Mecanismes de resistència als ß-lactàmics en enterobacteris, 1994-1996

All clinically relevant Enterobacteriaceae strains isolated between 1994 and 1996 without inducible chromosomal b-lactamase, that showed decreased susceptibility to broad-spectrum cephalosporins and/or aztreonam, were selected. The mechanism implicated in the decreased susceptibility was determined...

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Autor: Sabaté Pina, Montserrat
Tipo de recurso: tesis doctoral
Estado:Versión publicada
Fecha de publicación:2002
País:España
Institución:CBUC, CESCA
Repositorio:TDR. Tesis Doctorales en Red
OAI Identifier:oai:www.tdx.cat:10803/3856
Acceso en línea:http://www.tdx.cat/TDX-1107102-132330
http://hdl.handle.net/10803/3856
Access Level:acceso abierto
Palabra clave:Integrons
Enterobactèries
ß-lactàmics
Ciències Experimentals
577
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network_name_str España
repository_id_str
dc.title.none.fl_str_mv Mecanismes de resistència als ß-lactàmics en enterobacteris, 1994-1996
title Mecanismes de resistència als ß-lactàmics en enterobacteris, 1994-1996
spellingShingle Mecanismes de resistència als ß-lactàmics en enterobacteris, 1994-1996
Sabaté Pina, Montserrat
Integrons
Enterobactèries
ß-lactàmics
Ciències Experimentals
577
title_short Mecanismes de resistència als ß-lactàmics en enterobacteris, 1994-1996
title_full Mecanismes de resistència als ß-lactàmics en enterobacteris, 1994-1996
title_fullStr Mecanismes de resistència als ß-lactàmics en enterobacteris, 1994-1996
title_full_unstemmed Mecanismes de resistència als ß-lactàmics en enterobacteris, 1994-1996
title_sort Mecanismes de resistència als ß-lactàmics en enterobacteris, 1994-1996
dc.creator.none.fl_str_mv Sabaté Pina, Montserrat
author Sabaté Pina, Montserrat
author_facet Sabaté Pina, Montserrat
author_role author
dc.contributor.none.fl_str_mv Prats, Guillem, 1942-
Navarro Risueño, Ferran
Universitat Autònoma de Barcelona. Departament de Genètica i de Microbiologia
dc.subject.none.fl_str_mv Integrons
Enterobactèries
ß-lactàmics
Ciències Experimentals
577
topic Integrons
Enterobactèries
ß-lactàmics
Ciències Experimentals
577
description All clinically relevant Enterobacteriaceae strains isolated between 1994 and 1996 without inducible chromosomal b-lactamase, that showed decreased susceptibility to broad-spectrum cephalosporins and/or aztreonam, were selected. The mechanism implicated in the decreased susceptibility was determined by analytical isoelectric focusing, PCR and/or sequenciation. The results obtained showed that the most frequent mechanism implicated in the decreased susceptibility to broad-spectrum cephalosporins and/or aztreonam in E. coli and K. oxytoca was the hyperproduction of the chromosomal b-lactamase, followed by the SHV-1 hyperproduction in E. coli and K. pneumoniae. In our hospital, the incidence of plasmid-mediated extended-spectrum b-lactamases (ESBLs) between 1994 and 1996 was low (0.14%). The b-lactamase that couldn't be identified by the techniques previously described, was characterised by conjugation studies, clonation, and sequenciation experiments, allowing us to describe a new b-lactamase, CTX-M-9, that was the most frequent ESBL detected in our laboratory.<br/> The CTX-M-type b-lactamases has been described in various species of the family Enterobacteriaceae in geographically and temporally widely distant areas, most of them being plasmid-encoded. To know more about the dissemination of these enzymes around the world, we decided to study the environment of blaCTX-M-9. This study suggested us that blaCTX-M-9 is contained in a new complex integron, In60. This integron has the common 5'-CS and 3'-CS conserved sequences of class 1 integron and two gene cassettes encoding for a dihydrofolate reductase (dfrA16) and aminoglycoside-adenylytransferase (aadA2). Downstream of the first sul1 gene is present the orf513. Following this region there is the blaCTX-M-9 and an orf3-like region showing both about 80% identity with blaKLUA-1 and orf3 of K. ascorbata, respectively. Downstream of the orf3-like region, a new insertion sequence designated IS3000, is found. This IS is flanked by two imperfect inverted repeats and its deduced amino acid sequence presents the DD(35)-E motif highly conserved in the transposases. Close to the downstream IS3000 inverted repeat the second 3'-CS, is found. The presence of In60 was evaluated in a total of 37 enterobacteria isolated between 1994 and 1999 carrying a b-lactamase compatible with CTX-M-9. The results obtained showed that 33 strains had the environment compatible with In60 and four strains showed modifications or did not share this environment.
publishDate 2002
dc.date.none.fl_str_mv 2002
2002
2002
2011
dc.type.none.fl_str_mv info:eu-repo/semantics/doctoralThesis
info:eu-repo/semantics/publishedVersion
format doctoralThesis
status_str publishedVersion
dc.identifier.none.fl_str_mv http://www.tdx.cat/TDX-1107102-132330
http://hdl.handle.net/10803/3856
