The Effect of Media Selection on the Membrane Characteristics and Fatty Acid Composition of Staphylococcus Aureus

摘要

The cellular membrane is a vital structure to a microorganism and impacts important aspects of environmental regulation and growth. The physical structure of cellular membranes plays a key role in bacterial growth at low temperatures, membrane permeability and susceptibility to membrane active molecules as well as broader aspects of bacterial physiology and pathogenesis. Mueller Hinton medium is the required medium for antimicrobial susceptibility testing in the US, but there are many other types of media used in staphylococcal research. Different media vary in their nutrient compositions, and the effect of media composition on bacterial physiology is incompletely understood. The aim of this study is to elucidate possible mechanisms underlying alterations to important membrane characteristics of Staphylococcus aureus when grown in different nutrient media. The characteristics of interest in this study are fatty acid composition, membrane fluidity and carotenoid content of the cellular membrane. Each of these characteristics plays an important role in S. aureus growth, virulence and resistance to antibiotics. S. aureus cells of different strains will be grown on a number of media types and their membrane characteristics investigated using previously tested methodologies. Changes in bacterial physiology attributed to media selection could cause a rethinking of which types of media are used for antimicrobial susceptibility testing as well as other important experimental procedures.