Holistic approaches in the diagnosis, prevention,control and treatment of animal pest and diseases: characterization and production of secondary metabolites from actinomycetes isolated from rare environments against methicillin-resistant Staphylococcus aureus in livestock

Date

2017

Abstract

The Philippines, a biodiversity hotspot in the world, is an excellent source of microbes known to produce novel bioactive compounds. Actinomycetes are one of the most efficient groups in producing these bioactive compounds that have valuable medical, veterinary and agricultural applications. In particular, certain bioactive compounds from Actinomycetes have been found effective against methicillin-resistant Staphylococcus sp. (MRS), which is associated with dairy animals suffering from mastitis. From 39 milk samples collected from cows and goats suffering from mastitis from three dairy farms in CALABARZON [Cavite, Laguna, Batangas, Rizal, Quezon, Philippines], the three presumptive MRS isolates were chosen for this study. On the mannitol salt agar (MSA) with phenol red and 50 ppm oxacillin, the isolates were Gram-positive cocci, exhibited yellow colonies with red coloration and coagulase-negative. Through 16S rRNA sequencing similarity analysis, Isolate C 1225 was putatively identified as Staphylococcus lentus, and C1202 and G20 as Staphylococcus sciuri subspecies sciuri. Using three small Staphylococcus species as test organisms, 19 out of 135 actinomycete isolates from the Philippine soils were found showing antibacterial activity. The actinomycete isolate (S816), which had the most effective antibacterial property as gauged by cup cylinder method, was putatively identified as Streptomyces sp. But the species was not ascertained by 16S rRNA sequence similarity analysis. This isolate had a minimum inhibitory concentration (MIC) value lower than that of vancomycin, the only commercial antibiotic that has remained effective against MRS. Initial ethyl acetate extraction and bioautography assay detected presence of active compounds effective against MRS. A subsequent confirmatory test for methicillin resistance of the putative MRS isolates showed that only Staphylococcus G20 had stable resistance.

Language

English

Document Type

Article

Pages /Collation

51 leaves

En – AGROVOC descriptors

COWS; GOATS; STAPHYLOCOCCUS AUREUS; ACTINOMYCETALES; MASTITIS; ANTIMICROBIAL PROPERTIES; ANIMAL DISEASES; PHILIPPINES

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