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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

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

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Author(s):
Tomazi, Tiago [1] ; de Souza Filho, Antonio Francisco [2] ; Heinemann, Marcos Bryan [2] ; dos Santos, Marcos Veiga [1]
Total Authors: 4
Affiliation:
[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
Total Affiliations: 2
Document type: Journal article
Source: PLoS One; v. 13, n. 6 JUN 21 2018.
Web of Science Citations: 2
Abstract

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)

FAPESP's process: 13/22286-3 - Profile of etiologic agents causing clinical mastitis and antimicrobial use in dairy herds
Grantee:Tiago Tomazi
Support Opportunities: Scholarships in Brazil - Doctorate
FAPESP's process: 14/17411-6 - Economic impact and profile of etiologic agents of bovine mastitis
Grantee:Marcos Veiga dos Santos
Support Opportunities: Regular Research Grants
FAPESP's process: 15/10332-6 - Study of the molecular diversity of strains of Staphylococcus aureus isolated from bovine mastitis
Grantee:Marcos Bryan Heinemann
Support Opportunities: Regular Research Grants