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Bacterial persistence

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https://www.readbyqxmd.com/read/28431569/co-colonisation-with-aspergillus-fumigatus-and-pseudomonas-aeruginosa-is-associated-with-poorer-health-in-cystic-fibrosis-patients-an-irish-registry-analysis
#1
Emma Reece, Ricardo Segurado, Abaigeal Jackson, Siobhán McClean, Julie Renwick, Peter Greally
BACKGROUND: Pulmonary infection is the main cause of death in cystic fibrosis (CF). Aspergillus fumigatus (AF) and Pseudomonas aeruginosa (PA) are the most prevalent fungal and bacterial pathogens isolated from the CF airway, respectively. Our aim was to determine the effect of different colonisation profiles of AF and PA on the clinical status of patients with CF. METHODS: A retrospective analysis of data from the Cystic Fibrosis Registry of Ireland from 2013 was performed to determine the effect of intermittent and persistent colonisation with AF or PA or co-colonisation with both microorganisms on clinical outcome measures in patients with CF...
April 21, 2017: BMC Pulmonary Medicine
https://www.readbyqxmd.com/read/28431088/stationary-phase-genes-upregulated-by-polyamines-are-responsible-for-the-formation-of-escherichia-coli-persister-cells-tolerant-to-netilmicin
#2
Alexander G Tkachenko, Natalya M Kashevarova, Elena A Tyuleneva, Mikhail S Shumkov
Persisters are rare phenotypic variants of regular bacterial cells that survive lethal antibiotics or stresses owing to slowing down of their metabolism. Recently, we have shown that polyamine putrescine can upregulate persister cell formation in Escherichia coli via the stimulation of rpoS expression, encoding a master regulator of general stress response. We hypothesized that rmf and yqjD, the stationary-phase genes responsible for ribosome inactivation, might be good candidates for the similar role owing to their involvement in translational arrest and the ability to be affected by polyamines...
April 19, 2017: FEMS Microbiology Letters
https://www.readbyqxmd.com/read/28430938/characterization-of-yjjj-toxin-of-escherichia-coli
#3
Yuki Maeda, Chun-Yi Lin, Yojiro Ishida, Masayori Inouye, Yoshihiro Yamaguchi, Sangita Phadtare
Reminiscent of eukaryotic apoptotic programmed cell death, bacteria also contain a large number of suicide genes, which are in general co-expressed with their cognate antitoxic genes. These systems called the toxin-antitoxin (TA) systems are associated with cellular dormancy, and play major roles in biofilm formation and persistent multi-drug resistance of many human pathogens. In recent years, the study on TA system toxins has become a hot topic due to the health implications of these toxins by virtue of their role in bacterial pathogenicity...
April 19, 2017: FEMS Microbiology Letters
https://www.readbyqxmd.com/read/28427896/toll-like-receptor-2-an-important-immunomodulatory-molecule-during-helicobacter-pylori-infection
#4
REVIEW
Maryam Nemati, Tiziana Larussa, Hossein Khorramdelazad, Merat Mahmoodi, Abdollah Jafarzadeh
Toll like receptors (TLRs) are an essential subset of pathogen recognition receptors (PRRs) which identify the microbial components and contribute in the regulation of innate and adaptive immune responses against the infectious agents. The TLRs, especially TLR2, TLR4, TLR5 and TLR9, participate in the induction of immune response against H. pylori. TLR2 is expressed on a number of immune and non-immune cells and recognizes a vast broad of microbial components due to its potential to form heterodimers with other TLRs, including TLR1, TLR6 and TLR10...
April 17, 2017: Life Sciences
https://www.readbyqxmd.com/read/28422754/mpeg1-perforin-2-mutations-in-human-pulmonary-nontuberculous-mycobacterial-infections
#5
Ryan M McCormack, Eva P Szymanski, Amy P Hsu, Elena Perez, Kenneth N Olivier, Eva Fisher, E Brook Goodhew, Eckhard R Podack, Steven M Holland
Perforin-2 is a highly conserved pore-forming protein encoded by macrophage expressed gene 1 (MPEG1). A number of studies have shown that Perforin-2-deficient mice are unable to survive following a bacterial challenge that is nonlethal in WT mice. There is also recent evidence that Mpeg1+/- heterozygous mice display an intermediate killing ability compared with Mpeg1 WT and Mpeg1-/- mice. Despite these in vivo findings, to date, no perforin-2 deficiencies have been associated with human disease. Here, we report four patients with persistent nontuberculous mycobacterial infection who had heterozygous MPEG1 mutations...
