Evaluation of liquid transport media for the isolation of anaerobic bacteria: Relevance to genital tract specimens

Abstract

A mixture of six known anaerobic bacteria in small numbers was used to develop a simple anaerobic liquid transport system in which fastidious bacteria and oxygen-sensitive anaerobes could remain viable even after 24 hours under anaerobic conditions. The organisms, coated on alginate-wool swabs, were dispersed in pre-reduced tryptone-yeast-glucose medium which acted both as a transport medium and as a diluent for quantitative estimations. The prolonged survival of the bacteria was attributable to the incorporation of laked horse blood or bovine serum in the medium and to the pre-moistening of swabs with these blood products. At concentrations not greater than three to five per cent they acted as protective agents, enabling complete or almost complete recovery of all the bacteria to be made, even the extremely oxygen-sensitive anaerobic Clostridium novyi B. However, the largest number of obligate anaerobic bacterial species was isolated from the urethra of patients with non-gonococcal urethritis when the redox potential of the medium was further reduced with titanium trichloride.