Production of toxins A and B by Clostridium difficile is enhanced in a defined medium with biotin-limited conditions. In the present study compounds inhibitory to enhanced toxin production by a C. difficile strain were examined. Increases in biotin concentration from 0.05 nM to 50 nM accelerated growth and inhibited enhanced toxin production. Asparagine, glutamic acid and glutamine (10 mM) showed an effect on growth and toxin production similar to that of biotin. Lysine (10 mM) suppressed growth and inhibited toxin production. Addition of these toxin-inhibitory compounds within an incubation period of 2 days inhibited the enhanced toxin production, but later addition showed only slight inhibition of toxin production. Amino acids contained in the defined medium under the biotin-limited conditions were actively utilised in the presence of the three toxin-inhibitory amino acids, but in the presence of lysine, amino-acid utilisation was suppressed. Different mechanisms of action of these toxin-inhibitory molecules, which may be divided into excess biotin, asparagine-glutamic acid-glutamine group, and lysine, are discussed.
JohnsonJ. L.,
PhelpsC.,
BarrosoL.,
RobertsM. D.,
LyerlyD. M.,
WilkinsT. D. Cloning and expression of the toxin B gene of Clostridium difficile. Curr Microbiol1990; 20:397–401
JustI.,
SelzerJ.,
WilmM.,
von Eichel-StreiberC.,
MannM.,
AktoriesK. Glucosylation of Rho proteins by Clostridium difficile toxin B. Nature1995; 375:500–503
YamakawaK.,
KarasawaT.,
IkomaS.,
NakamuraS. Enhancement of Clostridium difficile toxin production in biotin-limited conditions. J Med Microbiol1996; 44:111–114
YamakawaK.,
KamiyaS.,
MengX. Q.,
KarasawaT.,
NakamuraS. Toxin production by Clostridium difficile in a defined medium with limited amino acids. J Med Microbiol1994; 41:319–323
HaslamS. C.,
KetleyJ. M.,
MitchellT. J.,
StephenJ.,
BurdonD. W.,
CandyD. C. A. Growth of Clostridium difficile and production of toxins A and B in complex and defined media. J Med Microbiol1986; 21:293–297
KamiyaS.,
OguraH.,
MengX. Q.,
NakamuraS. Correlation between cytotoxin production and sporulation in Clostridium difficile. J Med Microbiol1992; 37:206–210
Patterson-CurtisS. I.,
JohnsonE. A. Regulation of neurotoxin and protease formation in Clostridium botulinum Okra B and Hall A by arginine. Appl Environ Microbiol1989; 55:1544–1548
AndreesenJ. R.,
BahlH.,
GottschalkG. Introduction to the physiology and biochemistry of the genus Clostridium. In
MintonN. P.,
ClarkeD. J.
(eds) Clostridia New York: Plenum Press; 198927–62
BraunV.,
HundsbergerT.,
LeukelP.,
SouerbomM.,
von Eichel-StreiberC. Definition of the single integration site of the pathogenicity locus in Clostridium difficile. Gene1996; 181:29–38
HundsbergerT.,
BraunY.,
WeidmannM.,
LeukelP.,
SauerbomM.,
von Eichel-StreiberC. Transcription analysis of the genes tcdA –E of the pathogenicity locus of Clostridium difficile. Eur J Biochem1997; 244:735–742