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Olivier Poupel, Caroline Proux, Bernd Jagla, Tarek Msadek, Sarah Dubrac
The success of Staphylococcus aureus, as both a human and animal pathogen, stems from its ability to rapidly adapt to a wide spectrum of environmental conditions. Two-component systems (TCSs) play a crucial role in this process. Here, we describe a novel staphylococcal virulence factor, SpdC, an Abi-domain protein, involved in signal sensing and/or transduction. We have uncovered a functional link between the WalKR essential TCS and the SpdC Abi membrane protein. Expression of spdC is positively regulated by the WalKR system and, in turn, SpdC negatively controls WalKR regulon genes, effectively constituting a negative feedback loop...
March 2018: PLoS Pathogens
Quintin Borgersen, David T Bolick, Glynis L Kolling, Matthew Aijuka, Fernando Ruiz-Perez, Richard L Guerrant, James P Nataro, Araceli E Santiago
Enteroaggregative E. coli (EAEC) is associated with food-borne outbreaks of diarrhea and growth faltering among children in developing countries. A Shiga toxin-producing EAEC strain of serotype O104:H4 strain caused one of the largest outbreaks of a food-borne infection in Europe in 2011. The outbreak was traced to contaminated fenugreek sprouts, yet the mechanisms whereby such persistent contamination of sprouts could have occurred are not clear. We found that under ambient conditions of temperature and in minimal media, pathogenic Shiga toxin-producing EAEC O104:H4 227-11 and non-Shiga toxin-producing 042 strains both produce high levels of exopolysaccharide structures (EPS) that are released to the external milieu...
March 15, 2018: Gut Microbes
Rajendra H Patil, Firoz A Kalam Khan, Kaivalya Jadhav, Manoj Damale, Siddique Akber Ansari, Hamad M Alkahtani, Azmat Ali Khan, Shantanu D Shinde, Rajesh Patil, Jaiprakash N Sangshetti
We report the synthesis of some new piperazine-sulphonamide linked Schiff bases as fungal biofilm inhibitors with antibacterial and antifungal potential. The biofilm inhibition result of Candida albicans proposed that the compounds 6b (IC50  = 32.1 μM) and 6j (IC50  = 31.4 μM) showed higher inhibitory activity than the standard fluconazole (IC50  = 40 μM). Compound 6d (MIC = 26.1 μg/mL) with a chloro group at the para position was found to be the most active antibacterial agent of the series against Bacillus subtilis when compared with the standard ciprofloxacin (MIC = 50 μg/mL)...
March 15, 2018: Archiv der Pharmazie
Neerupma Bhardwaj, Kirtimaan Syal, Dipankar Chatterji
ppGpp, an alarmone for stringent response, plays an important role in the reprogramming of the transcription complex at the time of stress. In Escherichia coli, ppGpp mediates its action by binding to at least two different sites on RNA polymerase (RNAP). One of the sites to which ppGpp binds to RNAP is at the β'-ω interface; however, the underlying molecular mechanism and the physiological relevance of ppGpp binding to this site remain unclear. In this study, we have performed UV cross-linking experiments using32 P azido-labeled ppGpp to probe its association with RNAP in the absence and presence of ω, and observed weaker binding of ppGpp to the RNAP without ω...
March 15, 2018: Genes to Cells: Devoted to Molecular & Cellular Mechanisms
Brijesh Kumar, John L Sorensen, Silvia T Cardona
Burkholderia cenocepacia is an opportunistic bacterium that can thrive in different environments, including the amino acid-rich mucus of the cystic fibrosis (CF) lung. B. cenocepacia responds to the nutritional conditions that mimic the CF sputum by increasing flagellin expression and swimming motility. Individual amino acids also induce swimming but not flagellin expression. Here, we show that modulation of the second messenger cyclic dimeric guanosine monophosphate (c-di-GMP) levels by the PAS-containing c-di-GMP phosphodiesterase, BCAL1069 (CdpA), regulates the swimming motility of B...
2018: Frontiers in Cellular and Infection Microbiology
Katherine Y Le, Matthew D Park, Michael Otto
The primary virulence factor of the skin commensal and opportunistic pathogen, Staphylococcus epidermidis , is the ability to form biofilms on surfaces of implanted materials. Much of this microorganism's pathogenic success has been attributed to its ability to evade the innate immune system. The primary defense against S. epidermidis biofilm infection consists of complement activation, recruitment and subsequent killing of the pathogen by effector cells. Among pathogen-derived factors, the biofilm exopolysaccharide polysaccharide intercellular adhesion (PIA), as well as the accumulation-associated protein (Aap), and the extracellular matrix binding protein (Embp) have been shown to modulate effector cell-mediated killing of S...
