Molecular-based detection of non-culturable and emerging campylobacteria in patients presenting with gastroenteritis

From January 2009 to May 2010, 436 faecal samples from patients with diarrhoeal illness in Southern Ireland were identified as Campylobacter genus-positive by an automated multiplex PCR; however, 204 (46.8%) of these samples were culture-negative for campylobacters. A combination of Campylobacter-specific uniplex PCR and 16S rRNA sequencing confirmed the presence of Campylobacter DNA in 191 (93.6%) of the culture-negative samples. Species-specific PCR identified C. jejuni (50.7%) C. ureolyticus (41%) and C. coli (5.7%) as the most prevalent species while C. fetus, C. upsaliensis, C. hyointestinalis and C. lari accounted for 10% of culture-negative samples; mixed Campylobacter spp. were detected in 11% of samples. We conclude that non-culturable Campylobacter spp. are responsible for a considerable proportion of human enteritis and the true incidence of infection is likely to be significantly underestimated where conventional Campylobacter culture methods are used in isolation.