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In vitro antimicrobial activity of royleanone derivatives against Gram positive bacterial pathogens

Rijo, P.; Duarte, A.; Francisco, A. P.; Semedo-Lemsaddek, T.; Simões, M. F.
Fonte: PHYTOTHERAPY RESEARCH Publicador: PHYTOTHERAPY RESEARCH
Tipo: Artigo de Revista Científica
ENG
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Infections caused by multiresistant bacterial pathogens are a significant problem worldwide, turning the search for natural compounds to act as alternatives to antibiotics of major importance. The aim of the present study was to investigate the in vitro antimicrobial activity of 7α-acetoxy-6β-hydroxyroyleanone (1), isolated from Plectranthus grandidentatus (Lamiaceae), and 11 additional royleanone abietane derivatives of 1 (2–12) against important Gram-positive human bacterial pathogens. Results showed that the aromatic and alkylic esters 2, 3 and 5 are more active than 1 against Enterococcus and Staphylococcus (minimum inhibitory concentration (MIC) values ranging from 0.98 to 62.50 µg/mL). Moreover, 7α-acetoxy-6β-hydroxy-12-O-(4-chloro)benzoylroyleanone (2) gave rise to a new antibacterial-prototype (MIC values of 3.91–15.63 µg/mL against Staphylococcus and of 0.98–3.91 µg/mL against Enterococcus). The results showed that the compounds under analysis also present antimicrobial activity against resistant bacteria. The hydrophobic extra-interactions with bacterial targets seem to play an important role on the activity of royleanones derivatives.

Molecular Epidemiologic Typing Systems of Bacterial Pathogens: Current Issues and Perpectives

Struelens,Marc J
Fonte: Instituto Oswaldo Cruz, Ministério da Saúde Publicador: Instituto Oswaldo Cruz, Ministério da Saúde
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/09/1998 EN
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The epidemiologic typing of bacterial pathogens can be applied to answer a number of different questions: in case of outbreak, what is the extent and mode of transmission of epidemic clone(s )? In case of long-term surveillance, what is the prevalence over time and the geographic spread of epidemic and endemic clones in the population? A number of molecular typing methods can be used to classify bacteria based on genomic diversity into groups of closely-related isolates (presumed to arise from a common ancestor in the same chain of transmission) and divergent, epidemiologically-unrelated isolates (arising from independent sources of infection). Ribotyping, IS-RFLP fingerprinting, macrorestriction analysis of chromosomal DNA and PCR-fingerprinting using arbitrary sequence or repeat element primers are useful methods for outbreak investigations and regional surveillance. Library typing systems based on multilocus sequence-based analysis and strain-specific probe hybridization schemes are in development for the international surveillance of major pathogens like Mycobacterium tuberculosis. Accurate epidemiological interpretation of data obtained with molecular typing systems still requires additional research on the evolution rate of polymorphic loci in bacterial pathogens.

Fecal indicators and bacterial pathogens in bottled water from Dhaka, Bangladesh

Ahmed,W.; Yusuf,R.; Hasan,I.; Ashraf,W.; Goonetilleke,A.; Toze,S.; Gardner,T.
Fonte: Sociedade Brasileira de Microbiologia Publicador: Sociedade Brasileira de Microbiologia
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2013 EN
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681.622%
Forty-six bottled water samples representing 16 brands from Dhaka, Bangladesh were tested for the numbers of total coliforms, fecal indicator bacteria (i.e., thermotolerant Escherichia coli and Enterococcus spp.) and potential bacterial pathogens (i.e., Aeromonas hydrophil, Pseudomonas aeruginos, Salmonella spp., and Shigella spp.). Among the 16 brands tested, 14 (86%), ten (63%) and seven (44%) were positive for total coliforms, E. coil and Enterococcus spp., respectively. Additionally, a further nine (56%), eight (50%), six (37%), and four (25%) brands were PCR positive for A. hydrophila lip, P. aeruginosa ETA, Salmonella spp. invA, and Shigella spp. ipaH genes, respectively. The numbers of bacterial pathogens in bottled water samples ranged from 28 ± 12 to 600 ± 45 (A. hydrophila lip gene), 180 ± 40 to 900 ± 200 (Salmonella spp. invA gene), 180 ± 40 to 1,300 ± 400 (P. aeruginosa ETA gene) genomic units per L of water. Shigella spp. ipaH gene was not quantifiable. Discrepancies were observed in terms of the occurrence of fecal indicators and bacterial pathogens. No correlations were observed between fecal indicators numbers and presence/absence of A. hydrophila lip (p = 0.245), Salmonella spp. invA (p = 0.433), Shigella spp. ipaH gene (p = 0.078)...

