Commensal Escherichia coli Strains of Bovine Origin Competitively Mitigated Escherichia coli O157:H7 in a Gnotobiotic Murine Intestinal Colonization Model with or without Physiological Stress.

Cattle are a primary reservoir of enterohemorrhagic Escherichia coli (EHEC) O157:H7. Currently, there are no effective methods of eliminating this important zoonotic pathogen from cattle, and colonization resistance in relation to EHEC O157:H7 in cattle is poorly understood. We developed a gnotobiotic EHEC O157:H7 murine model to examine aspects of the cattle pathogen-microbiota interaction, and to investigate competitive suppression of EHEC O157:H7 by 18 phylogenetically distinct commensal E. coli strains of bovine origin. As stress has been suggested to influence enteric colonization by EHEC O157:H7 in cattle, corticosterone administration (±) to incite a physiological stress response was included as an experimental variable. Colonization of the intestinal tract (IT) of mice by the bovine EHEC O157:H7 strain, FRIK-2001, mimicked characteristics of bovine IT colonization. In this regard, FRIK-2001 successfully colonized the IT and temporally incited minimal impacts on the host relative to other EHEC O157:H7 strains, including on the renal metabolome. The presence of the commensal E. coli strains decreased EHEC O157:H7 densities in the cecum, proximal colon, and distal colon. Moreover, histopathologic changes and inflammation markers were reduced in the distal colon of mice inoculated with commensal E. coli strains (both propagated separately and communally). Although stress induction affected the behavior of mice, it did not influence EHEC O157:H7 densities or disease. These findings support the use of a gnotobiotic murine model of enteric bovine EHEC O157:H7 colonization to better understand pathogen-host-microbiota interactions toward the development of effective on-farm mitigations for EHEC O157:H7 in cattle, including the identification of bacteria capable of competitively colonizing the IT.

Molecular Epidemiological Evidence Implicates Cattle as a Primary Reservoir of Campylobacter jejuni Infecting People via Contaminated Chickens.

The study aimed to determine the relative contribution of cattle to the burden of illness in a model agroecosystem with high rates of human campylobacteriosis (≥ 115 cases/100 K), and high densities of cattle, including large numbers of cattle housed in confined feeding operations (i.e., in southwestern Alberta, Canada). To accomplish this, a large-scale molecular epidemiological analysis of Campylobacter jejuni circulating within the study location was completed. In excess of 8000 isolates of C. jejuni from people (n = 2548 isolates), chickens (n = 1849 isolates), cattle (n = 2921 isolates), and water (n = 771 isolates) were subtyped. In contrast to previous studies, the source attribution estimates of clinical cases attributable to cattle vastly exceeded those attributed to chicken (i.e., three- to six-fold). Moreover, cattle were often colonized by C. jejuni (51%) and shed the bacterium in their feces. A large proportion of study isolates were found in subtypes primarily associated with cattle (46%), including subtypes infecting people and those associated with chickens (19%). The implication of cattle as a primary amplifying reservoir of C. jejuni subtypes in circulation in the study location is supported by the strong cattle association with subtypes that were found in chickens and in people, a lack of evidence indicating the foodborne transmission of C. jejuni from beef and dairy, and the large number of cattle and the substantial quantities of untreated manure containing C. jejuni cells. Importantly, the evidence implicated cattle as a source of C. jejuni infecting people through a transmission pathway from cattle to people via the consumption of chicken. This has implications for reducing the burden of campylobacteriosis in the study location and elsewhere.

Infection by Salmonella enterica Serovar Typhimurium DT104 Modulates Immune Responses, the Metabolome, and the Function of the Enteric Microbiota in Neonatal Broiler Chickens.

