The Influence of Carbon Dioxide on the Growth of Obligate and Facultative Anaerobes on Solid Media

Abstract

SUMMARY The quantitative recovery of test strains of bacteria on blood agar media was compared in Baird and Tatlock anaerobic jars with and without additional CO2 in the gas mixture. Both the colony size and the colony count of Gramnegative anaerobes and some of the test strains of clostridia were increased in the presence of added CO2. An enhancing effect was also noted with two strains of haemolytic streptococci. The addition of 10 per cent. CO2 as a part of routine anaerobic procedure is recommended for the diagnostic service laboratory.