Comparison of an Immunochromatographic Rapid Test, a Microplate Enzyme Immunoassay and Traditional Culture Methods for Detection of Campylobacter spp. in Outpatient Stool Samples

Background: Campylobacter is a leading cause of bacterial gastroenteritis, affecting over 2.4 million persons annually. Campylobacteriosis infection is caused by consuming unpasteurized milk, contaminated food or water, or undercooked poultry. Food poisoning caused by Campylobacter spp. can be debilitating, resulting in diarrhea with varying severity from loose to bloody stools. An analytical review of recent publications suggests a problem with consistent detection of Campylobacter, therefore a comparison of antigen detection approaches versus culture methods needs to be conducted.The objectives were to compare antigen detection methods, to compare sensitivity for recovery of Campylobacter using culture versus enzyme immunoassay, and to tabulate incidence of bacterial, parasitic, and viral pathogens. Methods: Three diagnostic methods were performed on 100 stool samples collected from outpatients. ProSpecT™  EIA Test and ImmunoCard STAT! CAMPY® enzyme immunoassays detected Campylobacter antigens.  Traditional culture on Campylobacter selective medium and filtration on blood agar was also performed. Campylobacter is a seagull-shaped gram negative bacilli, catalase positive, oxidase positive, hippurate positive, and motile. Disc diffusion susceptibility to nalidixic acid, cephalothin, and erythromycin further identified the species. Results and Conclusions: Antigen detection tests recovered seven positives, whereas culture methods recovered three positives. The gold standard was two-fold. When culture served as reference, sensitivity/specificity were high (both >65%); ImmunoSTAT! positive predictive value was 28%. When positive EIA or culture served as reference, ImmunoSTAT! sensitivity decreased, but positive predictive value increased. The highest incidence of enteric pathogens was Campylobacter and Clostridium difficile. Consistently reliable identification of Campylobacter spp. is crucial for diagnosis of the leading cause of enteritis globally.