Bacterial Pathogens Induce Abscess Formation by CD4+ T-Cell Activation via the CD28–B7-2 Costimulatory Pathway

Tzianabos, Arthur O.; Chandraker, Anil; Kalka-Moll, Wiltrud; Stingele, Francesca; Dong, Victor M.; Finberg, Robert W.; Peach, Robert; Sayegh, Mohamed H.
Fonte: American Society for Microbiology Publicador: American Society for Microbiology
Tipo: Artigo de Revista Científica
Publicado em /12/2000 EN
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Abscesses are a classic host response to infection by many pathogenic bacteria. The immunopathogenesis of this tissue response to infection has not been fully elucidated. Previous studies have suggested that T cells are involved in the pathologic process, but the role of these cells remains unclear. To delineate the mechanism by which T cells mediate abscess formation associated with intra-abdominal sepsis, the role of T-cell activation and the contribution of antigen-presenting cells via CD28-B7 costimulation were investigated. T cells activated in vitro by zwitterionic bacterial polysaccharides (Zps) known to induce abscess formation required CD28-B7 costimulation and, when adoptively transferred to the peritoneal cavity of naïve rats, promoted abscess formation. Blockade of T-cell activation via the CD28-B7 pathway in animals with CTLA4Ig prevented abscess formation following challenge with different bacterial pathogens, including Staphylococcus aureus, Bacteroides fragilis, and a combination of Enterococcus faecium and Bacteroides distasonis. In contrast, these animals had an increased abscess rate following in vivo T-cell activation via CD28 signaling. Abscess formation in vivo and T-cell activation in vitro required costimulation by B7-2 but not B7-1. These results demonstrate that abscess formation by pathogenic bacteria is under the control of a common effector mechanism that requires T-cell activation via the CD28–B7-2 pathway.

Bacterial pathogens modulate an apoptosis differentiation program in human neutrophils

Kobayashi, Scott D.; Braughton, Kevin R.; Whitney, Adeline R.; Voyich, Jovanka M.; Schwan, Tom G.; Musser, James M.; DeLeo, Frank R.
Fonte: National Academy of Sciences Publicador: National Academy of Sciences
Tipo: Artigo de Revista Científica
EN
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483.7621%
Human polymorphonuclear leukocytes (PMNs or neutrophils) are essential to the innate immune response against bacterial pathogens. Recent evidence suggests that PMN apoptosis facilitates resolution of inflammation during bacterial infection. Although progress has been made toward understanding apoptosis in neutrophils, very little is known about transcriptional regulation of this process during bacterial infection. To gain insight into the molecular processes that facilitate resolution of infection, we measured global changes in PMN gene expression during phagocytosis of a diverse group of bacterial pathogens. Genes encoding key effectors of apoptosis were up-regulated, and receptors critical to innate immune function were down-regulated during apoptosis induced by phagocytosis of Burkholderia cepacia, Borrelia hermsii, Listeria monocytogenes, Staphylococcus aureus, and Streptococcus pyogenes. Importantly, we identified genes that comprise a common apoptosis differentiation program in human PMNs after phagocytosis of pathogenic bacteria. Unexpectedly, phagocytosis of Str. pyogenes induced changes in neutrophil gene expression not observed with other pathogens tested, including down-regulation of 21 genes involved in responses to IFN. Compared with other bacteria...

Phages and the Evolution of Bacterial Pathogens: from Genomic Rearrangements to Lysogenic Conversion

