Toxin production by Clostridium difficile in a defined medium with limited amino acids.
Basal defined medium (BDM) containing vitamins, minerals and seven amino acids--(/L) tryptophan 0.1 g, methionine 0.2 g, valine 0.3 g, isoleucine 0.3 g, proline 0.3 g, leucine 0.4 g and cysteine 0.5 g--which appeared to be essential for good growth of Clostridium difficile was prepared. Addition of glycine 0.2 g/L and threonine 0.4 g/L to BDM produced better growth of strain VPI 10463, and this defined medium was designated minimum amino acid-defined medium (MADM). Production of toxins A and B by strain VPI 10463 in 6 x MADM containing (/L) tryptophan 0.6 g, methionine 1.2 g, valine 1.8 g, isoleucine 1.8 g, proline 1.8 g, leucine 2.4 g, cysteine 0.5 g, glycine 0.2 g and threonine 0.4 g, was much greater than in MADM. Toxin production by 20 C. difficile strains was examined in two defined media--6 x MADM and complete amino acid-defined medium (CADM) containing 18 amino acids--and one complex medium, modified brain heart infusion medium (m-BHI). Simultaneous production of toxins A and B by all test strains was demonstrated in m-BHI and the two defined media. It was also shown that 6 x MADM was generally better than CADM and as effective as m-BHI for stimulating toxin production by 13 strains. This defined medium would be useful for studies on the physiology, metabolism and pathogenicity of C. difficile.
Department of Bacteriology, School of Medicine, Kanazawa University, Ishikawa, Japan.
K
K
Yamakawa
S
S
Kamiya
X Q
XQ
Meng
T
T
Karasawa
S
S
Nakamura
D000596:Amino Acids / Q000378:metabolism; D001426:Bacterial Proteins; D001427:Bacterial Toxins / Q000096:biosynthesis*; D016360:Clostridioides difficile / Q000254:growth & development / Q000378:metabolism*; D003470:Culture Media; D003603:Cytotoxins / Q000096:biosynthesis*; D004768:Enterotoxins / Q000096:biosynthesis*; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans
D000596:Amino Acids; D001426:Bacterial Proteins; D001427:Bacterial Toxins; D003470:Culture Media; D003603:Cytotoxins; D004768:Enterotoxins; C041348:tcdA protein, Clostridium difficile; C031815:toxB protein, Clostridium difficile