In vitro evaluation of activities of nitazoxanide and tizoxanide against anaerobes and aerobic organisms

Abstract

The antibacterial activities of nitazoxanide and its main metabolite, tizoxanide, were tested against a broad range of bacteria, including anaerobes. Metronidazole, amoxicillin, amoxicillin-clavulanic acid, piperacillin, cefoxitin, imipenem, and clindamycin were used as positive controls. MICs were determined by reference agar dilution methods. The 241 anaerobes were all inhibited by nitazoxanide, with the MICs at which 90% of isolates are inhibited (MIC 90 s) being between 0.06 and 4 mg/liter with the exception of those for Propionibacterium species, for which the MIC 90 was 16 mg/liter. The MIC 90 s of nitazoxanide were 0.5 mg/liter for the Bacteroides fragilis group (80 strains), 0.06 mg/liter for Clostridium difficile (21 strains), and 0.5 mg/liter for Clostridium perfringens (16 strains). Metronidazole showed a level of activity comparable to that of nitazoxanide except against Bifidobacterium species, against which it was poorly active, and Propionibacterium species, which were resistant to metronidazole. The other antibiotics showed various levels of activity against anaerobes, with imipenem along with nitazoxanide being the most active agents tested. Tizoxanide was less effective than nitazoxanide except against the B. fragilis group, against which its activity was similar to that of nitazoxanide. Under aerobic conditions, nitazoxanide demonstrated poor activity against members of the family Enterobacteriacae and Pseudomonas, Staphylococcus, and Enterococcus species. The same results were obtained when culture was performed under anaerobic conditions with the notable exception of the results against Staphylococcus aureus. The MICs of nitazoxanide were in the range of 2 to 4 mg/liter for 34 clinical isolates of S. aureus, 12 of which were methicillin resistant, while tizoxanide was not effective.

Nitazoxanide suppresses IL-6 production in LPS-stimulated mouse macrophages and TG-injected mice

“…In humans, nitazoxanide has been approved by the US FDA for the treatment of diarrhea caused by Cryptosporidium parvum and G. lamblia infection in children 1-11 years of age [18]. Nitazoxanide also has potent antibacterial activity against a variety of anaerobic and aerobic bacteria [19], including Helicobacter pylori [20]. Recent in vitro studies have shown that nitazoxanide is effective against the canine influenza virus [11].…”

Liquid chromatography–tandem mass spectrometry analysis of nitazoxanide and its major metabolites in goat

“…The broad spectrum of in vivo activity is related to its desacetyl derivative, tizoxanide, and includes intracellular and extracellular protozoa, helminthes, aerobic and anaerobic bacteria, and virus [1][2][3][4][5][6][7][8]. The Food and Drug Administration has approved this drug in December 2002 for treatment of diarrhea caused by Cryptosporidium parvum and Giardia lamblia, in children 1-11 years of age [9].…”

The use of nitazoxanide against the pathogens Ichthyophthirius multifiliis and Aeromonas hydrophila in silver catfish (Rhamdia quelen)

“…Nitazoxanide is effective against several gram-positive and gram-negative bacteria, specifically Bacteroides and Clostridium species, Helicobacter pylori, Mycobacterium tuberculosis and bacteria of genus Staphylococcus (Dubreuil et al, 1996;Megraud et al, 1998;Tchouaffi-Nana et al, 2010;de Carvalho et al, 2011). In this study NTZ did not show inhibitory activity in vitro against A. hydrophila.…”

“…Nitazoxanide [2-[(5-nitro-1,3-thiazol-2-yl)carbamoyl] phenyl] acetate (NTZ) has broad-spectrum antiparasitic activity, acting in a wide spectrum of protozoa parasites in humans, such as amoebas, flagellates, sporozoans and ciliates (Abaza et al, 1998), as well as bacteria (Dubreuil et al, 1996;de Carvalho et al, 2011). Therefore, based on the needs of a therapy against ichthyophthiriasis and infections by A. hydrophila, the antiparasitic and antibacterial potential of NTZ was analyzed for the first time in fish infected by these pathogens.…”