April 20, 2017: JCI Insight
https://www.readbyqxmd.com/read/28422568/cgas-sting-tbk1-irf3-7-induced-interferon-%C3%AE-contributes-to-the-clearing-of-non-tuberculous-mycobacterial-infection-in-mice
#6
Nanthapon Ruangkiattikul, Andreas Nerlich, Ketema Abdissa, Stefan Lienenklaus, Abdulhadi Suwandi, Nina Janze, Kristin Laarmann, Julia Spanier, Ulrich Kalinke, Siegfried Weiss, Ralph Goethe
Type I interferons (IFN-I), such as IFN-α and IFN-β are important messengers in the host response against bacterial infections. Knowledge about the role of IFN-I in infections by nontuberculous mycobacteria (NTM) is limited. Here we show that macrophages infected with pathogens of the Mycobacterium avium complex produced significantly lower amounts of IFN-β than macrophages infected with the opportunistic pathogen M. smegmatis. To dissect the molecular mechanisms of this phenomenon, we focussed on the obligate pathogen Mycobacterium avium ssp...
April 19, 2017: Virulence
https://www.readbyqxmd.com/read/28422188/resolvin-d1-enhances-the-resolution-of-lung-inflammation-caused-by-long-term-pseudomonas-aeruginosa-infection
#7
M Codagnone, E Cianci, A Lamolinara, V C Mari, A Nespoli, E Isopi, D Mattoscio, M Arita, A Bragonzi, M Iezzi, M Romano, A Recchiuti
Pseudomonas aeruginosa lung infection is a main cause of disability and mortality worldwide. Acute inflammation and its timely resolution are crucial for ensuring bacterial clearance and limiting tissue damage. Here, we investigated protective actions of resolvin (Rv) D1 in lung infection induced by the RP73 clinical strain of P. aeruginosa. RvD1 significantly diminished bacterial growth and neutrophil infiltration during acute pneumonia caused by RP73. Inoculum of RP73, immobilized in agar beads, resulted in persistent lung infection up to 21 days, leading to a non resolving inflammation reminiscent of human pathology...
April 19, 2017: Mucosal Immunology
https://www.readbyqxmd.com/read/28421881/factors-pivotal-for-designing-of-nanoantimicrobials-an-exposition
#8
Bushra Jamil, Muhammad Imran
Understanding the interplay between bacterial pathogens and antimicrobials is a key to realize the control over infections causing morbidity and mortality. An important current issue of contemporary medicine and microbiology is the search for new strategies for adequate therapy of infectious diseases associated with rapidly emerging multidrug-resistant (MDR) pathogens. Recently, a great deal of progress has been made in the field of nanobiotechnology towards the development of various nanoantimicrobials (NAMs) as novel therapeutic solution...
April 19, 2017: Critical Reviews in Microbiology
https://www.readbyqxmd.com/read/28421166/in-vivo-and-in-vitro-interactions-between-pseudomonas-aeruginosa-and-staphylococcus-spp
#9
REVIEW
An Hotterbeekx, Samir Kumar-Singh, Herman Goossens, Surbhi Malhotra-Kumar
The significance of polymicrobial infections is increasingly being recognized especially in a biofilm context wherein multiple bacterial species-including both potential pathogens and members of the commensal flora-communicate, cooperate, and compete with each other. Two important bacterial pathogens that have developed a complex network of evasion, counter-inhibition, and subjugation in their battle for space and nutrients are Pseudomonas aeruginosa and Staphylococcus aureus. Their strain- and environment-specific interactions, for instance in the cystic fibrosis lung or in wound infections, show severe competition that is generally linked to worse patient outcomes...
2017: Frontiers in Cellular and Infection Microbiology
https://www.readbyqxmd.com/read/28420398/mechanisms-of-corticosteroid-insensitivity-in-copd-alveolar-macrophages-exposed-to-nthi
#10
Rana M Khalaf, Simon R Lea, Hannah J Metcalfe, Dave Singh
BACKGROUND: Non-typeable Haemophilus influenza (NTHi) infection is common in COPD. Corticosteroids can have limited therapeutic effects in COPD patients. NTHi causes corticosteroid insensitive cytokine production from COPD alveolar macrophages. We investigated the mechanisms by which NTHi causes corticosteroid insensitive inflammatory responses, and the effects of NTHi exposure on COPD macrophage polarisation. METHOD: Alveolar macrophages from COPD patients and controls were exposed to NTHi in conjunction with the corticosteroid dexamethasone and/or the p38 MAPK inhibitor BIRB-796...
