Comparison of the Anaerocult A and the oil blocking methods for the in vitro cultivation of Entamoeba histolytica.

Entamoeba histolytica, the causative agent for human amoebiasis, is among the most deadly parasites, accounting for the second highest mortality rate among parasitic diseases. Because this parasite dwells in low oxygen tension, for its cultivation, microaerophilic conditions are required to mimick the human gut environment. Several methods developed for optimal growth environment are commercially available and some are conventionally modified in-house which include the Anaerocult A and oil blocking preparation methods. This study was undertaken to compare the reliability of the Anaerocult A and the oil blocking methods in generating anaerobic environment for cultivation of E. histolytica. The trophozoites of E. histolytica HM1: IMSS strains were axenically cultivated in TYI-S-33 medium in culture incubated anaerobically by using Anaerocult A (Merck) and mineral oil blocking method. The outcomes of both methods were determined by the minimum inhibitory concentration (MIC) of metronidazole against E. histolytica by giving a score to the growth pattern of the trophozoites. The reliability of both methods was assessed based on susceptibility testing of E. histolytica to metronidazole. The MIC obtained by both anaerobic condition methods was 6.25 ug/ ml, thus showing that oil-blocking method is comparable to the Anaerocult A method and therefore, considered as a reliable method for generating an anaerobic environment for the cultivation of E. histolytica.

Chronic Trichuris trichiura Infection Presenting as Ileocecal Valve Swelling Mimicking Malignancy.

A 46-year-old man presented with a history of passing bright red blood per rectum over the last one month. He also had on and off diarrhea with visible mucus in the stool for two months' duration. Further history was unremarkable, and physical examination revealed hemorrhoids which were subsequently banded. A colonoscopy was arranged in view of the prolonged diarrhea whereby an edematous and swollen ileocecal valve was seen. This was shown to be due to Trichuris trichiura infection, confirmed on histopathological examination of biopsies taken from the site. The patient was started on oral albendazole treatment and has been asymptomatic on latest followup. This case illustrates an accidental finding of T. trichuria infection on colonoscopic examination, which was done to investigate the patient's prolonged diarrhea.