The impact of intestinal microflora on serum bilirubin levels.
OBJECTIVE
Intestinal microflora plays an important role in the pathogenesis of neonatal jaundice by inhibiting enterosystemic circulation of bilirubin. The present study aimed to investigate the influence of intestinal microflora on serum bilirubin levels in hyperbilirubinemic Gunn rats.


METHODS
After a baseline phase Gunn rats received oral antibiotics (either clindamycin/neomycine or co-trimethoxazole for four days, phase II). Intestinal colonization was carried out either with a bilirubin-reducing strain of C. perfringens or C. pasteurianum incapable of reducing bilirubin (phase III). Serum bilirubin and fecal bile pigments were determined at the end of each phase.


RESULTS
Oral administration of clindamycin/neomycine resulted in the disappearance of fecal urobilinoids. Simultaneously, serum bilirubin increased dramatically (186+/-31 vs. 289+/-35 micromol/l, P=0.004). Intestinal colonization with C. perfringens led to reappearance of fecal urobilinoid production accompanied with a partial decrease of serum bilirubin (289+/-35 vs. 239+/-17 micromol/l, P=0.013), whereas the effect of C. pasteurianum on bile pigment metabolism was negligible. Co-trimethoxazole therapy had no effect on serum and intestinal metabolism of bilirubin.


CONCLUSIONS
Intestinal microflora greatly affects intravascular metabolism of bilirubin. Prolonged use of certain antibiotics in man may lead to an increase in serum bilirubin levels, while the enhancement of intestinal catabolism may have an opposite effect.
Vítek
Libor
L
Institute of Clinical Biochemistry and Laboratory Diagnostics, 1st Medical Faculty, Charles University of Prague, U Nemocnice 2, Praha 2, 128-08 Prague, Czech Republic. vitek@cesnet.cz
Zelenka
Jaroslav
J
Zadinová
Marie
M
Malina
Jirí
J
D000818:Animals; D001663:Bilirubin / Q000032:analysis / Q000097:blood*; D003016:Clostridium perfringens / Q000502:physiology*; D005243:Feces / Q000737:chemistry; D014453:Glucuronosyltransferase / Q000172:deficiency; D006801:Humans; D007231:Infant, Newborn; D007422:Intestines / Q000382:microbiology*; D007567:Jaundice, Neonatal / Q000382:microbiology / Q000503:physiopathology; D008297:Male; D051381:Rats; D011911:Rats, Gunn
D014453:Glucuronosyltransferase; D001663:Bilirubin