April 18, 2017: Respiratory Research
https://www.readbyqxmd.com/read/28419279/primates-lice-and-bacteria-speciation-and-genome-evolution-in-the-symbionts-of-hominid-lice
#11
Bret M Boyd, Julie M Allen, Nam-Phuong Nguyen, Pranjal Vachaspati, Zach Quicksall, Tandy Warnow, Lawrence Mugisha, Kevin P Johnson, David L Reed
Insects with restricted diets rely on symbiotic bacteria to provide essential metabolites missing in their diet. The blood-sucking lice are obligate, host-specific parasites of mammals and are themselves host to symbiotic bacteria. In human lice, these bacterial symbionts supply the lice with B-vitamins. Here we sequenced the genomes of symbiotic and heritable bacterial of human, chimpanzee, gorilla, and monkey lice and used phylogenomics to investigate their evolutionary relationships. We find that these symbionts have a phylogenetic history reflecting the louse phylogeny, a finding contrary to previous reports of symbiont replacement...
April 14, 2017: Molecular Biology and Evolution
https://www.readbyqxmd.com/read/28412935/fitness-costs-of-symbiont-switching-using-entomopathogenic-nematodes-as-a-model
#12
John G McMullen, Brittany F Peterson, Steven Forst, Heidi Goodrich Blair, S Patricia Stock
BACKGROUND: Steinernematid nematodes form obligate symbioses with bacteria from the genus Xenorhabdus. Together Steinernema nematodes and their bacterial symbionts successfully infect, kill, utilize, and exit their insect hosts. During this process the nematodes and bacteria disassociate requiring them to re-associate before emerging from the host. This interaction can be complicated when two different nematodes co-infect an insect host. RESULTS: Non-cognate nematode-bacteria pairings result in reductions for multiple measures of success, including total progeny production and virulence...
April 17, 2017: BMC Evolutionary Biology
https://www.readbyqxmd.com/read/28411218/the-conjugative-relaxase-trwc-promotes-integration-of-foreign-dna-in-the-human-genome
#13
Coral González-Prieto, Richard Gabriel, Christoph Dehio, Manfred Schmidt, Matxalen Llosa
Bacterial conjugation is a mechanism of horizontal DNA transfer. The relaxase TrwC of the conjugative plasmid R388 cleaves one strand of the transferred DNA at the oriT, covalently attaches to it and leads the ssDNA into the recipient cell. In addition, TrwC catalyzes site-specific integration of the transferred DNA into its target sequence present in the genome of the recipient bacterium. Here, we report the analysis of the efficiency and specificity of the integrase activity of TrwC in human cells, using the Type IV Secretion System of the human pathogen Bartonella henselae to introduce relaxase-DNA complexes...
April 14, 2017: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/28411217/transfer-potential-of-plasmids-encoding-extended-spectrum-cephalosporin-resistance-in-escherichia-coli-from-poultry
#14
Solveig Sølverød Mo, Marianne Sunde, Hanna Karin Ilag, Solveig Langsrud, Even Heir
Escherichia coli resistant to extended-spectrum cephalosporins (ESC) are widely distributed in Norwegian broiler production, and the majority harbour transferable IncK or IncI1 plasmids with blaCMY-2 Persistent occurrence in broiler farms may occur through survival of ESC-resistant E. coli in the farm environment, or by transfer and maintenance of resistance plasmids within a population of environmental bacteria with high survival abilities. The aim of this study was to determine the transferability of two successful blaCMY-2 carrying plasmids belonging to the incompatibility groups IncK and IncI1, into E...
April 14, 2017: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/28410379/new-insights-into-valve-related-intramural-and-intracellular-bacterial-diversity-in-infective-endocarditis
#15
Andreas Oberbach, Nadine Schlichting, Stefan Feder, Stefanie Lehmann, Yvonne Kullnick, Tilo Buschmann, Conny Blumert, Friedemann Horn, Jochen Neuhaus, Ralph Neujahr, Erik Bagaev, Christian Hagl, Maximilian Pichlmaier, Arne Christian Rodloff, Sandra Gräber, Katharina Kirsch, Marcus Sandri, Vivek Kumbhari, Armirhossein Behzadi, Amirali Behzadi, Joao Carlos Correia, Friedrich Wilhelm Mohr, Maik Friedrich
AIMS: In infective endocarditis (IE), a severe inflammatory disease of the endocardium with an unchanged incidence and mortality rate over the past decades, only 1% of the cases have been described as polymicrobial infections based on microbiological approaches. The aim of this study was to identify potential biodiversity of bacterial species from infected native and prosthetic valves. Furthermore, we compared the ultrastructural micro-environments to detect the localization and distribution patterns of pathogens in IE...
