This thesis is an investigation of human campylobacteriosis and Campylobacter from retail chicken in two Ontario health units. The objectives were to investigate the symptoms, severity, antimicrobial use (AMU), antimicrobial resistance (AMR), and duration of illness (DI) in clinical campylobacteriosis, the prevalence and AMR of Campylobacter from contaminated retail chicken, and the relationship between clinical and chicken Campylobacter isolates based on Comparative Genomic Fingerprinting (CGF). In the participating health units, campylobacteriosis case data were collected and retail chicken was sampled from randomly selected stores. Campylobacter isolates from clinical cases and chicken were antimicrobial susceptibility tested and CGF typed. A Cox proportional hazard model was used to investigate the DI in campylobacteriosis. Logistic regression models were used to explore the relationship between clinical and chicken CGF types. Of 250 cases, 52% reported taking antimicrobials for their campylobacteriosis. In 124 cases with accompanying isolate and AMR information, 6 (4.8%) and 2 (1.6%) isolates were resistant to ciprofloxacin and erythromycin, respectively. In 749 chicken isolates, 14 (1.9%) and 25 (3.3%) isolates were resistant to ciprofloxacin and erythromycin, respectively. No isolates were resistant to both antimicrobials. While the low prevalence of AMR to ciprofloxacin and erythromycin was encouraging, the high proportion of cases treated with antimicrobials was concerning and efforts should be made to reduce unnecessary treatment. The Cox model identified that use of a macrolide for less than the recommended duration, use of ciprofloxacin for the recommended duration, and use of other antimicrobials, were factors associated with decreased DI. The impact of AMU was consistent regardless of when in the course of illness it began. The CGF results were available from 115 clinical and 718 chicken isolates. A Campylobacter CGF reference database was used to identify CGF types that comprised at least 80% of isolates from chicken, based on 90% fingerprint similarity (CA90). Isolates from urban cases were significantly more likely than rural cases to be CA90. In Canada, the majority of campylobacteriosis cases are urban dwellers. Therefore, the association between urban cases and CA90 emphasizes the importance of Campylobacter from retail chicken on public health.

No description available.

The control of foodborne pathogens especially Salmonella and Campylobacter are of great concern to the commercial poultry industry. The control of these pathogens could be essential in the reduction of foodborne illness and deaths related to eggs and poultry meat. Previous studies have found that the presence or disappearance of Salmonella or Campylobacter is linked to various environmental and management-based factors, of which include vaccines used in the industry. Presently, we evaluated the effect of the infectious bronchitis virus (IBV) vaccine on the incidence of Salmonella or Campylobacter prevalence in broiler chicks. In the current study, a high vaccine dosage of IBV vaccine was associated with an increase the prevalence of Campylobacter during the first two weeks of age. Although in a previous study a high vaccine dose of IBV was linked in to increased prevalence of Salmonella, this was not seen in our study. In a subsequent trial, we also evaluated the potential cross-protection against three Salmonella serotypes of two-previously formulated vaccines when used in various dosage combinations. The combination vaccine was effective in reducing shedding of S. Enteritidis however reduction of S. Typhimurium and S. Hadar were not seen consistently. The vaccines were also shown to not significantly affect the body weights of the birds. Vaccines have been an essential component in the control of diseases within flocks in the commercial poultry industry. Ensuring the uniform application of IBV vaccine could help prevent and/or reduce the prevalence of Campylobacter in broiler flocks. The combination vaccine was effective against one serotype of Salmonella but further trials are needed to complete evaluate its potential as a vaccine that could be used in the poultry industry.

