Epidemiological characterization, antimicrobial resistance and virulence mechanisms of human and animal streptococci

Bibliographic Details
Main Author: Rato, Márcia Alexandra Gonçalves
Publication Date: 2011
Language: eng
Source: Repositórios Científicos de Acesso Aberto de Portugal (RCAAP)
Download full: http://hdl.handle.net/10362/7501
Summary: Dissertação para obtenção do Grau de Doutor em Biologia
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spelling Epidemiological characterization, antimicrobial resistance and virulence mechanisms of human and animal streptococciStreptococcus agalactiaeStreptococcus dysgalactiae subsp. dysgalactiaeStreptococcus uberisMolecular typingAntimicrobial resistanceVirulenceDissertação para obtenção do Grau de Doutor em BiologiaStreptococcus agalactiae (Group B Streptococcus - GBS), Streptococcus dysgalactiae subsp. dysgalactiae (Group C Streptococcus - GCS) and Streptococcus uberis are relevant mastitis pathogens, a highly prevalent and costly disease in the dairy industry due to antibiotherapy and loss in milk production. However, molecular characterization of field isolates of Streptococcus spp. occurring in Portugal was not known prior to our studies and is important to improve therapeutic and disease control programs. The aims of this study were the identification of strain molecular features, and the evaluation of antimicrobial drug resistance patterns of S. agalactiae (n=60), S. dysgalactiae subsp. dysgalactiae (n=18) and S. uberis (n=30) collected from bovine subclinical mastitis between 2002/2003 in Portugal. Additionally, two S. dysgalactiae subsp. dysgalactiae strains associated with invasive disease(one collected from cattle and the other from a human), and six Streptococcus dysgalactiae subsp. equisimilis (group C or group G Streptococcus - GCS/GGS) strains from human infection were included in the study, for comparative purposes. Genotypic relationships were identified using pulsed-field gel electrophoresis (PFGE)/BioNumerics, S. agalactiae and S. uberis multi-locus sequence typing (MLST), macrolide and tetracycline resistance gene profiling, S. agalactiae molecular serotyping, virulence gene profiling, PCR-amplification for screening presence of specific genes and subsequent sequencing for phylogenetic analysis, and reverse transcriptase-PCR (RT-PCR) for gene expression analysis of selected genes. Also, a custom-designed microarray containing 220 virulence genes of the human pathogen Streptococcus pyogenes (Group A Streptococcus - GAS) was used to test bovine GCS S. dysgalactiae subsp. dysgalactiae and human GCS/GGS S.dysgalactiae subsp. equisimilis. Antimicrobial resistance was assessed by disk diffusion against penicillin, gentamicin, streptomycin, amoxicillin-clavulanic acid, cefazolin, cefoperazone,rifaximin, erythromycin, pirlimycin, tetracycline, vancomycin, chloramphenicol and the macrolide lincosamide resistance phenotypes (cMLSB, iMLSB, M, L). Among S. uberis three PFGE clonal groups (defined by at least 80% similarity) comprised almost half of total isolates, and 50% of GBS isolates were included in four major clonal groups (all farm-associated), which is indicative of a contagious route of transmission between animals. The occurrence of PFGE patterns sharing >82.8% and 100% similarity among S. dysgalactiae subsp. dysgalactiae isolates collected from different farms suggests an environmental source for this pathogen in our case. By MLST, we observed that all S. uberis sequence types (ST) were found to be novel (n=14), representing novel genomic backgrounds for this pathogen. Among GBS only three MLST lineages (ST-2, ST-23, and ST-61/ST-554) were detected revealing little heterogeneity among our bovine GBS collection. Five new cpsD-cpsE-cpsF sequences of the cps locus (encoding the capsular polysaccharide) were detected in >70% of the bovine GBS, which may represent new serotypes.Fundação para a Ciência e a Tecnologia - Doctoral Project (SFRH/BD/32513/2006)Faculdade de Ciências e TecnologiaSanches, IldaVilela, CristinaRUNRato, Márcia