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dc.contributor.authorValdezate, Sylvia 
dc.contributor.authorGarrido, Noelia 
dc.contributor.authorCarrasco, Gema 
dc.contributor.authorVillalon-Panzano, Pilar 
dc.contributor.authorMedina-Pascual, Maria Jose 
dc.contributor.authorSaez-Nieto, Juan A
dc.identifier.citationFront Microbiol. 2015 Apr 28;6:376.es_ES
dc.description.abstractThe soil-borne pathogen Nocardia sp. causes severe cutaneous, pulmonary, and central nervous system infections. Against them, co-trimoxazole (SXT) constitutes the mainstay of antimicrobial therapy. However, some Nocardia strains show resistance to SXT, but the underlying genetic basis is unknown. We investigated the presence of genetic resistance determinants and class 1-3 integrons in 76 SXT-resistant Nocardia strains by PCR and sequencing. By E test, these clinical strains showed SXT minimum inhibitory concentrations of ≥32:608 mg/L (ratio of 1:19 for trimethoprim: sulfamethoxazole). They belonged to 12 species, being the main representatives Nocardia farcinica (32%), followed by N. flavorosea (6.5%), N. nova (11.8%), N. carnea (10.5%), N. transvalensis (10.5%), and Nocardia sp. (6.5%). The prevalence of resistance genes in the SXT-resistant strains was as follows: sul1 and sul2 93.4 and 78.9%, respectively, dfrA(S1) 14.7%, blaTEM-1 and blaZ 2.6 and 2.6%, respectively, VIM-2 1.3%, aph(3')-IIIa 40.8%, ermA, ermB, mefA, and msrD 2.6, 77.6, 14.4, and 5.2%, respectively, and tet(O), tet(M), and tet(L) 48.6, 25.0, and 3.9%, respectively. Detected amino acid changes in GyrA were not related to fluoroquinolone resistance, but probably linked to species polymorphism. Class 1 and 3 integrons were found in 93.42 and 56.57% strains, respectively. Class 2 integrons and sul3 genes were not detected. Other mechanisms, different than dfrA(S1), dfrD, dfrF, dfrG, and dfrK, could explain the strong trimethoprim resistance shown by the other 64 strains. For first time, resistance determinants commonly found in clinically important bacteria were detected in Nocardia sp. sul1, sul2, erm(B), and tet(O) were the most prevalent in the SXT-resistant strains. The similarity in their resistome could be due to a common genetic platform, in which these determinants are co-transferred.es_ES
dc.description.sponsorshipThis study was presented at the 54th Interscience Conference on Antimicrobial Agents and Chemotherapy, ICAAC2014, Washington, DC, USA. We thank Adrian Burton for editing and language assistance ( We are very grateful to all persons who took part in this study, and to the sample providers.es_ES
dc.publisherFrontiers Mediaes_ES
dc.relation.isversionofPublisher's versiones_ES
dc.subjectNocardia specieses_ES
dc.subjectantimicrobial resistant determinantses_ES
dc.titleResistance gene pool to co-trimoxazole in non-susceptible Nocardia strainses_ES
dc.rights.licenseAtribución 4.0 Internacional*
dc.identifier.journalFrontiers in microbiologyes_ES
dc.repisalud.centroISCIII::Centro Nacional de Microbiologíaes_ES

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