Evaluation of Giardia intestinalis, Entamoeba histolytica and Cryptosporidium hominis/Cryptosporidium parvum in human stool samples by the BD MAX™ Enteric Parasite Panel

Abstract

Although the microscopic examination of stool samples remains the reference method of choice for the diagnosis of intestinal protistan infections, this method is time-consuming and requires experienced and well-trained operators. The purpose of this study was to evaluate the level of agreement between the BD MAX (TM) Enteric Parasite Panel (EPP) and microscopy for the detection of Giardia intestinalis (Lambl, 1859), Cryptosporidium spp. and Entamoeba histolytica Schaudinn, 1903 in stool samples. The study included faecal samples of 362 patients who were admitted to our hospital due to gastrointestinal complaints. In the microscopic examination, which was made with the native-lugol method on the stool samples that were taken from the patients, cysts, trophozoites and eggs of the parasite were examined. The diagnosis of G. intestinalis, Cryptosporidium parvum Tyzzer, 1912 and Cryptosporidium hominis Morgan-Ryan, Fall, Ward, Hijjawi, Sulaiman, Fayer, Thompson, Olson, Lal et Xiao, 2002, and E. histolytica was made in the faecal samples using the EPP assay. In the microscopic examination, Cryptosporidium spp. positive stool samples were stained with kinyoun's acid-fast. In the microscopic examination, parasites were detected in 41 (11%) of the 362 stool samples. In contrast, EPP assay identified parasites in 23 (6.3%) of the samples. In the microscopic examination, E. histolytica and Entamoeba disparBrumpt, 1925 were detected in 22 (6.1%) of the samples, G. intestinalis was seen in 15 (4.1%), and C. parvum or C. hominis were detected in three (0.8%); these values were five (1.4%), 16 (4.4%) and two (0.5%) positive with the EPP assay. Although C. parvum or C. hominis were detected as positive in the microscopic examination of three samples, only two of the samples were positive in both EPP assay and kinyoun's acid-fast method. The EPP assay is a relatively simple test that can distinguish E. histolytica and E. dispar, but it cannot replace microscopy in the diagnosis of amoebiasis. Diagnosis for G. intestinalis and C. parvum/C. hominis with the BD MAX (TM) enteric parasite panel was equivalent to that with microscopy. We believe that E. histolytica must be diagnosed with nucleic acid amplification tests that have a high sensitivity and specificity like EPP assay in certain patient groups.