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persister cells in biofilm

Lara Thieme, Mareike Klinger-Strobel, Anita Hartung, Claudia Stein, Oliwia Makarewicz, Mathias W Pletz
Background: Enterococci frequently cause severe biofilm-associated infections such as endocarditis. The combination of ampicillin/ceftriaxone has recently been clinically evaluated as non-inferior compared with the standard therapy of ampicillin/gentamicin for treatment of Enterococcus faecalis endocarditis. Ceftaroline is a novel cephalosporin with enhanced activity against Gram-positive bacteria. Objectives: To compare the in vitro effectiveness of the ceftaroline/ampicillin combination with those of gentamicin/ampicillin and ceftriaxone/ampicillin in planktonic and biofilm cultures of clinical E...
February 28, 2018: Journal of Antimicrobial Chemotherapy
Alison Parnham, Chrissie Bousfield
Chronicity in wound healing is a challenge for health services financially and scientifically, with negative consequences on patients' lives. This paper seeks to explore why chronic wounds fail to heal in relation to the inflammatory cellular dysfunction associated with biofilm development. Findings demonstrate an association between chronic wounds failing to heal, the presence of devitalised tissue and abnormal immune cell activity with a consequential excessive release of harmful matrix metalloproteases (MMPs)...
March 2, 2018: British Journal of Community Nursing
Zhaowei Chen, Zhenzhen Wang, Jinsong Ren, Xiaogang Qu
Bacterial infection continues to be a growing global health problem with the most widely accepted treatment paradigms restricted to antibiotics. However, antibiotics overuse and misuse have triggered increased multidrug resistance, frustrating the therapeutic outcomes and leading to higher mortalities. Even worse, the tendency of bacteria to form biofilms on living and nonliving surfaces further increases the difficulty in confronting bacteria because the extracellular matrix can act as a robust barrier to prevent the penetration of antibiotics and resist environmental stress...
February 28, 2018: Accounts of Chemical Research
Mafalda Cavalheiro, Miguel Cacho Teixeira
Candida species are fungal pathogens known for their ability to cause superficial and systemic infections in the human host. These pathogens are able to persist inside the host due to the development of pathogenicity and multidrug resistance traits, often leading to the failure of therapeutic strategies. One specific feature of Candida species pathogenicity is their ability to form biofilms, which protects them from external factors such as host immune system defenses and antifungal drugs. This review focuses on the current threats and challenges when dealing with biofilms formed by Candida albicans, Candida glabrata, Candida tropicalis , and Candida parapsilosis , highlighting the differences between the four species...
2018: Frontiers in Medicine
Robert W McKee, Naira Aleksanyan, Elizabeth M Garrett, Rita Tamayo
Cyclic diguanylate (c-di-GMP) is a second messenger that regulates the transition from motile to sessile lifestyles in numerous bacteria and controls virulence factor production in a variety of pathogens. In Clostridium difficile , c-di-GMP negatively regulates flagellum biosynthesis and swimming motility, and promotes the production of type IV pili (TFP), biofilm formation, and surface motility in vitro Flagella have been identified as colonization factors in C. difficile , but the role of TFP in adherence to host cells and in colonization of the mammalian gut is unknown...
February 26, 2018: Infection and Immunity
Karine Dufresne, Julie Saulnier-Bellemare, France Daigle
The human-specific pathogen Salmonella enterica serovar Typhi causes typhoid, a major public health issue in developing countries. Several aspects of its pathogenesis are still poorly understood. S . Typhi possesses 14 fimbrial gene clusters including 12 chaperone-usher fimbriae ( stg, sth, bcf , fim, saf , sef , sta, stb, stc, std, ste , and tcf ). These fimbriae are weakly expressed in laboratory conditions and only a few are actually characterized. In this study, expression of all S . Typhi chaperone-usher fimbriae and their potential roles in pathogenesis such as interaction with host cells, motility, or biofilm formation were assessed...