Brüssow, Harald; Canchaya, Carlos; Hardt, Wolf-Dietrich
Fonte: American Society for Microbiology Publicador: American Society for Microbiology
Tipo: Artigo de Revista Científica
Publicado em /09/2004 EN
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Comparative genomics demonstrated that the chromosomes from bacteria and their viruses (bacteriophages) are coevolving. This process is most evident for bacterial pathogens where the majority contain prophages or phage remnants integrated into the bacterial DNA. Many prophages from bacterial pathogens encode virulence factors. Two situations can be distinguished: Vibrio cholerae, Shiga toxin-producing Escherichia coli, Corynebacterium diphtheriae, and Clostridium botulinum depend on a specific prophage-encoded toxin for causing a specific disease, whereas Staphylococcus aureus, Streptococcus pyogenes, and Salmonella enterica serovar Typhimurium harbor a multitude of prophages and each phage-encoded virulence or fitness factor makes an incremental contribution to the fitness of the lysogen. These prophages behave like “swarms” of related prophages. Prophage diversification seems to be fueled by the frequent transfer of phage material by recombination with superinfecting phages, resident prophages, or occasional acquisition of other mobile DNA elements or bacterial chromosomal genes. Prophages also contribute to the diversification of the bacterial genome architecture. In many cases, they actually represent a large fraction of the strain-specific DNA sequences. In addition...

Influence of Gastric Acid on Susceptibility to Infection with Ingested Bacterial Pathogens▿

Tennant, Sharon M.; Hartland, Elizabeth L.; Phumoonna, Tongted; Lyras, Dena; Rood, Julian I.; Robins-Browne, Roy M.; van Driel, Ian R.
Fonte: American Society for Microbiology (ASM) Publicador: American Society for Microbiology (ASM)
Tipo: Artigo de Revista Científica
EN
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574.78465%
Despite the widely held belief that gastric acid serves as a barrier to bacterial pathogens, there are almost no experimental data to support this hypothesis. We have developed a mouse model to quantify the effectiveness of gastric acid in mediating resistance to infection with ingested bacteria. Mice that were constitutively hypochlorhydric due to a mutation in a gastric H+/K+-ATPase (proton pump) gene were infected with Yersinia enterocolitica, Salmonella enterica serovar Typhimurium, Citrobacter rodentium, or Clostridium perfringens cells or spores. Significantly greater numbers of Yersinia, Salmonella, and Citrobacter cells (P ≤ 0.006) and Clostridium spores (P = 0.02) survived in hypochlorhydric mice, resulting in reduced median infectious doses. Experiments involving intraperitoneal infection or infection of mice treated with antacids indicated that the increased sensitivity of hypochlorhydric mice to infection was entirely due to the absence of stomach acid. Apart from establishing the role of gastric acid in nonspecific immunity to ingested bacterial pathogens, our model provides an excellent system with which to investigate the effects of hypochlorhydria on susceptibility to infection and to evaluate the in vivo susceptibility to gastric acid of orally administered therapies...

Inducible Resistance of Fish Bacterial Pathogens to the Antimicrobial Peptide Cecropin B▿

Sallum, Ulysses W.; Chen, Thomas T.
Fonte: American Society for Microbiology (ASM) Publicador: American Society for Microbiology (ASM)
Tipo: Artigo de Revista Científica
EN
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Cecropin B is a cationic antimicrobial peptide originally isolated from the diapausing pupae of the giant silk moth, Hylphora cecropia. Cecropin B elicits its antimicrobial effects through disruption of the anionic cell membranes of gram-negative bacteria. Previous work by our laboratory demonstrated that a constitutively expressed cecropin B transgene conferred enhanced resistance to bacterial infection in medaka. The development of antibiotic resistance by pathogenic bacteria is a growing problem. The potential for fish bacterial pathogens to develop resistance to cecropin B was addressed in this study. Four fish bacterial pathogens were selected for the study based on their importance in aquaculture. Vibrio anguillarum, Vibrio vulnificus, and Yersinia ruckeri all exhibited inducible resistance to cecropin B. The inducible resistance of these three pathogens was correlated with reversible changes in their ultrastructures, as observed by scanning electron microscopy. V. anguillarum was demonstrated to become more adhesive to a CHSE-214 cell monolayer and to cause increased cumulative mortality in medaka following exposure to cecropin B. This work demonstrates that the resistance of fish bacterial pathogens to cecropin B is inducible and suggests that resistance to other cationic antimicrobial peptides may occur through similar means. The observed changes in ultrastructure and infectivity suggest that resistance to antimicrobial peptides is an integral part of the pathogenesis of fish gram-negative bacterial pathogens.

