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biofilm and efflux pump

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https://www.readbyqxmd.com/read/28437232/epidemiological-physiological-and-molecular-characteristics-of-a-brazilian-collection-of-carbapenem-resistant-acinetobacter-baumannii-and-pseudomonas-aeruginosa
#1
Vanessa Cordeiro Dias, Juliana Alves Resende, André Netto Bastos, Lucas Quinet De Andrade Bastos, Victor Quinet De Andrade Bastos, Ricardo Villela Bastos, Cláudio Galuppo Diniz, Vânia Lúcia Da Silva
Nonfermenting Gram-negative bacteria such as Pseudomonas aeruginosa and Acinetobacter baumannii are widespread in the environment and are increasingly associated with nosocomial infections, often associated with multidrug-resistance phenotypes. This study aimed to evaluate epidemiological, physiological, and molecular characteristics of carbapenem resistance in P. aeruginosa and A. baumannii. In total, 63 nonreplicated strains (44 A. baumannii and 19 P. aeruginosa) were isolated from hospitalized patients. Antimicrobial resistance patterns, biocide tolerance, oxidative stress, hemolytic activity, and biofilm formation were assessed...
February 24, 2017: Microbial Drug Resistance: MDR: Mechanisms, Epidemiology, and Disease
https://www.readbyqxmd.com/read/28436748/disruption-of-tetr-type-regulator-aden-by-mobile-genetic-element-confers-elevated-virulence-in-acinetobacter-baumannii
#2
Rajagopalan Saranathan, Sudhakar Pagal, Ajit R Sawant, Archana Tomar, M Madhangi, Suresh Sah, Annapurna Satti, K P Arunkumar, K Prashanth
Acinetobacter baumannii is an important human pathogen and considered as a major threat due to its extreme drug resistance. In this study, the genome of a hyper-virulent MDR strain PKAB07 of A. baumannii isolated from an Indian patient was sequenced and analysed to understand its mechanisms of virulence, resistance and evolution. Comparative genomics analysis of PKAB07 revealed virulence and resistance related genes scattered throughout the genome, instead of being organized as an island, indicating the highly mosaic nature of the genome...
April 24, 2017: Virulence
https://www.readbyqxmd.com/read/28348056/analysis-of-shigella-flexneri-resistance-biofilm-formation-and-transcriptional-profile-in-response-to-bile-salts
#3
Kourtney P Nickerson, Rachael B Chanin, Jeticia R Sistrunk, David A Rasko, Peter J Fink, Eileen M Barry, James P Nataro, Christina S Faherty
The Shigella species cause millions of cases of watery or bloody diarrhea each year, mostly in children in developing countries. While many aspects of Shigella colonic cell invasion are known, crucial gaps in knowledge remain regarding how the bacteria survive, transit, and regulate gene expression prior to infection. In this study, we define mechanisms of bile salts resistance and build on previous research highlighting induced virulence in S. flexneri strain 2457T following bile salts exposure. Typical growth patterns were observed within the physiological range of bile salts; however, growth was inhibited at higher concentrations...
March 27, 2017: Infection and Immunity
https://www.readbyqxmd.com/read/28289081/light-modulates-metabolic-pathways-and-other-novel-physiological-traits-in-the-human-pathogen-acinetobacter-baumannii
#4
Gabriela L Müller, Marisel Tuttobene, Matías Altilio, Maitena Martinez Amezaga, Meaghan Nguyen, P Pamela Cribb, Larisa E Cybulski, María Soledad Ramírez, Silvia Altabe, María Alejandra Mussi
Light sensing in chemotrophic bacteria has been relatively recently ascertained. In the human pathogen Acinetobacter baumannii, light modulates motility, biofilm formation and virulence through the BLUF photoreceptor BlsA. In addition, light can induce reduction in susceptibility to certain antibiotics such as minocycline and tigecycline in a photoreceptor-independent manner. In this work we identified new traits whose expression are modulated by light in this pathogen, which comprise not only important determinants related to pathogenicity and antibiotic resistance, but also metabolic pathways, which represents a novel concept for chemotrophic bacteria...
