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https://www.readbyqxmd.com/read/29769360/multiple-large-inversions-and-breakpoint-rewiring-of-gene-expression-in-the-evolution-of-the-fire-ant-social-supergene
#1
Yu-Ching Huang, Viet Dai Dang, Ni-Chen Chang, John Wang
Supergenes consist of co-adapted loci that segregate together and are associated with adaptive traits. In the fire ant Solenopsis invicta , two 'social' supergene variants regulate differences in colony queen number and other traits. Suppressed recombination in this system is maintained, in part, by a greater than 9 Mb inversion, but the supergene is larger. Has the supergene in S. invicta undergone multiple large inversions? The initial gene content of the inverted allele of a supergene would be the same as that of the wild-type allele...
May 16, 2018: Proceedings. Biological Sciences
https://www.readbyqxmd.com/read/29740409/enhanced-fluorescent-siderophore-biosynthesis-and-loss-of-phenazine-1-carboxamide-in-phenotypic-variant-of-pseudomonas-chlororaphis-ht66
#2
Yang Liu, Zheng Wang, Muhammad Bilal, Hongbo Hu, Wei Wang, Xianqing Huang, Huasong Peng, Xuehong Zhang
Pseudomonas chlororaphis HT66 is a plant-beneficial bacterium that exhibits wider antagonistic spectrum against a variety of plant pathogenic fungi due to its main secondary metabolite, i.e., phenazine-1-carboxamide (PCN). In the present study, a spontaneous phenotypic variant designated as HT66-FLUO was isolated from the fermentation process of wild-type HT66 strain. The newly isolated phenotypic variant was morphologically distinct from the wild-type strain such as larger cell size, semi-transparent, non-production of PCN (Green or yellow crystals) and enhanced fluorescence under UV light...
2018: Frontiers in Microbiology
https://www.readbyqxmd.com/read/29691335/novel-insights-into-staphylococcus-aureus-deep-bone-infections-the-involvement-of-osteocytes
#3
Dongqing Yang, Asiri R Wijenayaka, Lucian B Solomon, Stephen M Pederson, David M Findlay, Stephen P Kidd, Gerald J Atkins
Periprosthetic joint infection (PJI) is a potentially devastating complication of orthopedic joint replacement surgery. PJI with associated osteomyelitis is particularly problematic and difficult to cure. Whether viable osteocytes, the predominant cell type in mineralized bone tissue, have a role in these infections is not clear, although their involvement might contribute to the difficulty in detecting and clearing PJI. Here, using Staphylococcus aureus , the most common pathogen in PJI, we demonstrate intracellular infection of human-osteocyte-like cells in vitro and S...
April 24, 2018: MBio
https://www.readbyqxmd.com/read/29610201/tomatidine-a-lead-antibiotic-molecule-that-targets-staphylococcus-aureus-atp-synthase-subunit-c
#4
Maxime Lamontagne Boulet, Charles Isabelle, Isabelle Guay, Eric Brouillette, Jean-Philippe Langlois, Pierre-Étienne Jacques, Sébastien Rodrigue, Ryszard Brzezinski, Pascale B Beauregard, Kamal Bouarab, Kumaraswamy Boyapelly, Pierre-Luc Boudreault, Éric Marsault, François Malouin
Methicillin-resistant Staphylococcus aureus (MRSA) is a leading cause of deadly hospital-acquired infections. The discovery of anti- Staphylococcus antibiotics and new classes of drugs not susceptible to the mechanisms of resistance shared among bacteria is imperative. We recently showed that tomatidine (TO), a steroidal alkaloid from solanaceous plants, possesses potent antibacterial activity against S. aureus small colony variants (SCVs), the notoriously persistent form of this bacterium that has been associated with recurrence of infections...
April 2, 2018: Antimicrobial Agents and Chemotherapy
https://www.readbyqxmd.com/read/29594069/-tetrahymena-thermophila-predation-enhances-environmental-adaptation-of-the-carp-pathogenic-strain-aeromonas-hydrophila-nj-35
#5
Jin Liu, Yuhao Dong, Nannan Wang, Shougang Li, Yuanyuan Yang, Yao Wang, Furqan Awan, Chengping Lu, Yongjie Liu
Persistence of Aeromonas hydrophila in aquatic environments is the principle cause of fish hemorrhagic septicemia. Protistan predation has been considered to be a strong driving force for the evolution of bacterial defense strategies. In this study, we investigated the adaptive traits of A. hydrophila NJ-35, a carp pathogenic strain, in response to Tetrahymena thermophila predation. After subculturing with Tetrahymena , over 70% of A. hydrophila colonies were small colony variants (SCVs). The SCVs displayed enhanced biofilm formation, adhesion, fitness, and resistance to bacteriophage infection and oxidative stress as compared to the non- Tetrahymena- exposed strains...
