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

Abstract

iCampylobacter is a common bacterial enteropathogen that can be detected in stool by culture, enzyme immunoassay (EIA), or PCR. We compared culture for C. jejuni/C. coli, EIA (ProSpecT), and duplex PCR to distinguish Campylobacter 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 for C. jejuni/C. coli. Most (71.6%) EIA-positive samples were positive by PCR for C. jejuni/C. coli, but 27.6% were positive for nonjejuni/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 of C. hyointestinalis subsp. lawsonii (56%), C. troglodytis (33%), C. upsaliensis (7.7%), and C. jejuni/C. coli (2.6%). Campylobacter-negative stool spiked with each of the above-mentioned Campylobacter species revealed reactivity with EIA. PCR detection of Campylobacter 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 with Campylobacter species. In sum, in infants in developing country settings, the ProSpecT EIA and PCR for Campylobacter reveal extremely high rates of positivity. We propose the use of PCR because it retains high sensitivity, can ascertain burden, and can distinguish between Campylobacter infections at the species level.

Multicenter Evaluation of Clinical Diagnostic Methods for Detection and Isolation of Campylobacter spp. from Stool

“…In the case of stool antigen tests for Campylobacter antigen detection, cross-reactivity with species of Campylobacter other than C. jejuni or C. coli has been reported (18)(19)(20)(21), so perhaps these other Campylobacter species present in the stool samples account for discordant results. In our study, we had an insufficient number of other identified species, such as C. upsaliensis (n ϭ 1) and C. showae (n ϭ 1), to make any conclusion about the ability of stool antigen CIDTs to detect these species (see Table S2 in the supplemental material).…”

“…A study of infants with diarrhea in developing countries of South America found ProSpecT to have 60.6% sensitivity and 88.8% specificity for C. jejuni/C. coli infections (18). Our prospective multicenter study included 2,767 samples with 86 culturepositive patients (3.1% prevalence).…”

Global Epidemiology of Campylobacter Infection

“…In Peru, a study that included 150 pediatric stool samples from the Etiology, Risk Factors and Interactions of Enteric Infections and Malnutrition and the Consequences for Child Health and Development (MAL-ED) cohort study detected C. jejuni/C. coli in 41.3% of the children with gastroenteritis and 18.7% of the controls (P ϭ 0.007) (45). In contrast, the difference in the prevalences of other Campylobacter species, including C. hyointestinalis subsp.…”

Commentary: Revisiting the Roles of Culture and Culture-Independent Detection Tests for Campylobacter

“…Though cross-reactivity with other Campylobacter species has been reported for stool antigen CIDTs previously, the authors did not investigate this aspect of the analytical specificity of the assays (9)(10)(11)(12). Nonetheless, it is important to consider that noncases were typically not clinically compatible with the positive stool antigen CIDT results, which argues against the idea that false-positive results are largely attributable to pathogenic Campylobacter spp.…”

“…While some studies have described excellent sensitivity and specificity versus conventional Campylobacter culture, sometimes with enhanced sensitivity compared to culture (5,6), others have reported poor specificity and variable sensitivity (7)(8)(9)(10). Still others have shown that these assays potentially have broader detection within the Campylobacter genus than what the manufacturers have indicated in their instructions for use (further complicating the true analytical performance) (9)(10)(11)(12). This collective body of work has culminated in a quagmire of conflicting/ inconsistent data and even contentious opinions as to the best use of these assays (if any) for clinical care in the diagnosis and reporting of campylobacteriosis.…”