GROWTH REQUIREMENTS OF HAEMOPHILUS VAGINALIS

A medium, composed of peptone, maltose, dextrose and phosphate buffer, which supports good growth of Haemophilus vaginalis has been devised. Growth was about equally good with soluble starch substituted for maltose. Optimal growth occurred in the media adjusted to pH 6.8 before sterilization and the media sterilized at 112 C for 12 minutes supported better growth than did corresponding media sterilized at 121 C for 15 minutes. The organisms grew both aerobically and anaerobically. For growth in a semi-defined medium, containing enzymatically hydrolyzed vitamin-free casein, inorganic salts, carbohydrates and six purine and pyrimidine bases, the organisms were found to require the following B-vitamins: thiamine · HCl, riboflavin, niacin (or niacinamide), pteroylglutamic acid, and biotin. They failed to grow in the above medium lacking purine and pyrimidine bases, but the single omission of any one of the six bases (adenine sulfate, guanine·HCl, cytosine, uracil, thymine, and xanthine) except adenine sulfate did not affect growth of either strain tested. One strain failed to grow in the medium lacking adenine sulfate. Since the strains investigated, including the type, do not require X and/or V factors or otherwise definable coenzymelike substances, they do not qualify as members of the genus Haemophilus on the basis of its current circumscription. Thus, reconsideration must be given to the classification of the organisms now known as Haemophilus vaginalis. © 1969 Swets & Zeitlinger.