In a previous study, twenty-five flaA types were detected among 200 Campylobacter jejuni isolates obtained from clinical and poultry meat sources. The most common flaA type detected among poultry isolates was flaA-3 at a frequency of 23%. In contrast, flaA-3 constituted 5% of the clinical isolates. FlaA-15 was detected most frequently among clinical isolates (31%) but rarely among poultry isolates (5%). Purchasers of poultry meat were therefore commonly exposed to flaA-3 yet most of the human infections were due to flaA type 15. The prevalence of different flaA types in poultry and humans might have been due to: FlaA-15 was more virulent for humans than flaA-3 (infection more likely to result). There were more C. jejuni flaA-15 cells on poultry meat (dose effect). Better survival of flaA-15 cells when freeze/thawed or when stored at +4�C (survival in kitchen). Ecological performance of flaA-3 strains in chicken gut better than that of flaA-15 (more flaA -3 cells in gut therefore greater chance of carcass contamination)? Eleven strains representing flaA types 3, 13, and 15 were tested for their ability to invade cultured human epithelial cells (HEp-2). Invasiveness was considered to reflect virulence. FlaA-15 isolates were more invasive in comparison to flaA-3 and flaA-13 isolates (p<0.0001). Washings from chicken portions were cultured to enumerate Campylobacter cells present on the meat. C. jejuni isolates were flaA typed and the numbers were related to FlaA type. A correlation was not detected. The eleven representative strains were used to inoculate 1 cm� sections of chicken skin which were stored at -20�C or +4�C over a five day period. The samples stored at -20�C were thawed and held either overnight at 25�C, overnight at +4�C or for thirty minutes at 25�C. The numbers of viable Campylobacter cells on the sections were determined. Survival ability differed from strain to strain but was not associated with flaA type. The most invasive C. jejuni strain (T1016; flaA-15) and the least invasive strain (Pstau; flaA-3) were assessed for their ability to colonise the intestinal tract of one-day-old chicks. The dynamics of colonisation, after inoculation of the birds with pure cultures or with mixtures, was monitored by real-time quantitative PCR. Strain-specific primers based on the variable region of the nucleotide base sequence of flaA genes were derived for this work. This enabled the individual strains to be enumerated in gut contents from colonized chickens. Both strains could colonise the chick intestinal tract but C. jejuni strain T1016 (flaA-15) could competitively exclude PStau (flaA-3). It was concluded that the higher prevalence of flaA-15 strains among the clinical isolates was due to its higher virulence for humans. In other words, despite a low prevalence of flaA-15 on poultry meat, infection was more likely to result when C. jejuni flaA-15 cells were consumed.

Infection by Campylobacter is the most notified gastrointestinal disease in New Zealand. Reliable recovery and identification of campylobacters is challenging. Improved and validated methods are needed to increase the power of subtyping and epidemiological studies to trace the sources and transmission routes of Campylobacter. An enrichment-PCR method for the isolation and detection of C. jejuni and C. coli was developed and sensitivity levels determined in 13 environmental matrices, including animal faeces, food and water. Less than ten cells per sample of either C. jejuni or C. coli could be detected, except for rabbit faeces where the minimum number of cells detected per sample was greater than ten cells for C. coli (range 3-32 cells). The sensitivity of the method was comparable to that determined for the conventional methods in the same matrices. Application of the method to retail chicken carcasses (n =204) determined a prevalence of 27.5% C. jejuni and 1% C. coli. River water assays (n = 293) found 55.3% of samples to contain C. jejuni and 4.1% C. coli. Furthermore, the enrichment-PCR assay was shown to identify up to three subtypes in individual water samples. It was proposed that the identification of non-dominant subtypes carried by a chicken carcass may aid the identification of subtypes implicated in human cases of campylobacteriosis. An average of twenty-three C. jejuni isolates from each of ten retail chicken carcass were subtyped by PFGE using the two restriction enzymes SmaI and KpnI. Fifteen subtypes, in total, were identified from the ten carcasses. One subtype was identified on three carcasses. Five carcasses carried a single subtype, three carcasses carried two subtypes each and two carcasses carried three subtypes each. Some of the subtypes carried by an individual carcass were shown to be clonally related raising the question of in vivo recombination events during host passage. Comparison of C. jejuni subtypes from chickens with those isolated from human clinical cases revealed three of the fifteen subtypes correlated with those from human cases. None of the minority subtypes were identified in human case isolate data, suggesting that the lack of identification of non-dominant subtypes from chicken carcasses may not hinder the investigation of campylobacteriosis outbreaks.

Thesis (Ph. D. microbiology)--Washington State University, May 2008. / Includes bibliographical references.

Zugl.: Berlin, Freie Universiẗat, Diss., 2008.

Thesis (M.S. in microbiology)--Washington State University, May 2009. / Title from PDF title page (viewed on Apr. 12, 2010). "School of Molecular Biosciences." Includes bibliographical references.

Thesis (M.S. in microbiology)--Washington State University, May 2010. / Title from PDF title page (viewed on June 16, 2010). "School of Molecular Biosciences." Includes bibliographical references.

Thesis (M.S. in microbiology)--Washington State University, May 2007. / Includes bibliographical references (p. 32-37).