Salmonella enterica serovar Typhimurium incites salmonellosis in many different species including chickens and human beings. Acute salmonellosis was studied in neonatal broiler chicks by orally inoculating 2-day-old chicks with S. Typhimurium DT104. The temporal impact of disease (1, 2, and 4 days post-inoculation) on the structure and function of the enteric microbiota, on the bird's immune response in the ileum, cecum, and colon, and on the metabolome of digesta, breast muscle, liver, serum, and hippocampus were examined. Substantive histopathologic changes were observed in the small and large intestine, including the colon of chicks inoculated with S. Typhimurium, and increased in magnitude over the experimental time period. A variety of inflammatory genes (IFNγ, IL8, IL10, INOS, MIP1ß, TGFß2, TLR4, and TLR15) were temporally regulated. In addition, the metabolome of ileal digesta, breast muscle, liver, serum, and hippocampus was temporally altered in infected chicks. Although the structure of bacterial communities in digesta was not affected by S. Typhimurium infection, metabolomic analysis indicated that the function of the microbiota was changed. Collectively, the study findings demonstrate that infection of neonatal chicks by S. Typhimurium imparts a temporal and systemic impact on the host, affecting the immune system, the metabolome, and the function of the enteric microbiota.

Microbiota Transplantation in Day-Old Broiler Chickens Ameliorates Necrotic Enteritis via Modulation of the Intestinal Microbiota and Host Immune Responses.

A microbiota transplant (MT) originating from mature adult chicken ceca and propagated in bioreactors was administered to day-old broiler chicks to ascertain the degree to which, and how, the MT affects Clostridium perfringens (Cp)-incited necrotic enteritis (NE). Using a stress predisposition model of NE, birds administered the MT and challenged with Cp showed fewer necrotic lesions, and exhibited a substantially higher α- and ß-diversity of bacteria in their jejunum and ceca. Birds challenged with Cp and not administered the MT showed decreased Lactobacillus and increased Clostridium sensu strico 1 in the jejunum. In ceca, Megamonas, a genus containing butyrate-producing bacteria, was only present in birds administered the MT, and densities of this genus were increased in birds challenged with Cp. Metabolite profiles in cecal digesta were altered in birds administered the MT and challenged with the pathogen; 59 metabolites were differentially abundant following MT treatment, and the relative levels of short chain fatty acids, butyrate, valerate, and propionate, were decreased in birds with NE. Birds administered the MT and challenged with Cp showed evidence of enhanced restoration of intestinal barrier functions, including elevated mRNA of MUC2B, MUC13, and TJP1. Likewise, birds administered the MT exhibited higher mRNA of IL2, IL17A, and IL22 at 2-days post-inoculation with Cp, indicating that these birds were better immunologically equipped to respond to pathogen challenge. Collectively, study findings demonstrated that administering a MT containing a diverse mixture of microorganisms to day-old birds ameliorated NE in broilers by increasing bacterial diversity and promoting positive immune responses.

A stress-induced model of acute necrotic enteritis in broiler chickens using dietary corticosterone administration.

Mounting evidence indicates that stress can predispose chickens to disease. The objective of the current study was to develop a method that utilized physiological stress to predispose Ross 308 broiler chickens to acute necrotic enteritis (NE). Stress was mediated through the administration of the stress hormone, corticosterone. At 11 d posthatch (p.h.), corticosterone (20 mg kg-1) administration commenced. At 12 and 13 d p.h., birds were orally inoculated with a virulent strain of Clostridium perfringens, and at 14 d p.h., birds were euthanized. Birds administered corticosterone exhibited decreased weight gain, and birds co-challenged with C. perfringens and corticosterone were affected to a higher degree. Necrotic lesions were present in birds inoculated with C. perfringens (33%), but a substantially higher prevalence of birds treated with C. perfringens and corticosterone in combination exhibited lesions (100%). Clostridium perfringens densities were correlated with necrotic lesion and histopathologic scores. Both C. perfringens and corticosterone challenge altered mRNA immune responses in the small intestine. In this regard, birds infected with the pathogen showed higher relative mRNA concentrations of toll-like receptor 2A (TLR2A), transforming growth factor beta 2 (TGFß2), and inducible nitric oxide synthase (INOS). Birds co-challenged with C. perfringens and corticosterone showed hindered TLR2A mRNA expression. A reduction in TLR2A responses mediated by corticosterone administration suggests that the glucocorticoid suppresses immune stimulation in jejunal mucosa, which may be the underlying cause for the increased prevalence and intensity of disease observed in corticosterone treated birds. Overall, the corticosterone stress model resulted in levels of NE comparable to other models of NE that currently exist without the use of a co-infection agent. This model may facilitate the exploration of mechanisms of stress-induced NE, and the development of effective alternatives to antibiotics.