March 13, 2017: Journal of Bacteriology
https://www.readbyqxmd.com/read/28275296/effect-of-biofilm-formation-by-clinical-isolates-of-helicobacter-pylori-on-the-efflux-mediated-resistance-to-commonly-used-antibiotics
#5
Bahareh Attaran, Tahereh Falsafi, Nassim Ghorbanmehr
AIM: To evaluate the role of biofilm formation on the resistance of Helicobacter pylori (H. pylori) to commonly prescribed antibiotics, the expression rates of resistance genes in biofilm-forming and planktonic cells were compared. METHODS: A collection of 33 H. pylori isolates from children and adult patients with chronic infection were taken for the present study. The isolates were screened for biofilm formation ability, as well as for polymerase chain reaction (PCR) reaction with HP1165 and hp1165 efflux pump genes...
February 21, 2017: World Journal of Gastroenterology: WJG
https://www.readbyqxmd.com/read/28270804/eradication-and-sensitization-of-methicillin-resistant-staphylococcus-aureus-to-methicillin-with-bioactive-extracts-of-berry-pomace
#6
Serajus Salaheen, Mengfei Peng, Jungsoo Joo, Hironori Teramoto, Debabrata Biswas
The therapeutic roles of phenolic blueberry (Vaccinium corymbosum) and blackberry (Rubus fruticosus) pomace (commercial byproduct) extracts (BPE) and their mechanism of actions were evaluated against methicillin resistant Staphylococcus aureus (MRSA). Five major phenolic acids of BPE, e.g., protocatechuic, p. coumaric, vanillic, caffeic, and gallic acids, as well as crude BPE completely inhibited the growth of vegetative MRSA in vitro while BPE+methicillin significantly reduced MRSA biofilm formation on plastic surface...
2017: Frontiers in Microbiology
https://www.readbyqxmd.com/read/28138373/resistance-of-candida-albicans-biofilms-to-drugs-and-the-host-immune-system
#7
REVIEW
Doblin Sandai, Yasser M Tabana, Ahmad El Ouweini, Ishola Oluwaseun Ayodeji
BACKGROUND: Candida albicans is a commensal fungus that resides on mucosal surfaces and in the gastrointestinal and genitourinary tracts in humans. However, it can cause an infection when the immune system of the host is impaired or if a niche becomes available. Many C. albicans infections are due to the organism's ability to form a biofilm on implanted medical devices. A biofilm represents an optimal medium for the growth of C. albicans as it allows cells to be enclosed by a self-produced extracellular matrix (ECM)...
November 2016: Jundishapur Journal of Microbiology
https://www.readbyqxmd.com/read/28062292/use-of-carvacrol-thymol-and-eugenol-for-biofilm-eradication-and-resistance-modifying-susceptibility-of-salmonella-enterica-serovar-typhimurium-strains-to-nalidixic-acid
#8
Hanene Miladi, Tarek Zmantar, Bochra Kouidhi, Yassine Chaabouni, Kacem Mahdouani, Amina Bakhrouf, Kamel Chaieb
The Aims of the study was to evaluate the antibacterial susceptibility and the biofilm eradication of three natural compounds carvacrol (CAR), thymol (TH) and eugenol (EUG), alone or in combination with nalidixic acid (NA) against twelve Salmonella Typhimurium strains. The minimum inhibitory concentration (MIC) and the minimum biofilm eradication concentration (BEC50) of the tested compounds (CAR, TH and EUG) and their combinations with NA were evaluated. In order to assess whether these bacteria had active efflux pumps, ethidium bromide (EtBr) accumulation assays was achieved using spectrophotometric accumulation assays...
March 2017: Microbial Pathogenesis
https://www.readbyqxmd.com/read/27986731/novel-cadmium-resistance-determinant-in-listeria-monocytogenes
#9
Cameron Parsons, Sangmi Lee, Victor Jayeola, Sophia Kathariou
Listeria monocytogenes is a foodborne pathogen that can cause severe disease (listeriosis) in susceptible individuals. It is ubiquitous in the environment and often exhibits resistance to heavy metals. One of the determinants that enables Listeria to tolerate exposure to cadmium is the cadAC efflux system, with CadA being a P-type ATPase. Three different cadA genes (designated cadA1 to cadA3) were previously characterized in L. monocytogenes A novel putative cadmium resistance gene (cadA4) was recently identified through whole-genome sequencing, but experimental confirmation for its involvement in cadmium resistance is lacking...