Platelets in defense against bacterial pathogens

Yeaman, Michael R.
Fonte: SP Birkhäuser Verlag Basel Publicador: SP Birkhäuser Verlag Basel
Tipo: Artigo de Revista Científica
EN
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483.7621%
Platelets interact with bacterial pathogens through a wide array of cellular and molecular mechanisms. The consequences of this interaction may significantly influence the balance between infection and immunity. On the one hand, recent data indicate that certain bacteria may be capable of exploiting these interactions to gain a virulence advantage. Indeed, certain bacterial pathogens appear to have evolved specific ways in which to subvert activated platelets. Hence, it is conceivable that some bacterial pathogens exploit platelet responses. On the other hand, platelets are now known to possess unambiguous structures and functions of host defense effector cells. Recent discoveries emphasize critical features enabling such functions, including expression of toll-like receptors that detect hallmark signals of bacterial infection, an array of microbicidal peptides, as well as other host defense molecules and functions. These concepts are consistent with increased risk and severity of bacterial infection as correlates of clinical abnormalities in platelet quantity and quality. In these respects, the molecular and cellular roles of platelets in host defense against bacterial pathogens are explored with attention on advances in platelet immunobiology.

Phytosterols Play a Key Role in Plant Innate Immunity against Bacterial Pathogens by Regulating Nutrient Efflux into the Apoplast1[C][W][OA]

Wang, Keri; Senthil-Kumar, Muthappa; Ryu, Choong-Min; Kang, Li; Mysore, Kirankumar S.
Fonte: American Society of Plant Biologists Publicador: American Society of Plant Biologists
Tipo: Artigo de Revista Científica
EN
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485.14867%
Bacterial pathogens colonize a host plant by growing between the cells by utilizing the nutrients present in apoplastic space. While successful pathogens manipulate the plant cell membrane to retrieve more nutrients from the cell, the counteracting plant defense mechanism against nonhost pathogens to restrict the nutrient efflux into the apoplast is not clear. To identify the genes involved in nonhost resistance against bacterial pathogens, we developed a virus-induced gene-silencing-based fast-forward genetics screen in Nicotiana benthamiana. Silencing of N. benthamiana SQUALENE SYNTHASE, a key gene in phytosterol biosynthesis, not only compromised nonhost resistance to few pathovars of Pseudomonas syringae and Xanthomonas campestris, but also enhanced the growth of the host pathogen P. syringae pv tabaci by increasing nutrient efflux into the apoplast. An Arabidopsis (Arabidopsis thaliana) sterol methyltransferase mutant (sterol methyltransferase2) involved in sterol biosynthesis also compromised plant innate immunity against bacterial pathogens. The Arabidopsis cytochrome P450 CYP710A1, which encodes C22-sterol desaturase that converts β-sitosterol to stigmasterol, was dramatically induced upon inoculation with nonhost pathogens. An Arabidopsis Atcyp710A1 null mutant compromised both nonhost and basal resistance while overexpressors of AtCYP710A1 enhanced resistance to host pathogens. Our data implicate the involvement of sterols in plant innate immunity against bacterial infections by regulating nutrient efflux into the apoplast.

Interactions of Seedborne Bacterial Pathogens with Host and Non-Host Plants in Relation to Seed Infestation and Seedling Transmission

Dutta, Bhabesh; Gitaitis, Ronald; Smith, Samuel; Langston, David
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: Artigo de Revista Científica
Publicado em 17/06/2014 EN
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The ability of seed-borne bacterial pathogens (Acidovorax citrulli, Clavibacter michiganensis subsp. michiganensis, Pseudomonas syringae pv. tomato, Xanthomonas euvesicatoria, and Pseudomonas syringae pv. glycinea) to infest seeds of host and non-host plants (watermelon, tomato, pepper, and soybean) and subsequent pathogen transmission to seedlings was investigated. A non-pathogenic, pigmented strain of Serratia marcescens was also included to assess a null-interacting situation with the same plant species. Flowers of host and non-host plants were inoculated with 1×106 colony forming units (CFUs)/flower for each bacterial species and allowed to develop into fruits or umbels (in case of onion). Seeds harvested from each host/non-host bacterial species combination were assayed for respective bacteria by plating on semi-selective media. Additionally, seedlots for each host/non-host bacterial species combination were also assayed for pathogen transmission by seedling grow-out (SGO) assays under greenhouse conditions. The mean percentage of seedlots infested with compatible and incompatible pathogens was 31.7 and 30.9% (by plating), respectively and they were not significantly different (P = 0.67). The percentage of seedlots infested with null-interacting bacterial species was 16.8% (by plating) and it was significantly lower than the infested lots generated with compatible and incompatible bacterial pathogens (P = 0.03). None of the seedlots with incompatible/null-interacting bacteria developed symptoms on seedlings; however...