2018: Frontiers in Microbiology
Leron Khalifa, Daniel Gelman, Mor Shlezinger, Axel Lionel Dessal, Shunit Coppenhagen-Glazer, Nurit Beyth, Ronen Hazan
The deteriorating effectiveness of antibiotics is propelling researchers worldwide towards alternative techniques such as phage therapy: curing infectious diseases using viruses of bacteria called bacteriophages. In a previous paper, we isolated phage EFDG1, highly effective against both planktonic and biofilm cultures of one of the most challenging pathogenic species, the vancomycin-resistant Enterococcus (VRE). Thus, it is a promising phage to be used in phage therapy. Further experimentation revealed the emergence of a mutant resistant to EFDG1 phage: EFDG1r ...
2018: Frontiers in Microbiology
Qian Liu, Yang Yang, Xiaoxue Mei, Bingfeng Liu, Chuan Chen, Defeng Xing
Ferric iron can affect the current generation of microbial electrochemical system (MES); however, how it influences microbial biofilm formation and metabolic activity has not been reported. Here, we describe the response of microbial electrode biofilm communities to insoluble ferric iron (Fe3+ ) at different concentrations in microbial fuel cells (MFCs). Insoluble ferric iron (200μM) improved electrochemical activity of the MFCs microbial biofilms during start-up and resulted in a higher maximum power density of 0...
March 11, 2018: Science of the Total Environment
Hui Sun, Yuanxiu Hong, Yuejing Xi, Yijie Zou, Jingyi Gao, Jianzhong Du
Antimicrobial peptides (AMPs) have been attracting much attention due to their excellent antimicrobial efficiency and low rate in driving antimicrobial resistance (AMR) which has been increasing globally to alarming levels. Conjugation of AMPs into functional polymers not only preserves excellent antimicrobial activities but reduces the toxicity and offers more functionalities, which brings new insight towards developing multifunctional biomedical materials such as hydrogels, polymer vesicles, polymer micelles, etc...
March 14, 2018: Biomacromolecules
Noreen J Hickok
No abstract text is available yet for this article.
April 1, 2018: Spine
Raza Aly, Tate Winter, Steve Hall, Tracey Vlahovic
Dermatophytoma is a little-known, difficult to treat fungal infection that complicates onychomycosis. First described by Roberts and Evans in the late 1990's, dermatophytoma presents as a dense concentration of fungal hyphae within or under the nail plate and is generally white or yellow/brown in color, and linear (streaks) or round (patches) in shape; primary etiologic organisms are dermatophytes. Oral antifungals have limited success in treating dermatophytoma owing to difficulties accessing and penetrating what is hypothesized to be a fungal biofilm...
March 1, 2018: Journal of Drugs in Dermatology: JDD
Ripon Sarkar, Aritri Ghosh, Ananya Barui, Pallab Datta
Topical application of honey for tissue regeneration, has recently regained attention in clinical practice with controlled studies affirming its efficacy and indicating its role in regeneration over repair. Parallely, to overcome difficulties of applying raw honey, several product development studies like nanofibrous matrices have been reported. However, one approach concentrated on achieving highest possible honey loading in the nanofiber membranes while other studies have found that only specific honey dilutions result in differential cellular responses on wound healing and re-epithelization...
March 13, 2018: Journal of Materials Science. Materials in Medicine
Roberto Scaffaro, Francesco Lopresti, Manuela D'Arrigo, Andreana Marino, Antonia Nostro
Carvacrol (CAR) is one of the most promising essential oil components with antimicrobial activity. New technologies aimed to incorporate this active molecule into carrier matrix to improve the stability and prolong the biological activity. The goal of this study was to investigate the feasibility of incorporating CAR into electrospun membranes of poly(lactic acid) (PLA) for potential applications as active antimicrobial system. To this end, PLA membranes containing homogeneously dispersed CAR were successfully prepared and a series of systematic tests including morpho-mechanical properties, in vitro release rate, and antimicrobial/antibiofilm activities against Staphylococcus aureus and Candida albicans were carried out...
March 13, 2018: Applied Microbiology and Biotechnology
Md Asaduzzaman Shishir, Md Al Mamun, Md Mahmuduzzaman Mian, Umme Tamanna Ferdous, Noor Jahan Akter, Rajia Sultana Suravi, Suvamoy Datta, Md Ehsanul Kabir
The scarcity of hygienic drinking water is a normal phenomenon in the coastal areas of Bangladesh due to the high salinity of ground water. The inhabitants of this locality, therefore, live on alternative supplies of water including rain-fed pond water, and rainwater with persistent complex microbial interactions therein, often contaminated with life-threatening pathogens. Hence, this study was aimed at analyzing the prevalence of Vibrio cholerae ( Vc ) in the alternative drinking waters of Mathbaria, a coastal subdistrict neighboring the Bay of Bengal, the efficacy of pond sand filter (PSF) and the co-association among Bacillus -like spore formers (Sf) and Vc ...
