Artículo
Subinhibitory concentrations of penicillin increase the mutation rate to optochin resistance in Streptococcus pneumoniae
Cortes, Paulo R.; Piñas, German Eduardo
; Albarracín Orio, Andrea Georgina
; Echenique, Jose Ricardo
Fecha de publicación:
11/2008
Editorial:
Oxford University Press
Revista:
Journal of Antimicrobial Chemotherapy
ISSN:
0305-7453
Idioma:
Inglés
Tipo de recurso:
Artículo publicado
Clasificación temática:
Resumen
Objectives: The aim of this work was to study the effect of subinhibitory concentrations of penicillin, chloramphenicol and erythromycin on the mutation rate of Streptococcus pneumoniae. Methods: The mutation rate to rifampicin and optochin resistance was estimated using fluctuation analysis in three capsulated S. pneumoniae strains, cultured both with and without different subinhibitory antibiotic concentrations. The atpAC and rpoB mutations that conferred optochin and rifampicin resistance, respectively, were identified by DNA sequencing. Results: The exposure to subinhibitory concentrations of penicillin increased the mutation rate (expressed as mutation per cell division) to optochin resistance between 2.1- and 3.1-fold for all three strains studied. In contrast, the rifampicin resistance assay showed no significant variations. To analyse the putative cause of the different responses between the optochin and rifampicin tests, mutations that conferred resistance in both cases were analysed. The difference may be explained by the genetic nature of the atpAC mutations, mostly transversions, which are not efficiently repaired by the HexAB mismatch repair system. Conclusions: We demonstrated that subinhibitory concentrations of penicillin significantly increased the mutation rate of S. pneumoniae, suggesting that exposure to this antibiotic could help this pathogen to acquire mutations that confer resistance to other antibiotics. The optochin test was useful to detect this phenomenon and it should be considered for further mutability analysis in S. pneumoniae.
Palabras clave:
STREPTOCOCCUS PNEUMONIAE
,
OPTOCHIN
,
MUTATION RATE
,
ANTIBIOTIC RESISTANCE
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Identificadores
Colecciones
Articulos(CCT - CORDOBA)
Articulos de CTRO.CIENTIFICO TECNOL.CONICET - CORDOBA
Articulos de CTRO.CIENTIFICO TECNOL.CONICET - CORDOBA
Articulos(CIBICI)
Articulos de CENTRO DE INV.EN BIOQUI.CLINICA E INMUNOLOGIA
Articulos de CENTRO DE INV.EN BIOQUI.CLINICA E INMUNOLOGIA
Citación
Cortes, Paulo R.; Piñas, German Eduardo; Albarracín Orio, Andrea Georgina; Echenique, Jose Ricardo; Subinhibitory concentrations of penicillin increase the mutation rate to optochin resistance in Streptococcus pneumoniae; Oxford University Press; Journal of Antimicrobial Chemotherapy; 62; 5; 11-2008; 973-977
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