Comparative prevalence and diversity of Campylobacter jejuni strains in water and human beings over a 1-year period in southwestern Alberta, Canada.

Campylobacter jejuni was isolated from diarrheic people, river water (Oldman River watershed), wastewater, and drinking water over a 1-year period in southwestern Alberta (2008-2009). High rates of campylobacteriosis were observed during the study period (≥115 cases/100 K). Infections occurred throughout the year, with peaks in late summer and early autumn. Most infections occurred in people living in Lethbridge. Campylobacter jejuni was not isolated from municipal drinking water. In contrast, the bacterium was isolated from untreated and treated wastewater and river water (all sites). There were no correlations between C. jejuni recovery/detection from water and river flow rates, water turbidity, or fecal coliforms. Campylobacter jejuni recovery from water did not correspond to the peak periods of campylobacteriosis. The bacterium was most commonly isolated downstream of wastewater outfalls; waterfowl congregated at these sites, particularly during the winter months. A comparison of C. jejuni isolates from people and water revealed that most subtypes in water did not correspond to subtypes recovered from diarrheic people and were linked to waterfowl and other non-human animal sources. We conclude that waterborne C. jejuni did not contribute significantly to the high rates of campylobacteriosis observed in diarrheic people during the study period.

Rates of fluoroquinolone resistance in domestically acquired Campylobacter jejuni are increasing in people living within a model study location in Canada.

Antimicrobial resistance was evaluated in Campylobacter jejuni isolated from 1291 diarrheic people over a 15-year period (2004-2018) in southwestern Alberta, a model location in Canada with a high rate of campylobacteriosis. The prevalence of resistance to chloramphenicol, clindamycin, erythromycin, and gentamicin was low during the examination period (≤4.8%). Resistance to tetracycline remained consistently high (41.6%-65.1%), and resistance was primarily conferred by plasmid-borne tetO (96.2%). Resistance rates to ciprofloxacin and nalidixic acid increased substantially over the examination period, with a maximal fluoroquinolone resistance (FQR) prevalence of 28.9% in 2016. The majority of C. jejuni isolates resistant to ciprofloxacin (93.9%) contained a C257T single nucleotide polymorphism within the gyrA chromosomal gene. Follow up with infected people indicated that the observed increase in FQR was primarily due to domestically acquired infections. Moreover, the majority of FQ-resistant C. jejuni subtypes (82.6%) were endemic in Canada, primarily linked to cattle and chicken reservoirs; 18.4% of FQ-resistant isolates were assigned to three subtypes, predominantly associated with cattle. Study findings indicate the need to prioritize FQR monitoring in C. jejuni infections in Canada and to elucidate the dynamics of the emergence and transmission of resistant C. jejuni strains within and from cattle and chicken reservoirs.

Analysis of Campylobacter jejuni Subtype Distribution in the Chicken Broiler Production Continuum: a Longitudinal Examination To Identify Primary Contamination Points.

Significant knowledge gaps exist in our understanding of Campylobacter jejuni contamination of the poultry production continuum. Microbiological surveillance and genotypic characterization were undertaken on C. jejuni isolates longitudinally recovered from three poultry farms (weekly samples), the abattoir at which birds were processed, and at retail over a 542-day period in southwestern Alberta, Canada, as a model location. Subtypes were compared to concurrent isolates from diarrheic humans living in the study region. Barn outbreaks in broiler chickens occurred infrequently. Subtypes from colonized birds, including clinically relevant subtypes of C. jejuni, were recovered within barns and from subsequent production stages. When C. jejuni was detected in barns, most birds rapidly became colonized by a limited number of subtypes late in the cycle. However, the diversity of subtypes recovered from birds in the abattoir increased substantially. Moreover, birds deemed free of C. jejuni upon exit from the barn became contaminated within the abattoir environment, and a high prevalence of meat at retail was contaminated with C. jejuni, including subtypes that had not been previously observed in the barns. The observed increase in prevalence of contamination and diversity of C. jejuni subtypes along the chicken production continuum indicates that birds from a relatively small number of barns contaminate transport trucks and the abattoir with C. jejuni strains, which are collectively transferred to poultry within the abattoir and conveyed to and persist on retail products. We conclude that the abattoir was the primary contamination point of poultry by C. jejuni but only a subset of subtypes were a high risk to human beings.IMPORTANCE The longitudinal examination of Campylobacter jejuni subtypes throughout the broiler production continuum is required to determine transmission mechanisms and to identify potential reservoirs and the foodborne risk posed. We showed that a limited number of C. jejuni subtypes are responsible for infrequent outbreaks in broilers within production barns and that colonized birds from a small number of farms are introduced into the abattoir where a high prevalence of carcasses are subsequently contaminated with a diversity of subtypes, which are transferred onto poultry in retail settings. However, only a subset of strains on poultry was determined to be clinically relevant. The study findings showed that resolving C. jejuni at the subtype level is important to ascertain health risks, and the knowledge obtained in the study provides information to mitigate clinically relevant subtypes to reduce the burden of campylobacteriosis.