Modelling host tissue degradation by extracellular bacterial pathogens

King, J.; Koerber, A.; Croft, J.; Ward, J.; Williams, P.; Sockett, R.
Fonte: Oxford Univ Press Publicador: Oxford Univ Press
Tipo: Artigo de Revista Científica
Publicado em //2003 EN
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567.30473%
Extracellular bacterial pathogens such as Pseudomonas aeruginosa are able to penetrate into host tissues (given an initial breech in the outer barrier, e.g. a wound) through the action of exo-toxins and degradative exo-enzymes. A mathematical model of this process is presented which, in the absence of significant immune response, predicts the progression of the bacteria into the tissue as a travelling wave whose velocity can be determined explicitly in terms of the model parameters. Simple in vitro experiments in protein-based matrices are performed which yield results consistent with this behaviour. A complementary in vitro experimental system with distinct qualitative behaviour is also studied, giving further insight and confidence in the modelling approach.; J. R. King and A. J. Koerber, J. M. Croft, J. P. Ward, P. Williams and R. E. Sockett

In vitro potency of doripenem tested against an international collection of rarely isolated bacterial pathogens

Jones, R.; Bell, J.; Sader, H.; Turnidge, J.; Stilwell, M.
Fonte: Elsevier Science Inc Publicador: Elsevier Science Inc
Tipo: Artigo de Revista Científica
Publicado em //2009 EN
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571.31633%
Doripenem, a new 1beta-methyl parenteral carbapenem, has very broad-spectrum activity against Gram-positive and Gram-negative aerobic bacteria. As noted here, the spectrum and potency extended to many rarely isolated species sampled by the Doripenem Global Surveillance Program. Among the species or species groups with 0.25 microg/mL for all tested species except Lactococcus garvieae, Listeria monocytogenes, and Micrococcus spp. In conclusion, doripenem exhibited a very wide spectrum but variable potencies against uncommonly cultured aerobic bacterial pathogens isolated in 2003 to 2007. These results confirm the potential use of this new carbapenem for broad-spectrum empiric or directed antimicrobial therapy.; Ronald N. Jones...

Wzy-dependent bacterial capsules as potential drug targets

Ericsson, D.; Standish, A.; Kobe, B.; Morona, R.
Fonte: Bentham Science Publishers Ltd. Publicador: Bentham Science Publishers Ltd.
Tipo: Artigo de Revista Científica
Publicado em //2012 EN
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The bacterial capsule is a recognized virulence factor in pathogenic bacteria. It likely works as an antiphagocytic barrier by minimizing complement deposition on the bacterial surface. With the continual rise of bacterial pathogens resistant to multiple antibiotics, there is an increasing need for novel drugs. In the Wzy-dependent pathway, the biosynthesis of capsular polysaccharide (CPS) is regulated by a phosphoregulatory system, whose main components consist of bacterial-tyrosine kinases (BY-kinases) and their cognate phosphatases. The ability to regulate capsule biosynthesis has been shown to be vital for pathogenicity, because different stages of infection require a shift in capsule thickness, making the phosphoregulatory proteins suitable as drug targets. Here, we review the role of regulatory proteins focusing on Streptococcus pneumoniae, Staphylococcus aureus, and Escherichia coli and discuss their suitability as targets in structure-based drug design.; Daniel J. Ericsson, Alistair Standish, Bostjan Kobe, and Renato Morona

Engineering Escherichia coli K-­12 for the secretion of single domain antibodies against attaching and effacing bacterial pathogens and for the injection of proteins of therapeutic potential into human cells

