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31 results on '"Cerqueira, Gustavo M."'

8. Leptospira noguchii and human and animal leptospirosis, southern Brazil

Author

Silva, Everton F., Cerqueira, Gustavo M., Seyffert, Nubia, Seixas, Fabiana K., Hartwig, Daiane D., Athanazio, Daniel A., Pinto, Luciano S., Queiroz, Adriano, Ko, Albert I., Brod, Claudiomar S., and Dellagostin, Odir A.

Subjects
Company distribution practices, Epidemics -- Brazil, Epidemics -- Research, Leptospirosis -- Causes of, Leptospirosis -- Diagnosis, Leptospirosis -- Distribution, Leptospirosis -- Research
Abstract

To the Editor: Pathogenic leptospires, the causative agents of leptospirosis, exhibit wide phenotypic and genotypic variations. They are currently classified into 17 species and >200 serovars (1,2). Most reported cases [...]

Published
2009

9. Expanding the genetic toolbox for Leptospira species by generation of fluorescent bacteria

Author

Aviat, Florence, Slamti, Leyla, Cerqueira, Gustavo M., Lourdault, Kristel, and Picardeau, Mathieu

Subjects
Bacteria, Pathogenic -- Genetic aspects, Bacteria, Pathogenic -- Physiological aspects, Gene expression -- Research, Green fluorescent protein -- Research, Biological sciences
Abstract

Fluorescence microscopy and a fluorometric microplate reader-based assay are used to measure the fluorescence of Leptospira and understand the effect of the green fluorescent protein (gfp) gene on growth in vivo and pathogenicity in L. interrogans. The findings for expression of gfp and mRFP1 genes under the control of constitutive spirochetal promoters in both saprophytic and pathogenic Leptospira strains demonstrated the possible application of gfp as a reporter to assess promoter activity in different environmental conditions.

Published
2010

11. American Journal of Tropical Medicine and Hygiene

Author

Cerqueira, Gustavo M., McBride, Alan J. A., Queiroz, Adriano, Pinto, Luciano S., Silva, Éverton F., Hartskeerl, Rudy A., Reis, Mitermayer G., Ko, Albert I., and Dellagostin, Odir Antonio

Subjects
Leptospira, Contaminação, Contamination, Leptospirosis, Leptospirose
Abstract

Texto completo: acesso restrito. p.83-87 Submitted by Suelen Reis (suziy.ellen@gmail.com) on 2013-09-11T13:14:58Z No. of bitstreams: 1 2010.09-0558.pdf: 485495 bytes, checksum: b03bac0e10bd69c6989e1ca198a5b1c1 (MD5) Approved for entry into archive by Vilma Conceição(vilmagc@ufba.br) on 2013-09-13T17:18:48Z (GMT) No. of bitstreams: 1 2010.09-0558.pdf: 485495 bytes, checksum: b03bac0e10bd69c6989e1ca198a5b1c1 (MD5) Made available in DSpace on 2013-09-13T17:18:48Z (GMT). No. of bitstreams: 1 2010.09-0558.pdf: 485495 bytes, checksum: b03bac0e10bd69c6989e1ca198a5b1c1 (MD5) Previous issue date: 2010 The purpose of this study was to perform a 16S sequence-based quality control of two Leptospira strain collections. 16S rRNA gene sequencing was used to verify two Leptospira reference collections provided by the World Health Organization and maintained at a reference laboratory for leptospirosis in Brazil. Among the 89 serovars evaluated, four conflicting strains were identified in one of the collections. Although 16S rRNA gene sequencing cannot identify Leptospira beyond the species level, it is suitable for the identification of contamination and quality control of leptospiral reference collections. This study highlights the importance of the availability of high-quality 16S rRNA sequences in public databases. In addition, it emphasizes the need for periodical verifications and quality control of Leptospira reference collections.