2017: PloS One
https://www.readbyqxmd.com/read/28407752/detection-of-high-serum-levels-of-%C3%AE-d-glucan-in-disseminated-nocardial-infection-a-case-report
#16
Toyomitsu Sawai, Takumi Nakao, Shota Yamaguchi, Sumako Yoshioka, Nobuko Matsuo, Naofumi Suyama, Katsunori Yanagihara, Hiroshi Mukae
BACKGROUND: β-D-glucan (BDG) is a helpful diagnostic marker for many invasive fungal infections, but not for nocardiosis. Here, we reported the first case of nocardial infection with high serum level of BDG. CASE PRESENTATION: A 73-year-old man was hospitalized because of fever, headache, and appetite loss after 10 months of steroid and immunosuppressive therapy for cryptogenic organizing pneumonia. With a diagnosis of bacterial pneumonia, treatment with ampicillin/sulbactam was initiated...
April 13, 2017: BMC Infectious Diseases
https://www.readbyqxmd.com/read/28407427/microenvironmental-characteristics-and-physiology-of-biofilms-in-chronic-infections-of-cf-patients-are-strongly-affected-by-the-host-immune-response
#17
REVIEW
Peter Ø Jensen, Mette Kolpen, Kasper N Kragh, Michael Kühl
In vitro studies of Pseudomonas aeruginosa and other pathogenic bacteria in biofilm aggregates have yielded detailed insight into their potential growth modes and metabolic flexibility under exposure to gradients of substrate and electron acceptor. However, the growth pattern of P. aeruginosa in chronic lung infections of cystic fibrosis (CF) patients is very different from what is observed in vitro, for example, in biofilms grown in flow chambers. Dense in vitro biofilms of P. aeruginosa exhibit rapid O2 depletion within <50-100 μm due to their own aerobic metabolism...
April 2017: APMIS: Acta Pathologica, Microbiologica, et Immunologica Scandinavica
https://www.readbyqxmd.com/read/28407421/central-venous-catheters-and-biofilms-where-do-we-stand-in-2017
#18
REVIEW
Marie Gominet, Fabrice Compain, Christophe Beloin, David Lebeaux
The use of central venous catheters (CVC) is associated with a risk of microbial colonization and subsequent potentially severe infection. Microbial contamination of the catheter leads to the development of a microbial consortia associated with the CVC surface and embedded in an extracellular matrix, named biofilm. This biofilm provides bacterial cells the ability to survive antimicrobial agents and the host immune system and to disseminate to other sites of the body. The best preventive strategy is to avoid any unnecessary catheterization or to reduce indwelling duration when a CVC is required...
April 2017: APMIS: Acta Pathologica, Microbiologica, et Immunologica Scandinavica
https://www.readbyqxmd.com/read/28407419/antibiotic-treatment-of-biofilm-infections
#19
REVIEW
Oana Ciofu, Estrella Rojo-Molinero, María D Macià, Antonio Oliver
Bacterial biofilms are associated with a wide range of infections, from those related to exogenous devices, such as catheters or prosthetic joints, to chronic tissue infections such as those occurring in the lungs of cystic fibrosis patients. Biofilms are recalcitrant to antibiotic treatment due to multiple tolerance mechanisms (phenotypic resistance). This causes persistence of biofilm infections in spite of antibiotic exposure which predisposes to antibiotic resistance development (genetic resistance). Understanding the interplay between phenotypic and genetic resistance mechanisms acting on biofilms, as well as appreciating the diversity of environmental conditions of biofilm infections which influence the effect of antibiotics are required in order to optimize the antibiotic treatment of biofilm infections...
April 2017: APMIS: Acta Pathologica, Microbiologica, et Immunologica Scandinavica
https://www.readbyqxmd.com/read/28402891/brownian-ratchet-mechanism-for-faithful-segregation-of-low-copy-number-plasmids
#20
Longhua Hu, Anthony G Vecchiarelli, Kiyoshi Mizuuchi, Keir C Neuman, Jian Liu
Bacterial plasmids are extrachromosomal DNA that provides selective advantages for bacterial survival. Plasmid partitioning can be remarkably robust. For high-copy-number plasmids, diffusion ensures that both daughter cells inherit plasmids after cell division. In contrast, most low-copy-number plasmids need to be actively partitioned by a conserved tripartite ParA-type system. ParA is an ATPase that binds to chromosomal DNA; ParB is the stimulator of the ParA ATPase and specifically binds to the plasmid at a centromere-like site, parS...
April 11, 2017: Biophysical Journal
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