2018: Frontiers in Public Health
Arwa Abu Khweek, Amal O Amer
Legionella pneumophila ( L. pneumophila ) is an opportunistic waterborne pathogen and the causative agent for Legionnaires' disease, which is transmitted to humans via inhalation of contaminated water droplets. The bacterium is able to colonize a variety of man-made water systems such as cooling towers, spas, and dental lines and is widely distributed in multiple niches, including several species of protozoa In addition to survival in planktonic phase, L. pneumophila is able to survive and persist within multi-species biofilms that cover surfaces within water systems...
2018: Frontiers in Cellular and Infection Microbiology
Lívia Jacovassi Tavares, Marlise Inêz Klein, Beatriz Helena Dias Panariello, Erica Dorigatti de Avila, Ana Cláudia Pavarina
Purpose: The goal of this study was to develop and validate a standardized in vitro pathogenic biofilm attached onto saliva-coated surfaces. Methods: Fusobacterium nucleatum (F. nucleatum) and Porphyromonas gingivalis (P. gingivalis) strains were grown under anaerobic conditions as single species and in dual-species cultures. Initially, the bacterial biomass was evaluated at 24 and 48 hours to determine the optimal timing for the adhesion phase onto saliva-coated polystyrene surfaces...
February 2018: Journal of Periodontal & Implant Science
Ki Bum Ahn, Jung Eun Baik, Cheol-Heui Yun, Seung Hyun Han
A biofilm is an aggregate of microorganisms in which cells adhere to biological or non-biological surfaces and is responsible for various infectious diseases. Infections caused by Staphylococcus aureus , including pneumonia, endocarditis, and osteomyelitis, are often associated with colonization and biofilm formation. Although lipoteichoic acid (LTA) is involved in biofilm formation, the specific role of LTA is not clearly understood. In this study, we demonstrated that LTA released from Lactobacillus plantarum could inhibit S...
2018: Frontiers in Microbiology
Mingming Pu, Lili Sheng, Sooyeon Song, Ting Gong, Thomas K Wood
Pseudomonas aeruginosa causes many biofilm infections, and the rugose small-colony variants (RSCVs) of this bacterium are important for infection. We found here that inactivation of PA2444, which we determined to be a serine hydroxymethyltransferase (SHMT), leads to the RSCV phenotype of P. aeruginosa PA14. In addition, loss of PA2444 increases biofilm formation by two orders of magnitude, increases exopolysaccharide by 45-fold, and abolishes swarming. The RSCV phenotype is related to higher cyclic diguanylate concentrations due to increased activity of the Wsp chemosensory system, including diguanylate cyclase WspR...
2018: Frontiers in Microbiology
S P Rout, L Payne, S Walker, T Scott, P Heard, H Eccles, G Bond, P Shah, P Bills, B R Jackson, S A Boxall, A P Laws, C Charles, S J Williams, P N Humphreys
14 C is an important consideration within safety assessments for proposed geological disposal facilities for radioactive wastes, since it is capable of re-entering the biosphere through the generation of14 C bearing gases. The irradiation of graphite moderators in the UK gas-cooled nuclear power stations has led to the generation of a significant volume of14 C-containing intermediate level wastes. Some of this14 C is present as a carbonaceous deposit on channel wall surfaces. Within this study, the potential of biofilm growth upon irradiated and13 C doped graphite at alkaline pH was investigated...
March 13, 2018: Scientific Reports
Morgan Petrovich, Binh Chu, Dorothy Wright, Jim Griffin, Maryam Elfeki, Brian T Murphy, Rachel Poretsky, George Wells
Wastewater treatment plants (WWTPs) are known to harbor antibiotic resistance genes (ARGs) that are disseminated into the environment via effluent. However, few studies have compared abundance, mobilization, and selective pressures for ARGs in WWTPs as a function of variations in secondary treatment bioprocesses. We used shotgun metagenomics to provide a comprehensive analysis of ARG composition, relationship to mobile genetic elements, and co-occurrences with antibiotic production genes (APGs) throughout two full-scale municipal WWTPs, one of which employs biofilm-based secondary treatment and another that uses a suspended growth system...
March 9, 2018: FEMS Microbiology Ecology
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