2018: Frontiers in Cellular and Infection Microbiology
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
Heidi B Kaplan, Justin A Miranda, Gloria R Gogola, Karen Gomez, Catherine G Ambrose
Polymerase chain reaction (PCR) has been proposed as a method to identify bacteria in clinical samples because it is more sensitive than culture techniques and can produce results rapidly. However, PCR can detect DNA from dead cells and thus cannot distinguish between live and dead cells in a tissue sample. Killed Staphylococcus aureus cells were implanted into the femurs and knee joints of rats to determine the length of time that DNA from dead cells is detectable in a living animal under conditions similar to common orthopedic infections...
February 2, 2018: Diagnostic Microbiology and Infectious Disease
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)...
January 25, 2018: Microbiology
Jun Myoung Yu, Dongping Wang, Leland S Pierson, Elizabeth A Pierson
Pseudomonas chlororaphis 30-84 is a biological control agent selected for its ability to suppress diseases caused by fungal pathogens. P. chlororaphis 30-84 produces three phenazines: phenazine-1-carboxylic acid (PCA), 2-hydroxy-phenazine-1-carboxylic acid (2OHPCA) and a small amount of 2-hydroxy-phenazine (2OHPHZ), and these are required for fungal pathogen inhibition and wheat rhizosphere competence. The two, 2-hydroxy derivatives are produced from PCA via the activity of a phenazine-modifying enzyme encoded by phzO...
February 2018: Plant Pathology Journal
Emelia Hornam Adator, Meining Cheng, Rick Holley, Tim McAllister, Claudia Narvaez-Bravo
Biofilms are known to play important roles in bacterial survival and persistence in food-processing environments. This study aimed to determine the ability of the top 7 STEC serotypes to form biofilms on polystyrene (POL) and stainless steel (SS) plates and to quantify their survival and transfer from dry-surface biofilms to lettuce pieces. The ability of 14 STEC strains to form biofilms on these two materials at different exposure times and temperatures was assessed using crystal violet, Congo red and SEM...
January 25, 2018: International Journal of Food Microbiology
Ching-Yee Loo, Wing-Hin Lee, Gianluca Lauretani, Santo Scalia, David Cipolla, Daniela Traini, Paul Young, Hui Xin Ong
PURPOSE: The failure of chronic therapy with antibiotics to clear persistent respiratory infection is the key morbidity and mortality factor for patients with chronic lung diseases, primarily due to the presence of biofilm in the lungs. It is hypothesised that carbon sources, such as mannitol, could stimulate the metabolic activity of persister cells within biofilms and restore their susceptibility to antibiotics. The aims of the current study are to: (1) establish a representative in vitro model of Pseudomonas aeruginosa biofilm lung infection, and (2) investigate the effects of nebulised mannitol on antibiotic efficacy, focusing on ciprofloxacin, in the eradication of biofilm...
February 7, 2018: Pharmaceutical Research
Gayan Heruka De Zoysa, Hugh Douglas Glossop, Vijayalekshmi Sarojini
Novel antifungal agents are required against pathogenic fungi such as Candida albicans. We report the anticandidal activity of battacin lipopeptide antibiotics with previously unexplored antifungal activity. From amongst sixteen battacin lipopeptides tested against C. alibicans (SC5314) the 4-methyl hexanoyl conjugated trimeric lipopeptide 13 emerged as the lead candidate with a MIC of 6.25 μM and negligible haemolysis of mouse red blood cells. The potency of this lipopeptide was maintained under acidic conditions...
January 9, 2018: European Journal of Medicinal Chemistry
Ee Lin Tek, Joanna F Sundstrom, Jennie M Gardner, Stephen G Oliver, Vladimir Jiranek
Commercially available active dried wine yeasts are regularly used by winemakers worldwide to achieve reliable fermentations and obtain quality wine. This practice has led to increased evidence of traces of commercial wine yeast in the vineyard, winery and uninoculated musts. The mechanism(s) that enables commercial wine yeast to persist in the winery environment and the influence to native microbial communities on this persistence is poorly understood. This study has investigated the ability of commercial wine yeasts to form biofilms and adhere to plastic...
January 31, 2018: FEMS Microbiology Ecology
Damien J Cabral, Jenna I Wurster, Peter Belenky
Persistence is a phenomenon during which a small fraction of a total bacterial population survives treatment with high concentrations of antibiotics for an extended period of time. In conjunction with biofilms, antibiotic persisters represent a major cause of recalcitrant and recurring infections, resulting in significant morbidity and mortality. In this review, we discuss the clinical significance of persister cells and the central role of bacterial metabolism in their formation, specifically with respect to carbon catabolite repression, sugar metabolism, and growth regulation...
