In vitro selective inhibitory effect of 8-hydroxyquinoline against bifidobacteria and clostridia.

8-Hydroxyquinoline (8HQ) inhibited Clostridium tertium, Clostridium clostridioforme, Clostridium difficile and Clostridium perfringens in vitro with MICs of 8, 16, 32 and 32 µg/mL, respectively. In contrast, MICs of most bifidobacteria (84%) were 512 µg/mL or higher. Thus, 8HQ could be used as anti-clostridial agent or in selective media for bifidobacteria isolation.