Molecular characterization and antimicrobial susceptibility pattern of Streptococcus agalactiae isolated from clinical mastitis in dairy cattle

Autor(es)

Tomazi, Tiago ^[1] ; de Souza Filho, Antonio Francisco ^[2] ; Heinemann, Marcos Bryan ^[2] ; dos Santos, Marcos Veiga ^[1]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Dept Anim Prod & Nutr, Milk Qual Res Lab Qualileite, Pirassununga - Brazil

^[2] Univ Sao Paulo, Dept Prevent Vet Med & Anim Hlth, Lab Bacterial Zoonosis, Sao Paulo - Brazil

• Tipo de documento: Artigo Científico
• Fonte: PLoS One; v. 13, n. 6 JUN 21 2018.
• Citações Web of Science: 2

Resumo

The objectives of this study were to: (a) genotypically characterize Streptococcus agalactiae isolates recovered from clinical mastitis (CM) cases in dairy cows and, (b) determine the association of antimicrobial susceptibility (AMS) and genotypes of Strep. agalactiae clustered according to the genetic similarity. A total of 89 Strep. agalactiae isolates recovered from bovine CM were genotyped using random amplified polymorphic DNA (RAPD) analysis. In addition, the AMS of the isolates was determined using a commercial broth microdilution test composed of 10 antimicrobials (penicillin, ampicillin, oxacillin, cephalothin, ceftiofur, penicillin/novobiocin, erythromycin, pirlimycin, tetracycline, and sulfadimethoxine). Descriptive analysis was used to report the frequency of RAPD-types and genotypic clusters within herd, housing system, season and CM severity scores. The minimal antimicrobial concentrations that inhibited 50% (MIC50) and 90% (MIC90) of the isolates were calculated and survival analysis was completed to verify the differences of AMS among genotypic clusters. Results of RAPD showed a great genotypic diversity of Strep. agalactiae (45 RAPD-types) and three clusters (Ia, Ib and II) were created based on the genetic similarity among genotypes. After clustering, a high genetic similarity was observed within and between herds. Overall, Strep. agalactiae showed high susceptibility to most antimicrobials, except to tetracycline and erythromycin. Differences in the AMS among clusters were observed for ampicillin, ceftiofur, erythromycin, pirlimycin, sulfadimethoxine and tetracycline. In conclusion, Strep. agalactiae is still highly susceptible to most antimicrobials, although differences in susceptibility to certain antimicrobials were observed among genotypic clusters. (AU)

• Processo FAPESP: 13/22286-3 - Perfil de agentes etiológicos causadores de mastite clínica e uso de antimicrobianos em rebanhos leiteiros
• Beneficiário: Tiago Tomazi
• Modalidade de apoio: Bolsas no Brasil - Doutorado
• Processo FAPESP: 14/17411-6 - Impacto econômico e perfil de agentes etiológicos da mastite bovina
• Beneficiário: Marcos Veiga dos Santos
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 15/10332-6 - Estudo da diversidade molecular de linhagens de Staphylococcus aureus isolados de mastite bovina
• Beneficiário: Marcos Bryan Heinemann
• Modalidade de apoio: Auxílio à Pesquisa - Regular