The absence of murine cathelicidin-related antimicrobial peptide impacts host responses enhancing Salmonella enterica serovar Typhimurium infection.

BACKGROUND: Cathelicidins are a class of antimicrobial peptide, and the murine cathelicidin-related antimicrobial peptide (mCRAMP) has been demonstrated in vitro to impair Salmonella enterica serovar Typhimurium proliferation. However, the impact of mCRAMP on host responses and the microbiota following S. Typhimurium infection has not been determined. In this study mCRAMP-/- and mCRAMP+/+ mice (± streptomycin) were orally inoculated with S. enterica serovar Typhimurium DT104 (SA +), and impacts on the host and enteric bacterial communities were temporally evaluated. RESULTS: Higher densities of the pathogen were observed in cecal digesta and associated with mucosa in SA+/mCRAMP-/- mice that were pretreated (ST+) and not pretreated (ST-) with streptomycin at 24 h post-inoculation (hpi). Both SA+/ST+/mCRAMP-/- and SA+/ST-/mCRAMP-/- mice were more susceptible to infection exhibiting greater histopathologic changes (e.g. epithelial injury, leukocyte infiltration, goblet cell loss) at 48 hpi. Correspondingly, immune responses in SA+/ST+/mCRAMP-/- and SA+/ST-/mCRAMP-/- mice were affected (e.g. Ifnγ, Kc, Inos, Il1ß, RegIIIγ). Systemic dissemination of the pathogen was characterized by metabolomics, and the liver metabolome was affected to a greater degree in SA+/ST+/mCRAMP-/- and SA+/ST-/mCRAMP-/- mice (e.g. taurine, cadaverine). Treatment-specific changes to the structure of the enteric microbiota were associated with infection and mCRAMP deficiency, with a higher abundance of Enterobacteriaceae and Veillonellaceae observed in infected null mice. The microbiota of mice that were administered the antibiotic and infected with Salmonella was dominated by Proteobacteria. CONCLUSION: The study findings showed that the absence of mCRAMP modulated both host responses and the enteric microbiota enhancing local and systemic infection by Salmonella Typhimurium.

Enhanced microbiological surveillance reveals that temporal case clusters contribute to the high rates of campylobacteriosis in a model agroecosystem.

Infections by pathogenic Campylobacter species were determined in diarrheic (n = 2,217) and non-diarrheic control (n = 104) people in Southwestern Alberta (SWA), Canada over a 1-year period using specialized and conventional isolation, and direct PCR. Overall, 9.9% of diarrheic individuals were positive for C. jejuni (9.1%), C. upsaliensis (0.6%), and C. coli (0.5%). No C. lari was detected. Four diarrheic individuals were co-infected with C. jejuni and C. coli, and four different individuals were co-infected with C. jejuni and C. upsaliensis. Two control individuals were positive for C. jejuni. Approximately 50% of stools containing C. jejuni and/or C. coli were deemed negative by conventional isolation. Direct PCR for C. jejuni was less effective than culture-based detection. Most C. jejuni infections occurred in people living in the urban centers, but the prevalence of the bacterium was lower in females than males living in urban locations, and both males and females living in rural locations. Although C. jejuni was detected throughout the year, a trend for higher infection rates was observed in the late spring to early fall with a peak in August. Forty-six C. jejuni subtype clusters were identified, including 44 temporal case clusters attributed to 28 subtype groupings. The majority of infections (70.3%) were linked to subtypes associated with beef cattle. We conclude that many occurrences of pathogenic Campylobacter species were not detected by the conventional laboratory methodology, and temporal case clusters of C. jejuni subtypes associated with cattle contribute to the high rates of campylobacteriosis in SWA.

