Impact of three ampicillin dosage regimens on selection of ampicillin resistance in Enterobacteriaceae and excretion of blaTEM genes in swine feces. - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Applied and Environmental Microbiology Année : 2007

Impact of three ampicillin dosage regimens on selection of ampicillin resistance in Enterobacteriaceae and excretion of blaTEM genes in swine feces.

Résumé

The aim of this study was to assess the impact of three ampicillin dosage regimens on ampicillin resistance among Enterobacteriaceae recovered from swine feces by use of phenotypic and genotypic approaches. Phenotypically, ampicillin resistance was determined from the percentage of resistant Enterobacteriaceae and MICs of Escherichia coli isolates. The pool of ampicillin resistance genes was also monitored by quantification of bla(TEM) genes, which code for the most frequently produced beta-lactamases in gram-negative bacteria, using a newly developed real-time PCR assay. Ampicillin was administered intramuscularly and orally to fed or fasted pigs for 7 days at 20 mg/kg of body weight. The average percentage of resistant Enterobacteriaceae before treatment was between 2.5% and 12%, and bla(TEM) gene quantities were below 10(7) copies/g of feces. By days 4 and 7, the percentage of resistant Enterobacteriaceae exceeded 50% in all treated groups, with some highly resistant strains (MIC of >256 microg/ml). In the control group, bla(TEM) gene quantities fluctuated between 10(4) and 10(6) copies/g of feces, whereas they fluctuated between 10(6) to 10(8) and 10(7) to 10(9) copies/g of feces for the intramuscular and oral routes, respectively. Whereas phenotypic evaluations did not discriminate among the three ampicillin dosage regimens, bla(TEM) gene quantification was able to differentiate between the effects of two routes of ampicillin administration. Our results suggest that fecal bla(TEM) gene quantification provides a sensitive tool to evaluate the impact of ampicillin administration on the selection of ampicillin resistance in the digestive microflora and its dissemination in the environment.
Fichier principal
Vignette du fichier
Bibbal_Authors_manuscript_AEM_2007.pdf (133 Ko) Télécharger le fichier
Origine : Fichiers produits par l'(les) auteur(s)
Loading...

Dates et versions

hal-00517560 , version 1 (16-09-2010)

Identifiants

Citer

Delphine Bibbal, Véronique Dupouy-Guiraute, Jean-Pierre Ferré, Pierre-Louis Toutain, Olivier Fayet, et al.. Impact of three ampicillin dosage regimens on selection of ampicillin resistance in Enterobacteriaceae and excretion of blaTEM genes in swine feces.. Applied and Environmental Microbiology, 2007, 73 (15), pp.4785-90. ⟨10.1128/AEM.00252-07⟩. ⟨hal-00517560⟩
185 Consultations
423 Téléchargements

Altmetric

Partager

Gmail Facebook X LinkedIn More