Ruano Gallego, David
Fonte: Universidade Autônoma de Madrid Publicador: Universidade Autônoma de Madrid
Tipo: Tese de Doutorado
ENG
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484.25984%
Tesis doctoral inédita leída en la Universidad Autónoma de Madrid, Facultad de Ciencias, Departamento de Biología Molecular. Fecha de lectura: 12-12-2014; The attaching and effacing (A/E) bacterial pathogens infect the gastrointestinal tract of humans and other mammals after ingestion of contaminated food or water and cause persistent diarrhoea and other important diseases (e.g. haemolytic uremic syndrome, HUS) worldwide. Prototypical A/E pathogens are the enteropathogenic Escherichia coli (EPEC) and enterohaemorrhagic E. coli (EHEC) strains, which infect humans, as well as the mouse-­‐restricted pathogen Citrobacter rodentium (CR). These pathogens contain a common type III secretion system (T3SS): a macromolecular protein complex (the injectisome) assembled in the bacterial cell envelope that protrudes to the extracellular milieu with a filament of polymerized EspA. The T3SS allows translocation (injection) of a repertoire of bacterial proteins (called effectors) into the cytoplasm of the host enterocytes through the translocon subunits EspB and EspD, which insert in the host cell membrane. The effectors subvert multiple cellular functions and cause the effacement of the intestinal microvilli (A/E lesions) and the disruption of the intestinal epithelial barrier. Among them...

The neglected intrinsic resistome of bacterial pathogens

Fajardo, A.; Martínez-Martín, Nadia; Mercadillo, María; Galán, Juan Carlos; Ghysels, Bart; Matthijs, Sandra; Cornelis, Pierre; Wiehlmann, Lutz; Tümmler, Burkhard; Baquero, Fernando; Martínez, José L.
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: Artículo Formato: 167420 bytes; application/pdf
ENG
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674.7847%
6 pages, 2 figures, 2 tables.-- PMID: 18286176 [PubMed].-- PMCID: PMC2238818.; Supporting information (Suppl. table S1) available at: http://www.plosone.org/article/fetchSingleRepresentation.action?uri=info:doi/10.1371/journal.pone.0001619.s001; Bacteria with intrinsic resistance to antibiotics are a worrisome health problem. It is widely believed that intrinsic antibiotic resistance of bacterial pathogens is mainly the consequence of cellular impermeability and activity of efflux pumps. However, the analysis of transposon-tagged Pseudomonas aeruginosa mutants presented in this article shows that this phenotype emerges from the action of numerous proteins from all functional categories. Mutations in some genes make P. aeruginosa more susceptible to antibiotics and thereby represent new targets. Mutations in other genes make P. aeruginosa more resistant and therefore define novel mechanisms for mutation-driven acquisition of antibiotic resistance, opening a new research field based in the prediction of resistance before it emerges in clinical environments. Antibiotics are not just weapons against bacterial competitors, but also natural signalling molecules. Our results demonstrate that antibiotic resistance genes are not merely protective shields and offer a more comprehensive view of the role of antibiotic resistance genes in the clinic and in nature.; This work was supported by grants BIO2005-04278...

Hijacking of eukaryotic functions by intracellular bacterial pathogens; Secuestro de funciones eucarióticas por patógenos intracelulares bacterianos

Alonso, Ana; García del Portillo, Francisco
Fonte: Sociedad Española de Microbiología Publicador: Sociedad Española de Microbiología
Tipo: Artículo
ENG
Relevância na Pesquisa
682.8407%
Intracellular bacterial pathogens have evolved as a group of microorganisms endowed with weapons to hijack many biological processes of eukaryotic cells. This review discusses how these pathogens perturb diverse host cell functions, such as cytoskeleton dynamics and organelle vesicular trafficking. Alteration of the cytoskeleton is discussed in the context of the bacterial entry process (invasion), which occurs either by activation of membrane-located host receptors ("zipper" mechanism) or by injection of bacterial proteins into the host cell cytosol ("trigger" mechanism). In addition, the two major types of intracellular lifestyles, cytosolic versus intravacuolar phagosomal), which are the consequence of alterations in the phagosome-lysosome maturation route, are compared. Specific examples illustrating known mechanisms of mimicry or hijacking of the host target are provided. Finally, recent advances in phagosome proteomics and genome expression in intracellular bacteria are described. These new technologies are yielding valuable clues as to how these specialized bacterial pathogens manipulate the mammalian host cell.; Los patógenos bacterianos intracelulares han evolucionado como un grupo de microorganismos altamente especializados en el secuestro de funciones propias de células eucariotas. Esta revisión discute cómo esos patógenos alteran diversas funciones de la célula hospedadora...

