Methodology for Integral Study of Antagonistic Activity of Normal Nasal Microbiota to Select Potential Probiotics Efficient in Eradication of Staphylococcus aureus.

The aim of this study was the development of a methodology for the integral study of the antagonistic activity of normal human microbiota against Staphylococcus aureus to enable direct selection (without prior isolation of pure cultures) of potentially highly efficient probiotic preparations. The selection of bacterial representatives of normal human nasal microbiota capable of antagonizing S. aureus was carried out using two complimentary methods: replica-plating and deferred antagonism procedures. The material of the anterior nares from healthy human subjects was plated onto the surface of different nutrient media agar plates followed by incubation under appropriate conditions. The grown bacterial colonies were replica-plated to Petri dishes with nutrient agar overlayed with a thin layer of a soft agar which contained the culture of an indicator S. aureus strain. This agar also supported the growth of potential probiotic strains. The potential probiotic strains were selected by their ability to suppress the growth of S. aureus around their colonies. Most active strains-inhibitors may be used to develop probiotic preparations with targeted activity against S. aureus.