NUTRITION OF FIVE BACTEROIDES STRAINS

Abstract

Some of the nutritional requirements of five gram-negative anaerobic bacilli including Ristella perfoetens, Zuberella clostridiformis and three Bacteroides strains freshly isolated from clinical exudates were investigated. A fluid maintenance medium was developed in which the three freshly isolated strains C-4, C-7 and C-2795 grew maximally in 12 to 24 hr. The maintenance medium contained 2.0% Trypticase and Proteose Peptone, 0.5% glucose and 0.1% sodium thioglycolate; it was adjusted to pH 7.2 and supplemented with 0.1 [mu]g of hemin/ml. Strains C-4, C-7 and C-2795 were cultivated through 14 serial cultures in fluid maintenance medium containing 0.1 [mu]g of hemin/ml. The most satisfactory inoculum was a 1:100 or 1:1,000 dilution of a 24-hr. seed culture. All the strains except Z. clostridiformis grew serially in a defined medium. R. perfoetens required pantothenic acid, nicotinic acid and the following amino acids: histidine, tryptophan, tyrosine, valine, phenylalanine, cystine and probably arginine, glutamic acid, methionine, glycine, isoleucine, leucine and lysine. The C-4, C-7 and C-2795 strains required the hemin supplement in defined medium but not vitamins, purines or pyrimidines.