New selective media for isolation of clostridia from faecal specimens

Abstract

Two selective media, novobiocin‐colistin agar (NCA) and colistin‐crystal violet agar (CCA), were developed for isolating clostridia from human and animal faeces. The basal medium was modified Eggerth‐Gagnon agar. The NCA medium contains novobiocin (8 μg ml‐1) and colistin (8 μg ml‐1) and the CCA medium contains colistin (10 μg ml‐1) and crystal violet (10 μg ml‐1). Nine faecal specimens were cultured. Clostridia isolated on these media were similar to those on non‐selective media, and higher than those isolated after heat treatment. However, more clostridial species were isolated on the new selective media compared with the non‐selective medium. These selective agars were particularly useful for enumerating and isolating clostridia from human faeces. Copyright © 1995, Wiley Blackwell. All rights reserved