2018: Frontiers in Cellular and Infection Microbiology
https://www.readbyqxmd.com/read/29594066/a-simple-and-rapid-gene-disruption-strategy-in-mycobacterium-abscessus-on-the-design-and-application-of-glycopeptidolipid-mutants
#6
Albertus Viljoen, Ana Victoria Gutiérrez, Christian Dupont, Eric Ghigo, Laurent Kremer
Little is known about the disease-causing genetic determinants that are used by Mycobacterium abscessus , increasingly acknowledged as an important emerging pathogen, notably in cystic fibrosis. The presence or absence of surface exposed glycopeptidolipids (GPL) conditions the smooth (S) or rough (R) M. abscessus subsp. abscessus ( M. abscessus ) variants, respectively, which are characterized by distinct infective programs. However, only a handful of successful gene knock-out and conditional mutants have been reported in M...
2018: Frontiers in Cellular and Infection Microbiology
https://www.readbyqxmd.com/read/29535691/serine-hydroxymethyltransferase-shra-pa2444-controls-rugose-small-colony-variant-formation-in-pseudomonas-aeruginosa
#7
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
https://www.readbyqxmd.com/read/29507890/antibiotic-stimulation-of-a-bacillus-subtilis-migratory-response
#8
Yongjin Liu, Steven Kyle, Paul D Straight
Competitive interactions between bacteria reveal physiological adaptations that benefit fitness. Bacillus subtilis is a Gram-positive species with several adaptive mechanisms for competition and environmental stress. Biofilm formation, sporulation, and motility are the outcomes of widespread changes in a population of B. subtilis . These changes emerge from complex, regulated pathways for adapting to external stresses, including competition from other species. To identify competition-specific functions, we cultured B...
January 2018: MSphere
https://www.readbyqxmd.com/read/29506271/in-vitro-synergism-and-anti-biofilm-activity-of-ampicillin-gentamicin-ceftaroline-and-ceftriaxone-against-enterococcus-faecalis
#9
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
https://www.readbyqxmd.com/read/29501453/staphylococcus-aureus-in-the-airways-of-cystic-fibrosis-patients-a-retrospective-long-term-study
#10
Mathias Schwerdt, Claudia Neumann, Bianca Schwartbeck, Stefanie Kampmeier, Susann Herzog, Dennis Görlich, Angelika Dübbers, Jörg Große-Onnebrink, Christina Kessler, Peter Küster, Holger Schültingkemper, Janina Treffon, Georg Peters, Barbara C Kahl
BACKGROUND: Cystic fibrosis (CF) is an autosomal recessive disease associated with chronic airway infections by Staphylococcus aureus as one of the earliest and most prevalent pathogens. We conducted a retrospective study to determine the S. aureus infection status of CF patients treated since 1994 at two certified CF-centres in Münster, Germany, to get insights into the dynamics of S. aureus airway infection and the clinical impact on lung function on a long-term perspective. MATERIALS AND METHODS: We used data from our microbiological database collected between 1994 and 2016 for patients treated at two centres in Münster, Germany, respectively, to determine the infection status for S...
February 24, 2018: International Journal of Medical Microbiology: IJMM
https://www.readbyqxmd.com/read/29497096/fatty-acid-supplementation-reverses-the-small-colony-variant-phenotype-in-triclosan-adapted-staphylococcus-aureus-genetic-proteomic-and-phenotypic-analyses
#11
Abdulrahman S Bazaid, Sarah Forbes, Gavin J Humphreys, Ruth G Ledder, Ronan O'Cualain, Andrew J McBain
Staphylococcus aureus can develop a small colony variant (SCV) phenotype in response to sub-lethal exposure to the biocide triclosan. In the current study, whole genome sequencing was performed and changes in virulence were investigated in five Staphylococcus aureus strains following repeated exposure to triclosan. Following exposure, 4/5 formed SCV and exhibited point mutations in the triclosan target gene fabI with 2/4 SCVs showing mutations in both fabI and fabD. The SCV phenotype was in all cases immediately reversed by nutritional supplementation with fatty acids or by repeated growth in the absence of triclosan, although fabI mutations persisted in 3/4 reverted SCVs...
