Author:
Girardini Lilian K., ,Paim Daniel S.,Ausani Thais C.,Lopes Graciela V.,Pellegrini Debora C.P.,Brito Maria Aparecida V.P.,Cardoso Marisa, , ,
Abstract
ABSTRACT: In intensive dairy farming, persistent intramammary infection has been associated with specific Staphylococcus (S.) aureus strains, and these strains may be resistant to antimicrobials. The objective of this study was to evaluate the antimicrobial resistance phenotypes of S. aureus isolates and to assess the distribution and the persistence of clonal groups in small dairy herds of southern Brazil. Milk samples were collected from all lactating cows from 21 dairy farms over a two-year period, totaling 1,060 samples. S. aureus isolates were tested for susceptibility to thirteen antimicrobials using the disk diffusion method. The total DNA of the isolates was subjected to SmaI digestion followed by pulsed-field gel electrophoresis (PFGE). Banding patterns differing by ≤4 bands were considered members of a single PFGE cluster. The frequency of S. aureus isolation ranged from 3.45% to 70.59% among the 17 S. aureus-positive herds. Most S. aureus isolates (87.1%) were susceptible to all antimicrobials; resistance to penicillin (18.2%) was the most frequently observed. The 122 isolates subjected to macrorestriction analysis were classified into 30 PFGE-clusters. Among them, only 10 clusters were intermittent or persistent over the two-year period. The majority (93.6%) of isolates belonging to persistent and intermittent clusters were susceptible to all tested antimicrobials. S. aureus intramammary colonization in small dairy farms of southern Brazil is most frequently caused by sporadic PFGE clusters, although some persistent clusters can arise over time. Both sporadic and persistent isolates were highly susceptible to antimicrobials.
Reference38 articles.
1. A comparative study of Staphylococcus aureus strains isolated from bovine subclinical mastitis during 1952-1956 and 1992;Aarestrup F.M.;Acta Vet. Scand.,1995
2. Prevalence and duration of intramammary infection in Danish heifers during the peripartum period;Aarestrup F.M.;J. Dairy Sci.,1997
3. Risk factors associated with the antimicrobial resistance of Staphylococcus aureus isolated from bovine mastitis;Beuron D.C.;Pesq. Vet. Bras.,2014
4. Concentração mínima inibitória de dez antimicrobianos para amostras de Staphylococcus aureus isoladas de infecção intramamária bovina;Brito M.A.V.P.;Arq. Bras. Med. Vet. Zootec.,2001
5. Genotypic analysis of Staphylococcus aureus from milk of dairy cows with mastitis in Argentina;Buzzola F.R.;Epidemiol. Infect.,2001
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