Alexandra Gonçalves2012-07-19T09:01:10Z20112011-01-01T00:00:00Zdoctoral thesisinfo:eu-repo/semantics/publishedVersionapplication/pdfhttp://hdl.handle.net/10362/7501TID:101265824eng978-989-20-2618-3info:eu-repo/semantics/openAccessreponame:Repositórios Científicos de Acesso Aberto de Portugal (RCAAP)instname:FCCN, serviços digitais da FCT – Fundação para a Ciência e a Tecnologiainstacron:RCAAP2024-05-22T17:10:53Zoai:run.unl.pt:10362/7501Portal AgregadorONGhttps://www.rcaap.pt/oai/openaireinfo@rcaap.ptopendoar:https://opendoar.ac.uk/repository/71602025-05-28T16:41:55.367942Repositórios Científicos de Acesso Aberto de Portugal (RCAAP) - FCCN, serviços digitais da FCT – Fundação para a Ciência e a Tecnologiafalse
dc.title.none.fl_str_mv Epidemiological characterization, antimicrobial resistance and virulence mechanisms of human and animal streptococci
title Epidemiological characterization, antimicrobial resistance and virulence mechanisms of human and animal streptococci
spellingShingle Epidemiological characterization, antimicrobial resistance and virulence mechanisms of human and animal streptococci
Rato, Márcia Alexandra Gonçalves
Streptococcus agalactiae
Streptococcus dysgalactiae subsp. dysgalactiae
Streptococcus uberis
Molecular typing
Antimicrobial resistance
Virulence
title_short Epidemiological characterization, antimicrobial resistance and virulence mechanisms of human and animal streptococci
title_full Epidemiological characterization, antimicrobial resistance and virulence mechanisms of human and animal streptococci
title_fullStr Epidemiological characterization, antimicrobial resistance and virulence mechanisms of human and animal streptococci
title_full_unstemmed Epidemiological characterization, antimicrobial resistance and virulence mechanisms of human and animal streptococci
title_sort Epidemiological characterization, antimicrobial resistance and virulence mechanisms of human and animal streptococci
author Rato, Márcia Alexandra Gonçalves
author_facet Rato, Márcia Alexandra Gonçalves
author_role author
dc.contributor.none.fl_str_mv Sanches, Ilda
Vilela, Cristina
RUN
dc.contributor.author.fl_str_mv Rato, Márcia Alexandra Gonçalves
dc.subject.por.fl_str_mv Streptococcus agalactiae
Streptococcus dysgalactiae subsp. dysgalactiae
Streptococcus uberis
Molecular typing
Antimicrobial resistance
Virulence
topic Streptococcus agalactiae
Streptococcus dysgalactiae subsp. dysgalactiae
Streptococcus uberis
Molecular typing
Antimicrobial resistance
Virulence
description Dissertação para obtenção do Grau de Doutor em Biologia
publishDate 2011
dc.date.none.fl_str_mv 2011
2011-01-01T00:00:00Z
2012-07-19T09:01:10Z
dc.type.driver.fl_str_mv doctoral thesis
dc.type.status.fl_str_mv info:eu-repo/semantics/publishedVersion
status_str publishedVersion
dc.identifier.uri.fl_str_mv http://hdl.handle.net/10362/7501
TID:101265824
url http://hdl.handle.net/10362/7501
identifier_str_mv TID:101265824
dc.language.iso.fl_str_mv eng
language eng
dc.relation.none.fl_str_mv 978-989-20-2618-3
dc.rights.driver.fl_str_mv info:eu-repo/semantics/openAccess
eu_rights_str_mv openAccess
dc.format.none.fl_str_mv application/pdf
dc.publisher.none.fl_str_mv Faculdade de Ciências e Tecnologia
publisher.none.fl_str_mv Faculdade de Ciências e Tecnologia
dc.source.none.fl_str_mv reponame:Repositórios Científicos de Acesso Aberto de Portugal (RCAAP)
instname:FCCN, serviços digitais da FCT – Fundação para a Ciência e a Tecnologia
instacron:RCAAP
instname_str FCCN, serviços digitais da FCT – Fundação para a Ciência e a Tecnologia
instacron_str RCAAP
institution RCAAP
reponame_str Repositórios Científicos de Acesso Aberto de Portugal (RCAAP)
collection Repositórios Científicos de Acesso Aberto de Portugal (RCAAP)
repository.name.fl_str_mv Repositórios Científicos de Acesso Aberto de Portugal (RCAAP) - FCCN, serviços digitais da FCT – Fundação para a Ciência e a Tecnologia
repository.mail.fl_str_mv info@rcaap.pt
_version_ 1833596121198362624

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