Prevalence of Salmonella spp. in environmental samples from table egg barns in Alberta.

Some Salmonella spp. are zoonotic, a frequent cause of foodborne illness in Canada, and known to infect humans through contaminated poultry and poultry products. Certain serotypes of Salmonella spp. have been demonstrated to be vertically transmitted from hen to egg. The incidence of Salmonella spp. isolation in the flock has been correlated to its isolation from the environment. Twenty-one producers were enrolled in this study to examine the occurrence of Salmonella spp. in 48 table egg layer flocks housed in 35 barns in Alberta. The purpose of this study was to: (i) identify Salmonella serotypes isolated from the environment of table egg layer facilities in Alberta and (ii) record the prevalence of Salmonella spp. across eight defined environmental sampling points. Salmonella spp. were isolated from the environment of 20/35 barns representing 29/48 flocks. The most common serotypes isolated were S. Heidelberg, S. Kentucky and S. Mbandaka. The order of most to least contaminated sample location was manure belts (54.1%), feeders (47.9%), feed motors (45.8%), egg belts and walls (41.7%), fans (35.0%), cage bottoms (31.3%) and lobbies (27.1%). Salmonella spp. were isolated from 7/7 barns post cleaning and disinfection, demonstrating the persistence of this organism in the environment and the need for effective eradication protocols.

Association of Mycobacterium avium subspecies paratuberculosis with Crohn Disease in pediatric patients.

OBJECTIVES: The aim of the present study was to determine the prevalence of Mycobacterium avium subsp paratuberculosis (MAP) DNA in intestinal biopsies from pediatric patients with granulomatous Crohn disease (CD) or ulcerative colitis (UC), and matched control subjects without inflammatory bowel disease (IBD). PATIENTS AND METHODS: DNA was extracted from formalin-fixed paraffin-embedded colonic and ileal biopsies from patients with CD (n = 22) or UC (n = 20), and from controls without IBD (n = 21). IS900 nested polymerase chain reaction was performed in triplicate to determine the presence of MAP-specific DNA. RESULTS: In mucosal biopsies from terminal ileum, IS900 amplicons were detected in 1 of 19 (5.2%) control subjects, 1 of 20 (5%) patients with UC, and 7 of 20 (35%) patients with CD (P < 0.05 vs controls, odds ratio 9.6). In colonic biopsies, IS900 amplicons were detected in 0 of 19 control subjects, 1 of 19 (5.2%) patients with UC, and 5 of 19 (26.3%) patients with CD (P < 0.05 vs controls, odds ratio 14.8). In patients with CD, there was no correlation between disease activity and the presence of IS900. CONCLUSIONS: Our technique enabled sensitive and specific detection of MAP DNA in archival endoscopic biopsy specimens. Although MAP-specific DNA can be detected in about 5% of intestinal biopsies from children with UC or controls without IBD, its presence was significantly associated with pediatric granulomatous CD, being particularly prevalent in ileal tissue. This easily defined clinical subset of patients may be useful for additional studies to determine the role of MAP in CD.

Multi-provincial Salmonellosis Outbreak Related to Newly Hatched Chicks and Poults: A Genomics Perspective.

BACKGROUND: A multi-provincial outbreak of Salmonella enterica serovar Enteritidis was linked to newly hatched chicks and poults from a single hatchery during the spring of 2015. In total, there were 61 human cases that were epidemiologically confirmed to be linked to the chicks and poults and the outbreak was deemed to have ended in the summer of 2015. METHODS: PulseNet Canada, in coordination with the affected provinces, used genome sequencing of human and agricultural Salmonella Enteritidis isolates to aid in the epidemiological investigation, while also using traditional typing methods such as phagetyping and pulsed-field gel electrophoresis (PFGE). RESULTS: All human outbreak cases, except one, were Phage Type (PT) 13a. Single nucleotide variant analysis (SNV) was able to provide a level of resolution commensurate with the results of the epidemiological investigation. SNV analysis was also able to separate PT13a outbreak-related isolates from isolates not linked to chicks or poults, while clustering some non-PT13a agricultural strains with the outbreak cluster. CONCLUSIONS: Based on conventional typing methods (phagetyping or PFGE), clinical and agricultural PT13a SE isolates would have been considered as part of a related cluster. In contrast, phagetyping would have led to the exclusion of several non- PT13a strains that clustered with the outbreak isolates using the genome sequence data. This study demonstrates the improved resolution of genome sequence analysis for coordinated surveillance and source attribution of both human and agricultural SE isolates.

