Detection of Campylobacter in Stool and Determination of Significance by Culture, Enzyme Immunoassay, and PCR in Developing Countries

Campylobacter is a common bacterial enteropathogen that can be detected in stool by culture, enzyme immunoassay (EIA), or PCR. We compared culture forC. jejuni/C. coli , EIA (ProSpecT), and duplex PCR to distinguishCampylobacter jejuni/C. coli and non-jejuni/coli Campylobacter on 432 diarrheal and matched control stool samples from infants in a multisite longitudinal study of enteric infections in Tanzania, Bangladesh, and Peru. The sensitivity and specificity of culture were 8.5% and 97.6%, respectively, compared with the results of EIA and 8.7% and 98.0%, respectively, compared with the results of PCR forC. jejuni/C. coli . Most (71.6%) EIA-positive samples were positive by PCR forC. jejuni/C. coli , but 27.6% were positive for non-jejuni/coli Campylobacter species. Sequencing of 16S rRNA from 53 of these non-jejuni/coli Campylobacter samples showed that it most closely matched the 16S rRNA ofC. hyointestinalis subsp.lawsonii (56%),C. troglodytis (33%),C. upsaliensis (7.7%), andC. jejuni/C. coli (2.6%).Campylobacter -negative stool spiked with each of the above-mentionedCampylobacter species revealed reactivity with EIA. PCR detection ofCampylobacter species was strongly associated with diarrhea in Peru (odds ratio [OR] = 3.66,P < 0.001) but not in Tanzania (OR = 1.56,P = 0.24) or Bangladesh (OR = 1.13,P = 0.75). According to PCR,Campylobacter jejuni/C. coli infections represented less than half of all infections withCampylobacter species. In sum, in infants in developing country settings, the ProSpecT EIA and PCR forCampylobacter reveal extremely high rates of positivity. We propose the use of PCR because it retains high sensitivity, can ascertain burden, and can distinguish betweenCampylobacter infections at the species level.