Evaluation of Adding Erythritol to Farrell Medium for Primary Isolation of the Brucella melitensis Strains

Abstract

This study aims to evaluate the addition of erythritol to Farrell medium (FM) for the primary isolation of B.melitensis strains. Selective media, particularly FM, is commonly used for Brucella isolation. Isolation is the gold standard for the diagnosis of brucellosis. The isolation success of selective media depends on their ingredients. Isolation rate may decrease particularly in contaminated samples; therefore, the addition of components like erythritol that augments the growth of Brucella species on media can support isolation. In this study, organ samples associated with 14 small ruminant abortion cases caused by B.melitensis strains were utilized. Organ suspensions were inoculated to FM and Farrel medium with erythritol (F+ER) simultaneously. The media’s isolation and inhibition performance was observed during incubation. The addition of erythritol was evaluated based on whether it provides earlier isolation with the help of increasing the colony growth rate and colony size. According to the findings, F+ER is more advantageous for 12 samples among 14 through isolation as it enables faster colony growth and larger colonies. The results confirm the recommendation of adding erythritol particularly in the samples with inadequate contaminant inhibition. Therefore, high isolation performance can be achieved through erythritol addition to the selective media like FM.