The efficacy of modified Ziehl-Neelsen (MZN) and enzyme linked immunosorbent assay (ELISA) and molecular techniques for detection of cryptosporidia in the stool of gastrointestinal cancer Sudanese patients

Abstract

Background: Cryptosporidiosis diagnosis based on demonstration of the parasite microscopically in the stool through modified Ziehl-Neelsen (MZN) or auramine phenol staining techniques. The primary goal of this study was to compare between the efficacy of cryptospridia antigen detection potential in the fecal specimens using ELISA and Oocyst detection by MZN staining methods and molecular techniques for the diagnosis of human cryptosporidiosis among some Sudanese patients with gastrointestinal cancer. One hundred and eighty-one patients suspected of having gasterointestinal cancer based on their clinical presentation were enrolled in this study. Cryptosporidiosis was diagnosed using polymerase chain reaction (PCR). MZN staining was conducted for fresh stool samples to detect Cryptosporidium Oocyst. Results: Of 181 cancer suspected patients, 55 (30.5%) were confirmed as having gastrointestinal cancer. Of the 55 cancer patients 41(74.5%) were confirmed as having colorectal cancer, 7 (12.7%) small intestine cancer, 4(7.3%) liver cancer, 3(5.5%) esophageal cancer. Of the confirmed cancer patients MZN identified 24 (43.6%) and ELISA identified 31(56.4%) as having cryptospridia Oocyst and antigens in their fecal samples, respectively. Based on PCR outcome, the infection rates was significantly higher in colorectal cancer patients than in other cancer patients (P = 0.02). Depending on the criteria of ‘true positive’ samples, sensitivity of MZN and ELISA was 81.06% and 94.25% respectively. Conclusions: Fecal antigen ELISA detection test has the advantage of accurate diagnosis of Cryptosporidiosis over MZN staining technique especially in immunocompromised patients.