, including the accumulation of extrapolymeric substances, morphogenetic switching, and metabolic flexibility. OBJECTIVES: This study evaluated the roles of metabolic processes (in particular the glyoxylate cycle) on biofilm formation, antifungal drug resistance, morphology, and cell wall components...
September 2016: Jundishapur Journal of Microbiology
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 resistance is 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. Expression of selected encoding genes for the efflux transporter system during biofilm formation were investigated...
November 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...
September 15, 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
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