March 1, 2018: Scientific Reports
https://www.readbyqxmd.com/read/29439722/tomatidine-and-analog-fc04-100-possess-bactericidal-activities-against-listeria-bacillus-and-staphylococcus-spp
#12
Isabelle Guay, Simon Boulanger, Charles Isabelle, Eric Brouillette, Félix Chagnon, Kamal Bouarab, Eric Marsault, François Malouin
BACKGROUND: Tomatidine (TO) is a plant steroidal alkaloid that possesses an antibacterial activity against the small colony variants (SCVs) of Staphylococcus aureus. We report here the spectrum of activity of TO against other species of the Bacillales and the improved antibacterial activity of a chemically-modified TO derivative (FC04-100) against Listeria monocytogenes and antibiotic multi-resistant S. aureus (MRSA), two notoriously difficult-to-kill microorganisms. METHODS: Bacillus and Listeria SCVs were isolated using a gentamicin selection pressure...
February 13, 2018: BMC Pharmacology & Toxicology
https://www.readbyqxmd.com/read/29416528/substrate-binding-protein-dppa1-of-abc-transporter-dppbcdf-increases-biofilm-formation-in-pseudomonas-aeruginosa-by-inhibiting-pf5-prophage-lysis
#13
Yunho Lee, Sooyeon Song, Lili Sheng, Lei Zhu, Jun-Seob Kim, Thomas K Wood
Filamentous phage impact biofilm development, stress tolerance, virulence, biofilm dispersal, and colony variants. Previously, we identified 137 Pseudomonas aeruginosa PA14 mutants with more than threefold enhanced and 88 mutants with more than 10-fold reduced biofilm formation by screening 5850 transposon mutants ( PLoS Pathogens 5 : e1000483, 2009). Here, we characterized the function of one of these 225 mutations, dppA1 (PA14_58350), in regard to biofilm formation. DppA1 is a substrate-binding protein (SBP) involved in peptide utilization via the DppBCDF ABC transporter system...
2018: Frontiers in Microbiology
https://www.readbyqxmd.com/read/29404415/convergent-evolution-driven-by-rifampin-exacerbates-the-global-burden-of-drug-resistant-staphylococcus-aureus
#14
Romain Guérillot, Anders Gonçalves da Silva, Ian Monk, Stefano Giulieri, Takehiro Tomita, Eloise Alison, Jessica Porter, Sacha Pidot, Wei Gao, Anton Y Peleg, Torsten Seemann, Timothy P Stinear, Benjamin P Howden
Mutations in the beta-subunit of bacterial RNA polymerase (RpoB) cause resistance to rifampin (Rifr ), a critical antibiotic for treatment of multidrug-resistant Staphylococcus aureus . In vitro studies have shown that RpoB mutations confer decreased susceptibility to other antibiotics, but the clinical relevance is unknown. Here, by analyzing 7,099 S. aureus genomes, we demonstrate that the most prevalent RpoB mutations promote clinically relevant phenotypic plasticity resulting in the emergence of stable S...
January 2018: MSphere
https://www.readbyqxmd.com/read/29394295/pseudomonas-aeruginosa-rugose-small-colony-variants-evade-host-clearance-are-hyper-inflammatory-and-persist-in-multiple-host-environments
#15
Matthew J Pestrak, Sarah B Chaney, Heather C Eggleston, Sheri Dellos-Nolan, Sriteja Dixit, Shomita S Mathew-Steiner, Sashwati Roy, Matthew R Parsek, Chandan K Sen, Daniel J Wozniak
Pseudomonas aeruginosa causes devastating infections in immunocompromised individuals. Once established, P. aeruginosa infections become incredibly difficult to treat due to the development of antibiotic tolerant, aggregated communities known as biofilms. A hyper-biofilm forming clinical variant of P. aeruginosa, known as a rugose small-colony variant (RSCV), is frequently isolated from chronic infections and is correlated with poor clinical outcome. The development of these mutants during infection suggests a selective advantage for this phenotype, but it remains unclear how this phenotype promotes persistence...
