The entire system of the human gut microbiota functions as a ‘microbial organ’ within

the intestine, which contributes to diverse mammalian processes including protective functions against pathogens and immune-system modulation, the metabolic function of fermenting non-digestible dietary fiber, anaerobic metabolism of peptides and proteins that results in the recovery of metabolic energy for the host [7]. The microbial diversity of the human gut is the result of co-evolution between microbial communities Selleck Sapitinib and their hosts. Microbial community structure is a very important factor that can influence predisposition to specific diseases in certain host contexts [8]. Ingestion selleck inhibitor of the cyst of E. histolytica through fecally contaminated food or water initiates infection. Excystation in the intestinal lumen produces trophozoites and colitis results when the trophozoites penetrate the mucus layer and damages intestinal tissues [9]. The trophozoites proliferate in lumen and phagocytose

resident flora. E. histolytica trophozoites are quite selective in respect to their interactions with different bacterial species and only those bacteria which have the appropriate recognition molecules get attached and ingested [10]. It has been observed that the nuclear DNA content of E. histolytica trophozoites growing in axenic cultures is at least 10 fold higher than in xenic cultures and re-association of axenic cultures with their bacterial flora led to a reduction of DNA content attaining the original xenic values indicating a flexible nature of the parasite genome [11]. Fluctuations in gut flora have been reported both in acute diarrhea and antibiotic associated diarrhea [12], but very few reports are available on status of gut flora

in E. histolytica infected individuals. Earlier studies in our laboratory [1] have recorded fluctuations in the gut flora by a qualitative method during check disease conditions. 5-Nitroimidazole drugs are still used as first line of defense against amoebic and other infections caused by anaerobes. These drugs are administered as pro drugs and one electron reduction of nitro group converts the pro drug into an active drug [13]. Enzymatic modification mediated by nim-class of genes is a well characterized resistance mechanism. Certain Bacteroides species which are members of the normal colonic human microflora harbor nim genes [14]. Our study is based on the hypothesis that the Entamoeba histolytica (but not E. dispar) is an KU55933 purchase invasive organism and invades the mucus layer and subsequently the intestinal epithelium for colonization using the pathogenic factors.