Prevalence and diversity of waterborne Arcobacter butzleri in southwestern Alberta, Canada.

Arcobacter butzleri is a potential enteric pathogen to human beings, but its reservoirs and modes of transmission are largely unverified. Microbiological and molecular detection and subtyping techniques can facilitate surveillance of A. butzleri in hosts and environmental reservoirs. We isolated A. butzleri from 173 surface water samples (25.6%) and 81 treated wastewater samples (77.9%) collected in southwestern Alberta over a 1-year period. Arcobacter butzleri isolates (n = 500) were genotyped and compared to determine diversity of A. butzleri in southwestern Alberta. Culture methods affected the frequency of detection and genotype diversity of A. butzleri, and isolation comprehensiveness was different for surface waters and treated wastewaters. Detection of A. butzleri in the Oldman River Watershed corresponded with season, river flow rates, and fecal coliform densities. Arcobacter butzleri was detected most frequently in treated wastewater, in the Oldman River downstream from treated wastewater outfalls, and in tributaries near areas of intensive confined feeding operations. All sample sources possessed high genotype diversity, and A. butzleri isolates from treated wastewaters were genetically similar to isolates from the Oldman River downriver from treated wastewater outfall sites. In southwestern Alberta, municipal and agricultural activities contribute to the density and genotype diversity of A. butzleri in surface waters.

The prevalence of enteric RNA viruses in stools from diarrheic and non-diarrheic people in southwestern Alberta, Canada.

Southwestern Alberta is a region of Canada that has high rates of enteritis as well as high densities of livestock. The presence of enteric RNA viruses, specifically norovirus (NoV) GI, GII, GIII, GIV; sapovirus (SaV); rotavirus (RV); and astrovirus (AstV), was evaluated in stools from diarrheic (n = 2281) and non-diarrheic (n = 173) people over a 1-year period in 2008 and 2009. Diarrheic individuals lived in rural (46.6 %) and urban (53.4 %) settings and ranged in age from less than 1 month to 102 years, and the highest prevalence of infection in these individuals was in November. In all, viruses were detected in diarrheic stools from 388 individuals (17.0 %). NoV GII was the most frequently detected virus (8.0 %; n = 182) followed by SaV (4.3 %; n = 97), RV (2.0 %; n = 46), AstV (1.8 %; n = 42), NoV GI (0.9 %; n = 20), and NoV GIV (0.1 %; n = 1). Animal NoV GIII was never detected. The prevalence of mixed viral infections in diarrheic individuals was 2.8 % (n = 11). Children from 1 to 5 years of age accounted for the highest prevalence of positive stools, followed by the elderly individuals (≥70 years). Only NoV GII (1.2 %; n = 2) and SaV (1.2 %; n = 2) were detected in stools from non-diarrheic people. Sequence analysis of a subset of stools revealed homology to NoV, SaV and RV sequences from humans but not to strains from non-human animals. The results of this study do not support the hypothesis that viruses of animal origin have a significant impact on the occurrence of acute gastroenteritis caused by RNA enteric viruses in people living in southwestern Alberta.

Efficacy of wastewater treatment on Arcobacter butzleri density and strain diversity.