Evaluation of detection methods for screening meat and poultry products for the presence of foodborne pathogens.

Rapid and molecular technologies such as enzyme-linked immunosorbent assay (ELISA), PCR, and lateral flow immunoprecipitation can reduce the time and labor involved in screening food products for the presence of pathogens. These technologies were compared with conventional culture methodology for the detection of Salmonella, Campylobacter, Listeria, and Escherichia coli O157:H7 inoculated in raw and processed meat and poultry products. Recommended protocols were modified so that the same enrichment broths used in the culture methods were also used in the ELISA, PCR, and lateral flow immunoprecipitation assays. The percent agreement between the rapid technologies and culture methods ranged from 80 to 100% depending on the pathogen detected and the method used. ELISA, PCR, and lateral flow immunoprecipitation all performed well, with no statistical difference, compared with the culture method for the detection of E. coli O157:H7. ELISA performed better for the detection of Salmonella, with sensitivity and specificity rates of 100%. PCR performed better for the detection of Campylobacter jejuni, with 100% agreement to the culture method. PCR was highly sensitive for the detection of all the foodborne pathogens tested except Listeria monocytogenes. Although the lateral flow immunoprecipitation tests were statistically different from the culture methods for Salmonella and Listeria because of false-positive results, the tests did not produce any false negatives, indicating that this method would be suitable for screening meat and poultry products for these pathogens.

Verification of the level of Microbiological Control for the Slaughter and Cooling Processes of Beef Carcass Production at a High-line-Speed Abattoir.

Methods are described which were used to verify the microbiological adequacy of the processes of production and chilling of carcasses at a high-line-speed abattoir. Ten excision samples (5 by 5 by 0.2 cm) were taken from each of 16 to 20 carcasses for each evaluation of these processes. Twelve monthly evaluations were made for the slaughter of steers, heifers, and cows and additional evaluations for each of the slaughter of cows and the chill process of carcasses. The ranges of the estimated mean log10 most probable number of growth units per square centimeter (LMPN, for 236 carcasses) and Escherichia coli per square centimeter (LEC, for 240 carcasses) enumerated by hydrophobic-grid membrane filter technology for the 12 monthly evaluations of the slaughter floor were 1.11 to 1.62 (LMPN) for single samples and 0.20 to 0.65 (LEC) for pooled samples. Based on a published advisory scale for the slaughter floor the aerobic bacterial counts reflect a cleanliness level of "excellent" to "good." For single evaluations of cow carcasses at the end of slaughter and of chilled carcasses the mean LMPN was 1.78 ("good") and 1.40 respectively. From pooled samples of each of the 236 steer, heifer, and cow carcasses the pathogen E. coli O157:H7 was identified by polymerase chain reaction on one carcass whereas Listeria monocytogenes was identified on 14 carcasses. Verocytoxigenic E. coli (6 isolates) and L. monocytogenes were not isolated from the same carcasses. These low isolation rates dictate a large sample size and therefore these pathogens are excluded from use to routinely verify the workings of hazard analyses and critical control point (HACCP) systems for beef slaughter processes in Alberta. Alternatively the use of aerobic bacterial counts to directly measure cleanliness or of E. coli counts to indirectly measure fecal contamination appears to be more practical than the use of specific pathogen counts for regulatory agencies to verify the workings of quality control programs, including HACCP systems.