February 1, 2018: Pharmaceuticals
Byoung Sik Kim, Song Yee Jang, Ye-Ji Bang, Jungwon Hwang, Youngwon Koo, Kyung Ku Jang, Dongyeol Lim, Myung Hee Kim, Sang Ho Choi
Pathogenic Vibrio species cause diseases in diverse marine animals reared in aquaculture. Since their pathogenesis, persistence, and survival in marine environments are regulated by quorum sensing (QS), QS interference has attracted attention as a means to control these bacteria in aquatic settings. A few QS inhibitors of Vibrio species have been reported, but detailed molecular mechanisms are lacking. Here, we identified a novel, potent, and selective Vibrio QS inhibitor, named QStatin [1-(5-bromothiophene-2-sulfonyl)-1H-pyrazole], which affects Vibrio harveyi LuxR homologues, the well-conserved master transcriptional regulators for QS in Vibrio species...
January 30, 2018: MBio
Sónia Silva, Célia F Rodrigues, Daniela Araújo, Maria Elisa Rodrigues, Mariana Henriques
Candida infections (candidiasis) are the most prevalent opportunistic fungal infection on humans and, as such, a major public health problem. In recent decades, candidiasis has been associated to Candida species other than Candida albicans. Moreover, biofilms have been considered the most prevalent growth form of Candida cells and a strong causative agent of the intensification of antifungal resistance. As yet, no specific resistance factor has been identified as the sole responsible for the increased recalcitrance to antifungal agents exhibited by biofilms...
February 21, 2017: Journal of Fungi (Basel, Switzerland)
Damien Roux, Matthew Schaefers, Bradley S Clark, Molly Weatherholt, Diane Renaud, David Scott, John J LiPuma, Gregory Priebe, Craig Gerard, Deborah R Yoder-Himes
Burkholderia dolosa caused an outbreak in the cystic fibrosis clinic at Boston Children's Hospital and was associated with high mortality in these patients. This species is part of a larger complex of opportunistic pathogens known as the Burkholderia cepacia complex (Bcc). Compared to other species in the Bcc, B. dolosa is highly transmissible; thus understanding its virulence mechanisms is important for preventing future outbreaks. The genome of one of the outbreak strains, AU0158, revealed a homolog of the lafA gene encoding a putative lateral flagellin, which, in other non-Bcc species, is used for movement on solid surfaces, attachment to host cells, or movement inside host cells...
2018: PloS One
Tarsila M Camargo, Rafael N Stipp, Lívia A Alves, Erika N Harth-Chu, José F Höfling, Renata O Mattos-Graner
Streptococcus sanguinis is a pioneer species of teeth and a common opportunistic pathogen of infective endocarditis. In this study, we identified a two-component system, SptRS Ss , affecting S. sanguinis survival in saliva and biofilm formation. Isogenic mutants of sptRSs (SKsptR) and sptSSs (SKsptS) showed reduced cell counts in ex vivo assays of viability in saliva, compared to parent strain SK36 and complemented mutants. Reduced counts of the mutants in saliva were associated with reduced growth rates in poor nutrient medium (RPMI) and increased susceptibility to deposition of C3b and MAC of the complement system, a defense component of saliva and serum...
January 16, 2018: Infection and Immunity
Umender Sharma, Aradhana Vipra, Shankaramurthy Channabasappa
Bacterial biofilms are highly resistant to the action of antibiotics. Presence of persisters, phenotypically resistant populations of bacterial cells, is thought to contribute toward recalcitrance of biofilms. The phage-derived lysins, by virtue of their ability to cleave the peptidoglycan of bacterial cells in an enzymatic manner, have the unique ability to kill dormant cells. Several lysins have shown potent antibiofilm activity in vitro. The fact that lysins have shown better efficacy than conventional drugs in animal models of endocarditis and other infections involving biofilms suggests that the lysins can potentially be developed against difficult-to-treat bacterial infections...
January 8, 2018: Drug Discovery Today
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