The use of the antifungal agent miconazole as an inhibitor of Blastocystis hominis growth in Entamoeba histolytica/E. dispar cultures

In regions with high prevalence, Blastocystis hominis is frequently found in association with Entamoeba histolytica/E. dispar in xenic cultures. Its exacerbated growth is often superimposed on the growth of amebas, thus impeding the continuation of the amebas in the culture, within a few generations. The present study reports on the excellent efficacy (100 percent) of the antifungal agent miconazole in eliminating B. hominis from cultures of E. histolytica/E. dispar, thereby maintaining the integrity of the trophozoites of the amebas. Nystatin presented low efficacy (33.3 percent).

Em regiões de alta prevalência, Blastocystis hominis é freqüentemente encontrado em associação com Entamoeba histolytica/E. dispar em cultivos xênicos. Seu crescimento exacerbado se sobrepõe muitas vezes ao das amebas, impedindo a manutenção destas em cultura, dentro de poucas gerações. O presente estudo relata a excelente eficácia (100 por cento) do antifúngico miconazol na eliminação de B. hominis dos cultivos de E. histolytica/E. dispar, mantendo-se a integridade dos trofozoítos das amebas. A nistatina apresentou eficácia baixa (33,3 por cento).

Evaluation of the in vitro effect of Nigella sativa aqueous extract on blastocystis hominis isolates

The effect of Nigella sativa aqueous extract was evaluated against the in vitro growth of 2 different isolates of the intestinal protozoan parasite Blastocystis hominis. Different concentrations [10, 100, 500 microg/ml] of Nigella aqueous extract and metronidazole, an active standard drug for B. hominis, were incubated with B. hominis isolates in culture media at 37°C. Their possible effect on B. hominnis living cell count [LCC] was assessed on Day 1, 3 and 6. The aqueous extract of N. sativa at concentrations of 100 and 500 microg/ml showed a potent lethal effect on both B. hominis isolates, but with different extent. There is no significant difference between the inhibitory effect of N. sativa and metronidazole on the LCC on the 6[th] day. On assessment of living cell rate [LCR] which calculate percentage rate of living cell, N. sativa at 500 microg/ml concentration has a significant inhibitory effect on both isolates. So, it is considered as the most active concentration of Nigella aqueous extract. These results prove that N. sativa aqueous extract could be useful in the treatment of B. hominis

Polypeptides associated with in vitro cyst formation of Blastocystis hominis.

The objective of this study was to characterize the polypeptides associated with cysts of Blastocystis hominis. This form is believed to be infective and plays a role in parasite resistance to anti-B. hominis drugs currently used for treatment of Blastocystis associated diarrhea. Cysts were induced through in vitro culture of the parasite in complete medium supplemented with bacterial extract with trypticase, metronidazole or doxycycline. SDS-PAGE analysis showed almost similar polypeptide patterns of parasite extracts obtained from in vitro cultured parasites before and after exposure with the three supplements. Polypeptide bands at 76, 58.5, 48, 45, 40, 38, 32, 25 and 22 kDa were constantly seen in all antigenic preparations and no specific cyst-associated polypeptide was present. However, on immunoblot analysis, 3 out of 16 blastocystosis human sera identified a cyst-associated polypeptide at 60 kDa in all parasite extracts prepared from cultures with the three supplements. In addition, there were associated morphological changes detected in these parasites stained with acridine orange and observed under fluorescence microscopy. Metronidazole induced cyst forms (reddish cells) as early as 12 hours post-exposure; more cyst production (with stronger immunoblot bands) occurred after 24 hours exposure. However, cysts rupture with release and destruction of B. hominis daughters cells occurred after 48 hours exposure. Doxycycline induced less cyst-like forms at 24 hours (weaker 60 kDa band) and less destruction of the cysts (60 kDa band still present at 72 hours post exposure). Bacterial extract and trypticase also induced cysts at 12 hours with increasing numbers up to 72 hours exposure (corresponding increase in intensity of 60 kDa band from samples harvested at 12 to 72 hours post exposure) without any sign of deleterious effect on the parasite.