Link between genotype and antimicrobial resistance in bovine mastitis-related Staphylococcus aureus strains, determined by comparing Swiss and French isolates from the Rhône Valley.

Staphylococcus aureus is a major bovine mastitis pathogen. Although the reported antimicrobial resistance was generally low, the emergence of new genetic clusters in bovine mastitis requires examination of the link between antimicrobial resistance and genotypes. Here, amplified fragment length polymorphism (AFLP) profiles and standard antimicrobial resistance profiles were determined in order to characterize a total of 343 S. aureus cow mastitis isolates from two geographically close regions of Switzerland and France. AFLP profiles revealed similar population compositions in the two regions, with 4 major clusters (C8, C20, C97, and C151), but the proportions of isolates in each cluster significantly diverged between the two countries (P = 9.2 × 10⁻⁹). Antimicrobial resistance was overall low (< 5% resistance to all therapeutically relevant molecules), with the exception of penicillin resistance, which was detected in 26% of the isolates. Penicillin resistance proportions differed between clusters, with only 1 to 2% of resistance associated with C20 and C151 and up to 70% associated with bovine C97. The prevalence of C20 and C8 was unexpectedly high and requires further investigation into the mechanism of adaptation to the bovine host. The strong association of penicillin resistance with few clusters highlights the fact that the knowledge of local epidemiology is essential for rational choices of antimicrobial treatment in the absence of susceptibility testing. Taken together, these observations argue in favor of more routine scrutiny of antimicrobial resistance and antibiotic-resistant clones in cattle and the farm environment.

[Lettre autographe signée de G. Dejean adressée à Escudier, 22 février 1859]

En français

Targeted Small Business Link, March 2010, Vol. 3, no. 1

Targeted Small Business News from the Business Development Division of the Iowa Department of Economic Development

Report on a special investigation of Oran Township in Fayette County for the period January 1, 2003 through September 22, 2009

Report on a special investigation of Oran Township in Fayette County for the period January 1, 2003 through September 22, 2009

[Lettre autographe signée de Giuseppe Verdi à Madame Escudier, Paris, 22 septembre 1866]

Comprend aussi une enveloppe

[Lettre autographe signée de Giuseppe Verdi à Escudier, Gênes, 22 janvier 1869]

Comprend aussi une enveloppe