March 1, 2017: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/27936915/promethazine-improves-antibiotic-efficacy-and-disrupts-biofilms-of-burkholderia-pseudomallei
#10
José Júlio Costa Sidrim, David Caldas Vasconcelos, Giovanna Barbosa Riello, Glaucia Morgana de Melo Guedes, Rosana Serpa, Tereza de Jesus Pinheiro Gomes Bandeira, André Jalles Monteiro, Rossana de Aguiar Cordeiro, Débora de Souza Collares Maia Castelo-Branco, Marcos Fábio Gadelha Rocha, Raimunda Sâmia Nogueira Brilhante
Efflux pumps are important defense mechanisms against antimicrobial drugs and maintenance of Burkholderia pseudomallei biofilms. This study evaluated the effect of the efflux pump inhibitor promethazine on the structure and antimicrobial susceptibility of B. pseudomallei biofilms. Susceptibility of planktonic cells and biofilms to promethazine alone and combined with antimicrobials was assessed by the broth microdilution test and biofilm metabolic activity was determined with resazurin. The effect of promethazine on 48 h-grown biofilms was also evaluated through confocal and electronic microscopy...
January 2017: Biofouling
https://www.readbyqxmd.com/read/27884783/secondary-multidrug-efflux-pump-mutants-alter-escherichia-coli-biofilm-growth-in-the-presence-of-cationic-antimicrobial-compounds
#11
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...
April 2017: Research in Microbiology
https://www.readbyqxmd.com/read/27842757/in-vitro-reduction-of-antibacterial-activity-of-tigecycline-against-multidrug-resistant-acinetobacter-baumannii-with-host-stress-hormone-norepinephrine
#12
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...
December 2016: International Journal of Antimicrobial Agents
https://www.readbyqxmd.com/read/27816975/biofilm-formation-restrained-by-subinhibitory-concentrations-of-tigecyclin-in-acinetobacter-baumannii-is-associated-with-downregulation-of-efflux-pumps
#13
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...
2017: Chemotherapy
https://www.readbyqxmd.com/read/27806929/quorum-sensing-and-microbial-drug-resistance
#14
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
https://www.readbyqxmd.com/read/27800147/the-role-of-isocitrate-lyase-icl1-in-the-metabolic-adaptation-of-candida-albicans-biofilms
#15
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
https://www.readbyqxmd.com/read/27709726/anti-campylobacter-activity-of-resveratrol-and-an-extract-from-waste-pinot-noir-grape-skins-and-seeds-and-resistance-of-camp-%C3%A2-jejuni-planktonic-and-biofilm-cells-mediated-via-the-cmeabc-efflux-pump
#16
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), resveratrol and possible resistance mechanisms, and the influence of these on Camp. jejuni morphology. METHODS AND RESULTS: Using gene-specific knock-out Camp. jejuni mutants and an efflux pump inhibitor, we showed CmeABC as the most active efflux pump for extrusion across the outer membrane of GSS extract and resveratrol. Using polystyrene surface and pig small intestine epithelial (PSI) and human foetal small intestine (H4) cell lines, GSS extract shows an efficient inhibition of adhesion of Camp...
January 2017: Journal of Applied Microbiology
https://www.readbyqxmd.com/read/27702426/burkholderia-pseudomallei-resistance-to-antibiotics-in-biofilm-induced-conditions-is-related-to-efflux-pumps
#17
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
https://www.readbyqxmd.com/read/27681876/absence-of-tolc-impairs-biofilm-formation-in-actinobacillus-pleuropneumoniae-by-reducing-initial-attachment
#18
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
https://www.readbyqxmd.com/read/27650185/fosfomycin-resistance-in-acinetobacter-baumannii-is-mediated-by-efflux-through-a-major-facilitator-superfamily-mfs-transporter-abaf
#19
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...
January 2017: Journal of Antimicrobial Chemotherapy
https://www.readbyqxmd.com/read/27643487/combinatorial-approaches-with-selected-phytochemicals-to-increase-antibiotic-efficacy-against-staphylococcus-aureus-biofilms
#20
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
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