M. Stoltenberg et al., Histochemical tracing of bismuth in Helicobacter pylori after in vitro exposure to bismuth citrate, SC J GASTR, 36(2), 2001, pp. 144-148
Background: Bismuth-containing drugs are widely used in the treatment of He
licobacter pylori associated peptic ulcer. The mechanism of action of bismu
th salts is, however not fully understood, and at present no histochemical
techniques for the demonstration of bismuth salts is, are available. The ai
ms were to present a histochemical method for the detection of bismuth in H
. pylori and to demonstrate bismuth uptake in H. pylori after in vitro expo
sure to bismuth citrate. Methods: H. pylori cultures (the strain used in th
is study was CCUG 17874), were exposed to bismuth citrate at different conc
entrations (0, 4.6, 80. 200 muM) and for different lengths of time (0 min,
15 min. 1 h, 24 h, 48 h). The samples were fixed in glutaraldehyde, centrif
uged, and exposed to autometallographic (AMG) development in order to detec
t bismuth histochemically. Results: A detailed protocol on the AMG bismuth
technique on H. pylori exposed to bismuth in vitro is given. This method re
sults in easily detectable AMG grains of silver enhanced bismuth particles
at the electron microscopical level, and shows that bismuth accumulates. in
ii. pylori, predominantly near the wall of the bacteria. Bismuth uptake is
followed by bacterial degeneration. Conclusion: The present technique with
its ability to trace bismuth constitutes a valuable tool in the efforts of
clarifying the mechanism of action of bismuth on H. pylori, and supports t
he notion that bismuth has an antimicrobial activity in itself.