Arcobacter butzleri is a suspected waterborne enteric pathogen that is ubiquitous in the environment, but the degree to which wastewater treatment prevents entry of A. butzleri into environmental waters and the risks posed are not well established. Untreated and treated wastewater samples (n = 260) were collected weekly from the Lethbridge and Fort Macleod wastewater treatment facilities (the two major municipal inputs in southwestern Alberta, Canada) from May 2008 to April 2009. Untreated wastewaters contained high densities of A. butzleri and fecal coliform indicators, and densities at Lethbridge were typically higher than at Fort Macleod. Data indicated that A. butzleri and fecal coliform densities in wastewater were greatest in autumn and lowest in winter. Mechanical and biological treatment of wastewaters reduced but did not eliminate fecal coliform indicators or A. butzleri. At Lethbridge, UVB irradiation of mechanically and biologically treated wastewater further reduced densities of fecal coliform indicators. There was high A. butzleri genotype diversity in all sample sources, and survival during treatment was not strain-dependent. No genotype was dominant in any sample source, but 8.9% of genotypes were recurrent over time, and 4.4% of genotypes were detected at both wastewater treatment facilities. The current study demonstrates that viable A. butzleri are able to survive wastewater treatment, including UVB irradiation, which may lead to increased density and genetic diversity of this suspected pathogen in environmental waters via wastewater effluent discharge.

Comparative Detection and Quantification of Arcobacter butzleri in Stools from Diarrheic and Nondiarrheic People in Southwestern Alberta, Canada.

Arcobacter butzleri has been linked to enteric disease in humans, but its pathogenicity and epidemiology remain poorly understood. The lack of suitable detection methods is a major limitation. Using comparative genome analysis, we developed PCR primers for direct detection and quantification ofA. butzleri DNA in microbiologically complex matrices. These primers, along with existing molecular and culture-based methods, were used to detectA. butzleri and enteric pathogens in stools of diarrheic and nondiarrheic people (n= 1,596) living in southwestern Alberta, Canada, from May to November 2008. In addition, quantitative PCR was used to compare A. butzleridensities in diarrheic and nondiarrheic stools.Arcobacter butzleriwas detected more often by PCR (59.6%) than by isolation methods (0.8%). Comparison by PCR-based detection found no difference in the prevalence ofA. butzleri between diarrheic (56.7%) and nondiarrheic (45.5%) individuals. Rates of detection in diarrheic stools peaked in June (71.1%) and October (68.7%), but there was no statistically significant correlation between the presence ofA. butzleri and patient age, sex, or place of habitation. Densities ofA. butzleriDNA in diarrheic stools (1.6 ± 0.59 log10 copies mg(-1)) were higher (P= 0.007) than in nondiarrheic stools (1.3 ± 0.63 log10copies mg(-1)). Of the 892 diarrheic samples that were positive for A. butzleri, 74.1% were not positive for other bacterial and/or viral pathogens. The current study supports previous work suggesting that A. butzleri pathogenicity is strain specific and/or dependent on other factors, such as the level of host resistance.

Association of age and gender with Torque teno virus detection in stools from diarrheic and non-diarrheic people.

BACKGROUND: Torque teno virus (TTV) is a small virus belongs to Anelloviridea family. TTV is a disease orphan virus but it has often been associated with a variety of pathologies and co-infections. TTV was recently identified as an infectious agent that could potentially be involved in cases of acute enteritis. OBJECTIVES: To ascertain the presence of TTV in stools from diarrheic and not diarrheic people, and to investigate an association between infection, and patient age and gender. STUDY DESIGN: Stool samples from people exhibiting signs of enteritis (954) and from non-diarrheic individuals (76) were collected in the former Chinook Health Region (CHR) in Southwestern Alberta, Canada from May 2008 to April 2009. Viral genetic material was extracted, and detection and quantification of TTV were carried out by real-time PCR. The presence of other viral and bacterial enteric pathogens was also investigated. RESULTS: More (P<0.001) diarrheic people (38.8%) tested positive for TTV DNA than non-diarrheic individuals (18.4%). Furthermore, viral load was greater (P<0.001) in stools from diarrheic (2.0×10(7)copies/g) than non-diarrheic (2.0×10(3)copies/g) people. TTV DNA was detected most often in diarrheic individuals that were 0-5 (57.3%) and greater than 81 (59.0%) years of age. Combined across age, the prevalence of TTV was higher among men than women (P=0.003). Co-infections with other enteric pathogens were observed. CONCLUSIONS: This study revealed a significant association between TTV prevalence and viral load, and enteritis. Also, TTV prevalence was significantly higher in the very young and elderly suggesting that immunological status is important.

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

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.