A comparative study of conventional and molecular techniques in diagnosis of campylobacter gastroenteritis in children.

BACKGROUND Campylobacter species are a significant cause of gastroenteritis among children worldwide. Conventional methods for detection of Campylobacter spp. based on cultural isolation and biochemical tests are cumbersome and time consuming. Because of their superior sensitivity and cost effectiveness, molecular methods are often used for identification of the pathogens. AIMS To evaluate different diagnostic methods for identification of Campylobacter. MATERIALS AND METHODS Faecal samples were collected from 585 children (age ≤ 12 years) with acute diarrhoea admitted in a tertiary-care hospital, excluding children already on antimicrobial therapy. All samples were examined by four methods: Grams' staining, culture methods, Enzyme-Immuno Assay, and Polymerase Chain Reaction (PCR). After Grams' staining, samples were inoculated on modified charcoal cefoperazone deoxycholate agar. ProSpecT™ Microplate Assay® and PCR assay using cadF gene was done for detection of Campylobacter specific antigen and DNA, respectively, in faecal samples. McNemar's test was used to compare the results wherever applicable. RESULTS 197 cases (33.67%) were found to be positive for Campylobacter by at least one method. But only 121 (20.78%) out of the 585 stool specimens tested fulfilled the positivity criteria, i.e., positive either by culture or by any two tests among other three. Culture had very low sensitivity (37.19%), whereas PCR had the highest (96.69%) sensitivity but lowest positive predictive value (86.03%). Rapid Grams' staining technique (sensitivity 63.64%) was found to be better than culture. Detection by PCR and ELISA was significantly better than by culture on selective media and Grams' staining (p<0.0001). CONCLUSIONS Molecular techniques significantly increased detection rates of Campylobacter in children with diarrhoea. However, enzyme-immuno assay with high accuracy has the advantage of applicability in resource-poor settings.