Published
2010
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12. The Success of Acinetobacter Species; Genetic, Metabolic and Virulence Attributes

Author

Peleg, Anton Y., de Breij, Anna, Adams, Mark D., Cerqueira, Gustavo M., Mocali, Stefano, Galardini, Marco, Nibbering, Peter H., Earl, Ashlee M., Ward, Doyle V., Paterson, David L., Seifert, Harald, Dijkshoorn, Lenie, Peleg, Anton Y., de Breij, Anna, Adams, Mark D., Cerqueira, Gustavo M., Mocali, Stefano, Galardini, Marco, Nibbering, Peter H., Earl, Ashlee M., Ward, Doyle V., Paterson, David L., Seifert, Harald, and Dijkshoorn, Lenie

Abstract

An understanding of why certain Acinetobacter species are more successful in causing nosocomial infections, transmission and epidemic spread in healthcare institutions compared with other species is lacking. We used genomic, phenotypic and virulence studies to identify differences between Acinetobacter species. Fourteen strains representing nine species were examined. Genomic analysis of six strains showed that the A. baumannii core genome contains many genes important for diverse metabolism and survival in the host. Most of the A. baumannii core genes were also present in one or more of the less clinically successful species. In contrast, when the accessory genome of an individual A. baumannii strain was compared to a strain of a less successful species (A. calcoaceticus RUH2202), many operons with putative virulence function were found to be present only in the A. baumannii strain, including the csu operon, the acinetobactin chromosomal cluster, and bacterial defence mechanisms. Phenotype microarray analysis showed that compared to A. calcoaceticus (RUH2202), A. baumannii ATCC 19606(T) was able to utilise nitrogen sources more effectively and was more tolerant to pH, osmotic and antimicrobial stress. Virulence differences were also observed, with A. baumannii ATCC 19606(T), A. pittii SH024, and A. nosocomialis RUH2624 persisting and forming larger biofilms on human skin than A. calcoaceticus. A. baumannii ATCC 19606 T and A. pittii SH024 were also able to survive in a murine thigh infection model, whereas the other two species were eradicated. The current study provides important insights into the elucidation of differences in clinical relevance among Acinetobacter species.

Published
2012

14. The Success of Acinetobacter Species; Genetic, Metabolic and Virulence Attributes

Author

Peleg, Anton Y., primary, de Breij, Anna, additional, Adams, Mark D., additional, Cerqueira, Gustavo M., additional, Mocali, Stefano, additional, Galardini, Marco, additional, Nibbering, Peter H., additional, Earl, Ashlee M., additional, Ward, Doyle V., additional, Paterson, David L., additional, Seifert, Harald, additional, and Dijkshoorn, Lenie, additional

Published
2012
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25. Leptospira noguchiiand Human and Animal Leptospirosis, Southern Brazil

Author

Silva, Éverton F., primary, Cerqueira, Gustavo M., additional, Seyffert, Núbia, additional, Seixas, Fabiana K., additional, Hartwig, Daiane D., additional, Athanazio, Daniel A., additional, Pinto, Luciano S., additional, Queiroz, Adriano, additional, Ko, Albert I., additional, Brod, Claudiomar S., additional, and Dellagostin, Odir A., additional

Published
2009
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27. Genome-Wide Transposon Mutagenesis in Pathogenic Leptospira Species

Author

Murray, Gerald L., primary, Morel, Viviane, additional, Cerqueira, Gustavo M., additional, Croda, Julio, additional, Srikram, Amporn, additional, Henry, Rebekah, additional, Ko, Albert I., additional, Dellagostin, Odir A., additional, Bulach, Dieter M., additional, Sermswan, Rasana W., additional, Adler, Ben, additional, and Picardeau, Mathieu, additional

Published
2009
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29. Impact of a Cross-Kingdom Signaling Molecule of Candida albicanson Acinetobacter baumanniiPhysiology

Author

Kostoulias, Xenia, Murray, Gerald L., Cerqueira, Gustavo M., Kong, Jason B., Bantun, Farkad, Mylonakis, Eleftherios, Khoo, Chen Ai, and Peleg, Anton Y.

Abstract

ABSTRACTMultidrug-resistant (MDR) Acinetobacter baumanniiis an opportunistic human pathogen that has become highly problematic in the clinical environment. Novel therapies are desperately required. To assist in identifying new therapeutic targets, the antagonistic interactions between A. baumanniiand the most common human fungal pathogen, Candida albicans, were studied. We have observed that the C. albicansquorum-sensing molecule, farnesol, has cross-kingdom interactions, affecting the viability of A. baumannii. To gain an understanding of its mechanism, the transcriptional profile of A. baumanniiexposed to farnesol was examined. Farnesol caused dysregulation of a large number of genes involved in cell membrane biogenesis, multidrug efflux pumps (AcrAB-like and AdeIJK-like), and A. baumanniivirulence traits such as biofilm formation (csuA, csuB, and ompA) and motility (pilZand pilH). We also observed a strong induction in genes involved in cell division (minD, minE, ftsK, ftsB, and ftsL). These transcriptional data were supported by functional assays showing that farnesol disrupts A. baumanniicell membrane integrity, alters cell morphology, and impairs virulence characteristics such as biofilm formation and twitching motility. Moreover, we showed that A. baumanniiuses efflux pumps as a defense mechanism against this eukaryotic signaling molecule. Owing to its effects on membrane integrity, farnesol was tested to see if it potentiated the activity of the membrane-acting polymyxin antibiotic colistin. When coadministered, farnesol increased sensitivity to colistin for otherwise resistant strains. These data provide mechanistic understanding of the antagonistic interactions between diverse pathogens and may provide important insights into novel therapeutic strategies.