February 2018: PLoS Pathogens
https://www.readbyqxmd.com/read/29378720/-in-vitro-susceptibility-of-clinical-staphylococcus-aureus-small-colony-variants-to-%C3%AE-lactam-and-non-%C3%AE-lactam-antibiotics
#16
Evgeny A Idelevich, André Kriegeskorte, Nina Schleimer, Georg Peters, Christof von Eiff, Karsten Becker
The Staphylococcus aureus small-colony variant (SCV) phenotype has been associated with relapsing and antibiotic-refractory infections. However, little is known about the activities of antibiotics on clinical SCVs. Here, we demonstrated that SCVs without detectable auxotrophies were at least as susceptible to most β-lactam and non-β-lactam antibiotics in vitro as their corresponding clonally identical strains with a normal phenotype. After prolonged incubation, a regrowth phenomenon has been observed in gradient diffusion inhibition zones irrespective of the strains' phenotype...
April 2018: Antimicrobial Agents and Chemotherapy
https://www.readbyqxmd.com/read/29378202/de-novo-assembly-of-honey-bee-rna-viral-genomes-by-tapping-into-the-innate-insect-antiviral-response-pathway
#17
Elisabeth Fung, Kelly Hill, Katja Hogendoorn, Richard V Glatz, Kathryn R Napier, Matthew I Bellgard, Roberto A Barrero
Bee pollination is critical for improving productivity of one third of all plants or plant products consumed by humans. The health of honey bees is in decline in many countries worldwide, and RNA viruses together with other biological, environmental and anthropogenic factors have been identified as the main causes. The rapid genetic variation of viruses represents a challenge for diagnosis. Thus, application of deep sequencing methods for detection and analysis of viruses has increased over the last years. In this study, we leverage from the innate Dicer-2 mediated antiviral response against viruses to reconstruct complete viral genomes using virus-derived small interfering RNAs (vsiRNAs)...
February 2018: Journal of Invertebrate Pathology
https://www.readbyqxmd.com/read/29343421/frequency-of-small-colony-variants-and-antimicrobial-susceptibility-of-methicillin-resistant-staphylococcus-aureus-in-cystic-fibrosis-patients
#18
Nuntra Suwantarat, Mayer Rubin, Latetia Bryan, Tsigereda Tekle, Michael P Boyle, Karen C Carroll, Mark T Jennings
BACKGROUND: Small-colony variants (SCVs) are a distinct phenotype of Staphylococcus aureus, known for their role in chronic, difficult to treat infections, including cystic fibrosis (CF) lung disease. The goal of this study was to characterize SCV MRSA infection in an adult and pediatric CF population and to identify antibiotic susceptibility patterns unique to SCV MRSA. METHODS: We recovered methicillin-resistant S. aureus (MRSA) from respiratory culture samples from CF patients at the Johns Hopkins Hospital during a 6month study period...
December 2, 2017: Diagnostic Microbiology and Infectious Disease
https://www.readbyqxmd.com/read/29336620/the-role-of-the-pi3k-mtor-signaling-pathway-in-staphylococcus-epidermidis-small-colony-variants-intracellular-survival
#19
Agnieszka Magryś, Agnieszka Bogut, Michał Kiełbus, Alina Olender
The objective of this study was to analyze how Staphylococcus epidermidis SCV and WT strains manipulate the PI3K/Akt/mTOR signaling pathway. Six S. epidermidis strains with normal phenotype (WT) and six S. epidermidis strains with SCV phenotype were isolated in parallel from six patients with the prosthetic hip joint infections. THP-1 activated cells were incubated with or without PI3K inhibitor-wortmannin or with mTOR inhibitor-rapamycin. Next, macrophages were exposed to S. epidermidis WT and SCV strains...
April 2018: Immunological Investigations
https://www.readbyqxmd.com/read/29250041/-stenotrophomonas-maltophilia-as-an-emerging-ubiquitous-pathogen-looking-beyond-contemporary-antibiotic-therapy
#20
REVIEW
Anthony A Adegoke, Thor A Stenström, Anthony I Okoh
Stenotrophomonas maltophilia is a commensal and an emerging pathogen earlier noted in broad-spectrum life threatening infections among the vulnerable, but more recently as a pathogen in immunocompetent individuals. The bacteria are consistently being implicated in necrotizing otitis, cutaneous infections including soft tissue infection and keratitis, endocarditis, meningitis, acute respiratory tract infection (RTI), bacteraemia (with/without hematological malignancies), tropical pyomyositis, cystic fibrosis, septic arthritis, among others...
2017: Frontiers in Microbiology
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