Nitazoxanide microbiology
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Ahmed Zaghw, M.D. [2]
Microbiology
Mechanism of Action
The antiprotozoal activity of nitazoxanide is believed to be due to interference with the pyruvate:ferredoxin oxidoreductase (PFOR) enzyme-dependent electron transfer reaction which is essential to anaerobic energy metabolism. Studies have shown that the PFOR enzyme from Giardia lamblia directly reduces nitazoxanide by transfer of electrons in the absence of ferredoxin. The DNA-derived PFOR protein sequence of Cryptosporidium parvum appears to be similar to that of Giardia lamblia. Interference with the PFOR enzyme-dependent electron transfer reaction may not be the only pathway by which nitazoxanide exhibits antiprotozoal activity.
Activity in vitro
Nitazoxanide and its metabolite, tizoxanide, are active in vitro in inhibiting the growth of (i) sporozoites and oocysts of Cryptosporidium parvum and (ii) trophozoites of Giardia lamblia (iii) Entamoeba histolytica.11:28, 25 November 2014 (UTC)AKAZamkz12 (talk)
Drug Resistance
A potential for development of resistance by Cryptosporidium parvum or Giardia lamblia to nitazoxanide has not been examined.
Susceptibility Tests
For protozoa such as Cryptosporidium parvum and Giardia lamblia, standardized tests for use in clinical microbiology laboratories are not available[1]
References
Adapted from the FDA Package Insert.
Rossignol JF, Kabil SM, El-Gohary Y, Younis AM. (2007) Nitazoxanide i n the treatment of amoebiasis. Trans R Soc Trop Med Hyg 101: 1025-1031 doi.10.1016/jtrsmth.2007.04.001