Published
2015
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30. Inactivation of clpBin the Pathogen Leptospira interrogansReduces Virulence and Resistance to Stress Conditions

Author

Lourdault, Kristel, Cerqueira, Gustavo M., Wunder, Elsio A., and Picardeau, Mathieu

Abstract

ABSTRACTLeptospira interrogansis the causative agent of leptospirosis, which is an emerging zoonotic disease. Resistance to stress conditions is largely uncharacterized for this bacterium. We therefore decided to analyze a clpBmutant that we obtained by random transposon mutagenesis. The mutant did not produce any of the two isoforms of ClpB. The clpBmutant exhibited growth defects at 30° and 37°C and in poor nutrient medium and showed increased susceptibility to oxidative stress, whereas the genetically complemented strain was restored in ClpB expression and in vitrowild-type growth. We also showed that the clpBmutant was attenuated in virulence in an animal model of acute leptospirosis. Our findings demonstrate that ClpB is involved in the general stress response. The chaperone is also necessary, either directly or indirectly, for the virulence of the pathogen L. interrogans.

Published
2011
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31. Impact of a Cross-Kingdom Signaling Molecule of Candida albicans on Acinetobacter baumannii Physiology.

Author

Kostoulias X, Murray GL, Cerqueira GM, Kong JB, Bantun F, Mylonakis E, Khoo CA, and Peleg AY

Subjects
Acinetobacter baumannii genetics, Acinetobacter baumannii metabolism, Anti-Bacterial Agents pharmacology, Antibiosis, Bacterial Proteins antagonists & inhibitors, Bacterial Proteins genetics, Bacterial Proteins metabolism, Biofilms growth & development, Candida albicans physiology, Cell Membrane drug effects, Colistin pharmacology, Drug Synergism, Farnesol metabolism, Genes, MDR, Quorum Sensing, Acinetobacter baumannii drug effects, Biofilms drug effects, Candida albicans pathogenicity, Farnesol pharmacology, Gene Expression Regulation, Bacterial, Transcriptome drug effects
Abstract

Multidrug-resistant (MDR) Acinetobacter baumannii is an opportunistic human pathogen that has become highly problematic in the clinical environment. Novel therapies are desperately required. To assist in identifying new therapeutic targets, the antagonistic interactions between A. baumannii and the most common human fungal pathogen, Candida albicans, were studied. We have observed that the C. albicans quorum-sensing molecule, farnesol, has cross-kingdom interactions, affecting the viability of A. baumannii. To gain an understanding of its mechanism, the transcriptional profile of A. baumannii exposed to farnesol was examined. Farnesol caused dysregulation of a large number of genes involved in cell membrane biogenesis, multidrug efflux pumps (AcrAB-like and AdeIJK-like), and A. baumannii virulence traits such as biofilm formation (csuA, csuB, and ompA) and motility (pilZ and pilH). We also observed a strong induction in genes involved in cell division (minD, minE, ftsK, ftsB, and ftsL). These transcriptional data were supported by functional assays showing that farnesol disrupts A. baumannii cell membrane integrity, alters cell morphology, and impairs virulence characteristics such as biofilm formation and twitching motility. Moreover, we showed that A. baumannii uses efflux pumps as a defense mechanism against this eukaryotic signaling molecule. Owing to its effects on membrane integrity, farnesol was tested to see if it potentiated the activity of the membrane-acting polymyxin antibiotic colistin. When coadministered, farnesol increased sensitivity to colistin for otherwise resistant strains. These data provide mechanistic understanding of the antagonistic interactions between diverse pathogens and may provide important insights into novel therapeutic strategies., (Copyright © 2015, American Society for Microbiology. All Rights Reserved.)

Published
2015
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