Enteric campylobacteria and RNA viruses associated with healthy and diarrheic humans in the Chinook health region of southwestern Alberta, Canada

Abstract

The presence of Campylobacter species and enteric RNA viruses in stools from diarrheic (n = 442) and healthy (n = 58) humans living in southwestern Alberta was examined (May to October 2005). A large number of diarrheic individuals who were culture negative for C. jejuni (n = 54) or C. coli (n = 19) were PCR positive for these taxa. Overall detection rates for C. jejuni and C. coli in diarrheic stools were 29% and 5%, respectively. In contrast, 3% and 0% of stools from healthy humans were positive for these taxa, respectively. Infection with C. jejuni was endemic over the study period. However, there was no difference in infection rates between individuals living in urban or rural locations. Stools from a large number of diarrheic (74%) and healthy (88%) individuals were positive for Campylobacter DNA. The prevalence rates of C. concisus, C. curvus, C. fetus, C. gracilis, C. helveticus, C. hominis, C. hyointestinalis, C. mucosalis, C. showae, C. sputorum, and C. upsaliensis DNA were either not significantly different or were significantly lower in stools from diarrheic than from healthy individuals. No C. lanienae or C. lari DNA was detected. Stools from 4% and 0% of diarrheic and healthy humans, respectively, were positive for rotavirus, sapovirus, or norovirus (GI/GII). Our results showed a high prevalence of diarrheic individuals living in southwestern Alberta who were infected by C. jejuni and, to a lesser extent, by C. coli. However, other Campylobacter species, norovirus, rotavirus, sapovirus, and bovine enteric calicivirus were either inconsequential pathogens during the study period or are not pathogens at all.

FIG. 1.

Detection of campylobacteria in seeded feces by using nested primers. (A) Campylobacter concisus 23S rRNA gene primers; (B) C. concisus cpn60 primers; (C) C. upsaliensis glyA primers. Campylobacter species were inoculated into swine feces. Lane assignments: M, 100-bp marker; 1, feces seeded at 2 × 10⁵ cells/g; 2, feces seeded at 2 × 10⁴ cells/g; 3, feces seeded at 2 × 10³ cells/g; 4, feces seeded at 1 × 10³ cells/g; 5, feces seeded at 2 × 10² cells/g; 6, feces seeded at 1 × 10² cells/g; 7, uninoculated feces. Genomic DNA of C. concisus or C. upsaliensis and water alone (instead of template) were run in all gels (data not shown). In all instances, amplicon size from seeded feces corresponded to that of the corresponding taxon, and PCR controls were always negative.

FIG. 2.

Sensitivity of published and new primers for detection of Campylobacter cells in seeded swine feces. (A) Campylobacter concisus; (B) C. upsaliensis.

FIG. 3.

Temporal Campylobacter detection rates in humans living in the former Chinook Health Region from 31 May to 31 October 2005 (n = 442). (A) Campylobacter genus; (B) C. jejuni; (C) C. concisus and/or C. showae. In panel B, black bars indicate culture-positive detection of C. jejuni, hatched bars indicate PCR-positive but culture-negative results for C. jejuni, and open bars indicate negative individuals. In panel C, black bars indicate positive PCR detection of C. concisus based on the nested cpn60 primers, hatched bars indicate positive PCR detection of C. concisus/C. showae using the 23S rRNA primers, and open bars indicate negative individuals.