url http://www.tdx.cat/TDX-1107102-132330
http://hdl.handle.net/10803/3856
dc.language.none.fl_str_mv Catalán
language_invalid_str_mv Catalán
dc.rights.none.fl_str_mv info:eu-repo/semantics/openAccess
eu_rights_str_mv openAccess
dc.format.none.fl_str_mv application/pdf
application/pdf
application/pdf
application/pdf
application/pdf
dc.publisher.none.fl_str_mv Universitat Autònoma de Barcelona
publisher.none.fl_str_mv Universitat Autònoma de Barcelona
dc.source.none.fl_str_mv TDX (Tesis Doctorals en Xarxa)
reponame:TDR. Tesis Doctorales en Red
instname:CBUC, CESCA
instname_str CBUC, CESCA
reponame_str TDR. Tesis Doctorales en Red
collection TDR. Tesis Doctorales en Red
repository.name.fl_str_mv
repository.mail.fl_str_mv
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spelling Mecanismes de resistència als ß-lactàmics en enterobacteris, 1994-1996Sabaté Pina, MontserratIntegronsEnterobactèriesß-lactàmicsCiències Experimentals577All clinically relevant Enterobacteriaceae strains isolated between 1994 and 1996 without inducible chromosomal b-lactamase, that showed decreased susceptibility to broad-spectrum cephalosporins and/or aztreonam, were selected. The mechanism implicated in the decreased susceptibility was determined by analytical isoelectric focusing, PCR and/or sequenciation. The results obtained showed that the most frequent mechanism implicated in the decreased susceptibility to broad-spectrum cephalosporins and/or aztreonam in E. coli and K. oxytoca was the hyperproduction of the chromosomal b-lactamase, followed by the SHV-1 hyperproduction in E. coli and K. pneumoniae. In our hospital, the incidence of plasmid-mediated extended-spectrum b-lactamases (ESBLs) between 1994 and 1996 was low (0.14%). The b-lactamase that couldn't be identified by the techniques previously described, was characterised by conjugation studies, clonation, and sequenciation experiments, allowing us to describe a new b-lactamase, CTX-M-9, that was the most frequent ESBL detected in our laboratory.<br/> The CTX-M-type b-lactamases has been described in various species of the family Enterobacteriaceae in geographically and temporally widely distant areas, most of them being plasmid-encoded. To know more about the dissemination of these enzymes around the world, we decided to study the environment of blaCTX-M-9. This study suggested us that blaCTX-M-9 is contained in a new complex integron, In60. This integron has the common 5'-CS and 3'-CS conserved sequences of class 1 integron and two gene cassettes encoding for a dihydrofolate reductase (dfrA16) and aminoglycoside-adenylytransferase (aadA2). Downstream of the first sul1 gene is present the orf513. Following this region there is the blaCTX-M-9 and an orf3-like region showing both about 80% identity with blaKLUA-1 and orf3 of K. ascorbata, respectively. Downstream of the orf3-like region, a new insertion sequence designated IS3000, is found. This IS is flanked by two imperfect inverted repeats and its deduced amino acid sequence presents the DD(35)-E motif highly conserved in the transposases. Close to the downstream IS3000 inverted repeat the second 3'-CS, is found. The presence of In60 was evaluated in a total of 37 enterobacteria isolated between 1994 and 1999 carrying a b-lactamase compatible with CTX-M-9. The results obtained showed that 33 strains had the environment compatible with In60 and four strains showed modifications or did not share this environment.Universitat Autònoma de BarcelonaPrats, Guillem, 1942-Navarro Risueño, FerranUniversitat Autònoma de Barcelona. Departament de Genètica i de Microbiologia2011200220022002info:eu-repo/semantics/doctoralThesisinfo:eu-repo/semantics/publishedVersionapplication/pdfapplication/pdfapplication/pdfapplication/pdfapplication/pdfhttp://www.tdx.cat/TDX-1107102-132330http://hdl.handle.net/10803/3856TDX (Tesis Doctorals en Xarxa)reponame:TDR. Tesis Doctorales en Redinstname:CBUC, CESCACatalánADVERTIMENT. L'accés als continguts d'aquesta tesi doctoral i la seva utilització ha de respectar els drets de la persona autora. Pot ser utilitzada per a consulta o estudi personal, així com en activitats o materials d'investigació i docència en els termes establerts a l'art. 32 del Text Refós de la Llei de Propietat Intel·lectual (RDL 1/1996). Per altres utilitzacions es requereix l'autorització prèvia i expressa de la persona autora. En qualsevol cas, en la utilització dels seus continguts caldrà indicar de forma clara el nom i cognoms de la persona autora i el títol de la tesi doctoral. No s'autoritza la seva reproducció o altres formes d'explotació efectuades amb finalitats de lucre ni la seva comunicació pública des d'un lloc aliè al servei TDX. Tampoc s'autoritza la presentació del seu contingut en una finestra o marc aliè a TDX (framing). Aquesta reserva de drets afecta tant als continguts de la tesi com als seus resums i índexs.info:eu-repo/semantics/openAccessoai:www.tdx.cat:10803/38562026-06-14T12:46:07Z
score 15,301603

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