Hijacking of eukaryotic functions by intracellular bacterial pathogens

Alonso,Ana; García-del Portillo,Francisco
Fonte: International Microbiology Publicador: International Microbiology
Tipo: info:eu-repo/semantics/article; journal article; info:eu-repo/semantics/publishedVersion Formato: text/html; application/pdf
Publicado em 01/09/2004 ENG
Relevância na Pesquisa
682.8407%
Intracellular bacterial pathogens have evolved as a group of microorganisms endowed with weapons to hijack many biological processes of eukaryotic cells. This review discusses how these pathogens perturb diverse host cell functions, such as cytoskeleton dynamics and organelle vesicular trafficking. Alteration of the cytoskeleton is discussed in the context of the bacterial entry process (invasion), which occurs either by activation of membrane-located host receptors ("zipper" mechanism) or by injection of bacterial proteins into the host cell cytosol ("trigger" mechanism). In addition, the two major types of intracellular lifestyles, cytosolic versus intravacuolar (phagosomal), which are the consequence of alterations in the phagosome-lysosome maturation route, are compared. Specific examples illustrating known mechanisms of mimicry or hijacking of the host target are provided. Finally, recent advances in phagosome proteomics and genome expression in intracellular bacteria are described. These new technologies are yielding valuable clues as to how these specialized bacterial pathogens manipulate the mammalian host cell.

Optimisation of methods for the collection and detection of bacterial pathogens from diarrhoeal human faecal samples using a novel stool collection kit

Mieta,SIK; Potgieter,N; Sobsey,MD; Barnard,TG
Fonte: Water SA Publicador: Water SA
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2010 EN
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688.00984%
Bacterial pathogens such as Escherichia coli, Salmonella-, Shigella- and Vibrio species are known to be common causative agents for diarrhoeal disease in humans. This study aimed to develop a culture-independent PCR assay for the detection of bacterial pathogens present in human faecal samples collected using a less intrusive faecal collection technique, the Bio-wipe kit. A multiplex-PCR (m-PCR) was optimised targeting the E. coli mdh gene, the Salmonella IpaB gene, the Vibrio sodB gene, and the Ial and IpaH genes present in entero-invasive E. coli and Shigella spp. The influence of the DNA extraction method, and sensitivity and specificity of the m-PCR and the Bio-wipe storage conditions on the detection of the bacterial pathogens was investigated. A guanidium thiocyanate DNA extraction method used with laboratory-prepared spin columns could successfully extract DNA from 93% of the samples analysed. The m-PCR could successfully identify and differentiate between the various pathogens tested and was specific for the selected pathogens. Faecal matter was successfully recovered from used Bio-wipes and the bacterial DNA could be detected from these samples at concentrations of 10 cfu. Bacterial DNA could be recovered from the Bio-wipes 5 to 10 d after use when the Bio-wipes were stored at 30°C and 14 d after usage when stored at ambient temperature. Thus the Bio-wipe kit...

Antibiotic resistance among pathogens causing disease in Jamaican children with HIV/AIDS

Byam,PR; Pierre,RB; Christie,CDC; Andiman,WA; Pettigrew,M
Fonte: West Indian Medical Journal Publicador: West Indian Medical Journal
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/07/2010 EN
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580.76086%
OBJECTIVE: There are limited data regarding the antimicrobial resistance patterns of pathogens in children with HIV/AIDS from developing countries. We aimed to determine the prevalence and antibiotic susceptibility patterns of bacterial pathogens causing urinary tract infections (UTIs) and sepsis in a cohort of 219 HIV-infected Jamaican children. METHODS: This cross-sectional study examined clinical and microbiological data for children enrolled in the Kingston Paediatric/Perinatal HIV/AIDS programme from September 1, 2002 to May 31, 2007. Cases were defined as physician-diagnosed, laboratory confirmed UTIs and sepsis based on Centers for Disease Control and Prevention (CDC) criteria. Only isolates from urine, blood and sterile sites were considered. RESULTS: Forty-four patients (20.1%) accounted for 74 episodes of UTIs and sepsis. Mean number of infections was 1.7 ± 1.3 per patient. There were 31 males (70.5%) and mean age at time of infection was 5.6 ± 4.7 years. Bacterial infections comprised cystitis (n = 52, 70.3%), bacterial pneumonia (n = 15, 20.3%), meningitis (n = 4, 5.4%), septicaemia (n = 2, 2.7%) and bone infection (n = 1, 1.4%). Among 52 UTIs, 39 were caused by a single organism. The most common UTI isolates included Escherichia coli (n = 21...