• We are sorry, but NCBI web applications do not support your browser and may not function properly. More information
Logo of aacPermissionsJournals.ASM.orgJournalAAC ArticleJournal InfoAuthorsReviewers
Antimicrob Agents Chemother. May 1997; 41(5): 1064–1068.
PMCID: PMC163851

Pentostam induces resistance to antimony and the preservative chlorocresol in Leishmania donovani promastigotes and axenically grown amastigotes.


An axenic amastigote culture system was utilized to directly assess the stage-specific antileishmanial effects of antimony on amastigotes of Leishmania donovani devoid of the macrophage host cell. Pentostam, which contains antimony in the form of sodium stibogluconate and the preservative chlorocresol, was used. Cell density was quantified by measuring the activity of the stable enzyme ornithine decarboxylase. Dose-response curve analyses show that Leishmania promastigotes are susceptible to Pentostam, with the 50% inhibitory concentration (IC50) being 104 microg/ml, while amastigotes are more susceptible, with the IC50 being 24 microg/ml. Promastigotes and amastigotes are also susceptible to chlorocresol, with IC50s being 1.27 and 1.82 microg/ml, respectively. Given that promastigotes are insensitive to antimony, these results suggest that the increased susceptibility of amastigotes to Pentostam is due to the stage-specific activity of sodium stibogluconate. To further study this phenomenon, spontaneous resistance to Pentostam was induced in L. donovani promastigotes by increasing the concentration of Pentostam in the growth medium in a stepwise fashion. Two mutants, Ld1S.04 and Ld1S.20, grew at 0.4 and 2.0 mg of Pentostam per ml, respectively. Promastigotes of these mutants were 11 and 21 times, respectively, more resistant to Pentostam than the wild type. Amastigotes were 40 and 148 times, respectively, more resistant than the wild type. The mutants were also chlorocresol resistant; promastigotes were 6 and 9 times, respectively, more resistant than the wild type, and amastigotes were 14 and 35 times, respectively, more resistant than the wild type. These data show that resistance to Pentostam induced in antimony-insensitive promastigotes is manifested in amastigotes as resistance both to pentavalent antimony and to chlorocresol. The axenic amastigote system is a unique tool which enables direct evaluation of the activity of antileishmanial compounds on the amastigote devoid of its host cell.

Full Text

The Full Text of this article is available as a PDF (255K).

Selected References

These references are in PubMed. This may not be the complete list of references from this article.
  • Assaraf YG, Drori S, Bachrach U, Shaugan-Labay V. Determination of multidrug resistance levels in cultured mammalian cells using ornithine decarboxylase activity. Anal Biochem. 1994 Jan;216(1):97–109. [PubMed]
  • Bates PA, Robertson CD, Tetley L, Coombs GH. Axenic cultivation and characterization of Leishmania mexicana amastigote-like forms. Parasitology. 1992 Oct;105(Pt 2):193–202. [PubMed]
  • Berman JD, Edwards N, King M, Grogl M. Biochemistry of Pentostam resistant Leishmania. Am J Trop Med Hyg. 1989 Feb;40(2):159–164. [PubMed]
  • Bodley AL, McGarry MW, Shapiro TA. Drug cytotoxicity assay for African trypanosomes and Leishmania species. J Infect Dis. 1995 Oct;172(4):1157–1159. [PubMed]
  • Chang KP, Dwyer DM. Multiplication of a human parasite (Leishmania donovani) in phagolysosomes of hamster macrophages in vitro. Science. 1976 Aug 20;193(4254):678–680. [PubMed]
  • Doyle PS, Engel JC, Pimenta PF, da Silva PP, Dwyer DM. Leishmania donovani: long-term culture of axenic amastigotes at 37 degrees C. Exp Parasitol. 1991 Oct;73(3):326–334. [PubMed]
  • Dwyer DM. Leishmania donovani: surface membrane carbohydrates of promastigotes. Exp Parasitol. 1977 Apr;41(2):341–358. [PubMed]
  • Joshi M, Dwyer DM, Nakhasi HL. Cloning and characterization of differentially expressed genes from in vitro-grown 'amastigotes' of Leishmania donovani. Mol Biochem Parasitol. 1993 Apr;58(2):345–354. [PubMed]
  • Mukhopadhyay R, Madhubala R. Leishmania donovani: cellular control of ornithine decarboxylase in promastigotes. Int J Biochem Cell Biol. 1995 Sep;27(9):947–952. [PubMed]
  • Naredi P, Heath DD, Enns RE, Howell SB. Cross-resistance between cisplatin, antimony potassium tartrate, and arsenite in human tumor cells. J Clin Invest. 1995 Mar;95(3):1193–1198. [PMC free article] [PubMed]
  • Roberts WL, Berman JD, Rainey PM. In vitro antileishmanial properties of tri- and pentavalent antimonial preparations. Antimicrob Agents Chemother. 1995 Jun;39(6):1234–1239. [PMC free article] [PubMed]
  • Roberts WL, Rainey PM. Antileishmanial activity of sodium stibogluconate fractions. Antimicrob Agents Chemother. 1993 Sep;37(9):1842–1846. [PMC free article] [PubMed]
  • Zilberstein D, Shapira M. The role of pH and temperature in the development of Leishmania parasites. Annu Rev Microbiol. 1994;48:449–470. [PubMed]

Articles from Antimicrobial Agents and Chemotherapy are provided here courtesy of American Society for Microbiology (ASM)


Related citations in PubMed

See reviews...See all...

Cited by other articles in PMC

See all...


Recent Activity

Your browsing activity is empty.

Activity recording is turned off.

Turn recording back on

See more...