Comparison between different methods of Blastocystis hominis detection in stool samples.

Blastocystis hominis is common protozoan in human intestinal tract and can cause so-called blastocystosis characterized by diarrhea. Its routine identification in clinical laboratories is made by detection of vacuolar form in stool samples using wet mount smears. The present study was carried out with the aim of evaluating the effectiveness of different techniques for diagnosis of  B. hominis in the stool samples from the patients attended Brack Hospital and Medical Technology Department, Faculty of Engineering and Technology, Brack. A total of 360 stool samples were collected form randomized patients, presenting different genders and ages (121 males and 239 females ,and aged from less than one year to 90 years), residing in different localities of Wadi Al-shati province. All specimens were examined by direct smear microscopy (normal saline, iodine, and eosin stains), concentration (formalin–ether sedimentation) and two xenic culture systems (Monophasic Jone’s medium and Diphasic Boeck and Drbohlav's ) for the detection of  B. hominis. The results highlights the low sensitivity of direct smear microscopy (11.29%) compared to concentration method (15.5%) and  in-vitro culture methods (22.60%). There was no significant difference (p>0.05) between direct smear preparations, and concentration method, meanwhile there was significant difference (p 0.05) was found between the two culture methods. Diphasic Boeck and Drbohlav’s medium produced highest numbers (7.600±6.379) of  B. hominis cells compared to Monophasic Jone’s medium (5.051±4.938) after every passage cultures and only the vacuolar morphologic type of this organism was found in both culture systems. Moreover, a larger size of vacuolar stage of  B. hominis detected in Diphasic Boeck and Drbohlav's medium, than in Monophasic Jone's medium. In vitro cultivation does seem worthwhile in the detection of  B. hominis in diagnostic laboratories. Of all the diagnostic techniques used, diphasic Boeck and Drbohlav's medium was the most sensitive method for detecting  B. hominis in stool specimens. The short-term  in vitro culture methods achieved the best performance with regard to sensitivity with other studied methods. With the advantages in terms of sensitivity, the  in vitro culture methods could be applied to identify  B. hominis for both clinical diagnosis and field study purposes, thus indicating the need to include laboratory techniques that enable  B. hominis detection on a routine basis.