Antimicrobial activity of crude extracts from actinomycetes against mastitis pathogens

Autor(es)

Leite, R. F. ^[1] ; Goncalves, J. L. ^[1] ; Peti, A. P. F. ^[2] ; Figueiro, F. S. ^[2] ; Moraes, L. A. B. ^[2] ; Santos, V, M.

Afiliação do(s) autor(es)

^[1] V, Univ Sao Paulo, Dept Anim Sci, Sch Vet Med & Anim Sci, BR-13635900 Pirassununga, SP - Brazil

^[2] Univ Sao Paulo, Dept Chem, BR-14040901 Ribeirao Preto, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: JOURNAL OF DAIRY SCIENCE; v. 101, n. 11, p. 10116-10125, NOV 2018.
• Citações Web of Science: 1

Resumo

The emergence of antimicrobial resistance to commonly used antibiotics has necessitated the development of new antimicrobial products. Crude extracts produced by actinomycetes contain antimicrobial metabolites that can inhibit bacterial growth. The objective of our study was to evaluate the antimicrobial activity of crude extracts (Caat1-54 and CaatP5-8) produced by actinomycetes against isolates of Staphylococcus aureus, Staphylococcus chromogenes, Streptococcus dysgalactiae, and Streptococcus uberis, which were obtained from the milk of cows affected by mastitis in 23 dairy herds. Twenty isolates of each bacterial species were used to define minimum inhibitory concentrations (MIC) of both crude extracts and ceftiofur (positive control). The MIC50 and MIC90 were defined at the concentration required to inhibit the growth of 50 and 90% of bacterial isolates tested, respectively. The MIC results were evaluated by survival analysis. Staphylococcus aureus isolates presented MIC90 of Caat 1-54 >= 6.25 mu g/mL, ceftiofur >= 12.5 mu g/mL, and Caat P5-8 >= 100 mu g/mL. Streptococcus uberis presented MIC90 of ceftiofur >= 0.39 mu g/mL, Caat 1-54 >= 50 mu g/mL, and Caat P5-8 >= 100 mu g/mL. Staphylococcus chromogenes isolated from subclinical mastitis presented MIC90 of Caat 1-54 >= 0.78 mu g/mL and ceftiofur and Caat P5-8 of >= 6.25 and >= 100 mu g/mL, respectively. Streptococcus dysgalactiae isolated from clinical mastitis presented similar MIC90 values between antimicrobials tested (ceftiofur, Caat 1-54, and Caat P-58), but these values (>= 100 mu g/mL) were higher than the values obtained from other pathogens evaluated in the present study. Our results indicate that Caat 1-54 and Caat P5-8 crude extracts present in vitro antimicrobial activity against isolates of Staph. aureus, Staph. chromogenes, Strep. dysgalactiae, and Strep. uberis isolated from clinical and subclinical mastitis. (AU)

• Processo FAPESP: 16/22023-0 - Ativação de Genes Crípticos em Actinobactérias Através da Indução de Resistência a Antibióticos
• Beneficiário: Luiz Alberto Beraldo de Moraes
• Modalidade de apoio: Auxílio à Pesquisa - Regular