“Candidatus Campylobacter infans” detection is not associated with diarrhea in children under the age of 2 in Peru

Authors: GARCIA BARDALES, P - Prisma Charitable Association; SCHIAFFINO, FRANCESCA - Universidad Peruana; Huynh, Steven; PAREDES OLORTEGUI, M - Prisma Charitable Association; PENATARO YORI, P - University Of Virginia School Of Medicine; PINEDO VASQUEZ, T - Prisma Charitable Association; VILLANEUVA, K - Prisma Charitable Association; CURICO HUANSI, G - Prisma Charitable Association; SHAPIAMA LOPEZ, W - Prisma Charitable Association; COOPER, KERRY - University Of Arizona; Parker, Craig; KOSEK, MARGARET - University Of Virginia

Submitted to: PLOS Neglected Tropical Diseases
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/13/2022
Publication Date: 10/17/2022
Citation: Garcia Bardales, P., Schiaffino, F., Huynh, S., Paredes Olortegui, M., Penataro Yori, P., Pinedo Vasquez, T., Manzanares Villaneuva, K., Curico Huansi, G., Shapiama Lopez, W., Cooper, K.K., Parker, C.T., Kosek, M.N. 2022. “Candidatus Campylobacter infans” detection is not associated with diarrhea in children under the age of 2 in Peru. PLOS Neglected Tropical Diseases. 16(10). Article e0010869. https://doi.org/10.1371/journal.pntd.0010869.
DOI: https://doi.org/10.1371/journal.pntd.0010869

Interpretive Summary: Campylobacters are leading causes of bacterial foodborne illness in Peru and other low- and middle-income countries (LMIC). Campylobacter sp. are also associated with high rates of mortality and deficits in early childhood development for children in LMIC. Campylobacter jejuni and C. coli are most often the causative agents of enteric disease among children in LMIC. However, a potential new species of Campylobacter, "Candidatus Campylobacter infans" has been found in stool samples from children in LMIC settings in Southeast Asia and Africa. We designed a qPCR assay to determine the presence of Campylobacters and specifically "Candidatus Campylobacter infans". This study determined its prevalence using qPCR in diarrhea and non-diarrheal samples of children under the age of two and confirmed results using shotgun metagenomics. The presence of “Candidatus Campylobacter infans” was not associated with diarrhea in this population.

Technical Abstract: A working hypothesis is that less common species of Campylobacter (other than C. jejuni and C. coli) play a role in enteric disease among children in low resource settings and explain the gap between the detection of Campylobacter using culture and culture independent methods. “Candidatus Campylobacter infans” (C. infans), was recently detected in stool samples from children and hypothesized to play a role in Campylobacter epidemiology in low- and middle-income countries (LMIC). This study determined the prevalence of C. infans in symptomatic and asymptomatic stool samples from children living in Iquitos, Peru. Stool samples from 215 children with diarrhea and 50 stool samples from children without diarrhea under the age of two were evaluated using a multiplex qPCR assay to detect Campylobacter spp. (16S rRNA), Campylobacter jejuni / Campylobacter coli (cadF gene), C. infans (lpxA), and Shigella spp. (ipaH). C. infans was detected in 7.9% (17/215) symptomatic samples and 4.0% (2/50) asymptomatic samples. The association between diarrhea and the presence of these targets was evaluated using univariate logistic regressions. C. infans was not associated with diarrhea. Fifty-one percent (75/146) of Campylobacter positive fecal samples were negative for C. jejuni, C. coli, and C. infans via qPCR. Shotgun metagenomics confirmed the presence of C. infans among 13 out of 14 positive C. infans positive stool samples. C infans explained only 20.7% of the diagnostic gap in stools from children with diarrhea and 16.7% of the gap in children without diarrhea. We posit that poor cadF primer performance better explains the observed gap than the prevalence of atypical non-C. jejuni/coli species.