Risk factors for infection with<i>Campylobacter jejuni flaA</i>genotypes

Unicomb, Leanne; O'Reilly, Lyn C.; Kirk, Martyn; Stafford, Russell; Smith, Helen; Becker, Niels G.; Patel, Mahomed; Gilbert, Gwendolyn L.

doi:10.1017/s0950268807000246

Cited by 10 publications

(5 citation statements)

References 40 publications

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“…Previous case-control studies have identi ed PPI use as a risk factor contributing to human Campylobacter infection [34,35,46,47]. Increases in campylobacteriosis incidence may also be associated with increased PPI use [48].…”

Section: Discussionmentioning

confidence: 99%

Risk Factors for Campylobacteriosis in Australia: Outcomes of a 2018–2019 Case-Control Study

Cribb

Varrone

Wallace

et al. 2022

Preprint

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Background We aimed to identify risk factors for sporadic campylobacteriosis in Australia, and to compare these for Campylobacter jejuni and Campylobacter coli infections. Methods In a multi-jurisdictional case-control study, we recruited culture-confirmed cases of campylobacteriosis reported to state and territory health departments from February 2018 through October 2019. We recruited controls from notified influenza cases in the previous 12 months that were frequency matched to cases by age group, sex, and location. Campylobacter isolates were confirmed to species level by public health laboratories using molecular methods. We conducted backward stepwise multivariable logistic regression to identify significant risk factors. Results We recruited 571 cases of campylobacteriosis (422 C. jejuni and 84 C. coli) and 586 controls. Important risk factors for campylobacteriosis included eating undercooked chicken (adjusted odds ratio [aOR] 70, 95% CI 13–1296) or cooked chicken (aOR 1.7, 95% CI 1.1–2.8), owning a pet dog aged < 6 months (aOR 6.4, 95% CI 3.4–12), and the regular use of proton-pump inhibitors in the four weeks prior to illness (aOR 2.8, 95% CI 1.9–4.3). Risk factors remained similar when analysed specifically for C. jejuni infection. Unique risks for C. coli infection included eating chicken pâté (aOR 6.1, 95% CI 1.5–25) and delicatessen meats (aOR 1.8, 95% CI 1.0–3.3). Eating any chicken carried a high population attributable fraction for campylobacteriosis of 42% (95% CI 13–68), while the attributable fraction for proton-pump inhibitors was 13% (95% CI 8.3–18) and owning a pet dog aged < 6 months was 9.6% (95% CI 6.5–13). The population attributable fractions for these variables were similar when analysed by campylobacter species. Eating delicatessen meats was attributed to 31% (95% CI 0.0–54) of cases for C. coli and eating chicken pâté was attributed to 6.0% (95% CI 0.0–11). Conclusions The main risk factor for campylobacteriosis in Australia is consumption of chicken meat. However, contact with young pet dogs may also be an important source of infection. Proton-pump inhibitors are likely to increase vulnerability to infection.

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Section: Discussionmentioning

confidence: 99%

Risk Factors for Campylobacteriosis in Australia: Outcomes of a 2018–2019 Case-Control Study

Cribb

Varrone

Wallace

et al. 2022

Preprint

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“…The flagellin gene has been a well-accepted marker for Campylobacter genotyping for over 2 decades (4,16,18,19,22,25,32). In this study we have developed a genotyping method based on flaA interrogation using HRM analysis.…”

Section: Discussionmentioning

confidence: 99%

Campylobacter jejuni and Campylobacter coli Genotyping by High-Resolution Melting Analysis of a flaA Fragment

Merchant-Patel

Blackall²,

Templeton³

et al. 2010

Appl Environ Microbiol

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The highly variable flagellin-encoding flaA gene has long been used for genotyping Campylobacter jejuni and Campylobacter coli. High-resolution melting (HRM) analysis is emerging as an efficient and robust method for discriminating DNA sequence variants. The objective of this study was to apply HRM analysis to flaA-based genotyping. The initial aim was to identify a suitable flaA fragment. It was found that the PCR primers commonly used to amplify the flaA short variable repeat (SVR) yielded a mixed PCR product unsuitable for HRM analysis. However, a PCR primer set composed of the upstream primer used to amplify the fragment used for flaA restriction fragment length polymorphism (RFLP) analysis and the downstream primer used for flaA SVR amplification generated a very pure PCR product, and this primer set was used for the remainder of the study. Eighty-seven C. jejuni and 15 C. coli isolates were analyzed by flaA HRM and also partial flaA sequencing. There were 47 flaA sequence variants, and all were resolved by HRM analysis. The isolates used had previously also been genotyped using single-nucleotide polymorphisms (SNPs), binary markers, CRISPR HRM, and flaA RFLP. flaA HRM analysis provided resolving power multiplicative to the SNPs, binary markers, and CRISPR HRM and largely concordant with the flaA RFLP. It was concluded that HRM analysis is a promising approach to genotyping based on highly variable genes.Campylobacter jejuni and Campylobacter coli are the most common causes of human bacterial gastroenteritis in industrialized countries (21). The flagellin-encoding genes flaA and flaB share 95% sequence homology and are arranged in tandem (9,20). While flaA gene expression appears critical for motility, colonization, and pathogenesis, this is not the case for flaB, which is thought to be a largely nonfunctional reservoir of genetic variation that can increase the diversity of flaA by recombination and so assist the cell in evading host immune responses (1,7,8,28).The flaA gene is commonly used for typing C. jejuni and C. coli. Two methods have gained wide acceptance: flaA restriction fragment length polymorphism (RFLP) (19) and flaA short variable region (SVR) sequencing (16). The flaA RFLP technique involves PCR amplification of the entire flaA gene followed by RFLP of the PCR product (19). Sequencing the SVR of the flaA gene was developed as a more streamlined and portable alternative to flaA RFLP protocols (16), and sequence variants are compiled at a central website (http://pubmlst.org/campylobacter /flaA/) (10). While both of these methods are very effective, they have several disadvantages: the RFLP approach is multistep, because the PCR product must be cleaved with a restriction enzyme, and the fragments must be subsequently resolved by electrophoresis (33). Also, there are many changes in the sequence that will not alter the sizes of the restriction fragments. SVR sequencing is also multistep; the targeted region is small, which limits resolving power; and DNA sequencing requires expensive equipment ...

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“…For example, the identification of host-associated genetic variation [24] and the extent to which this segregates by host (host generalist and specialist genotypes) [25][26][27], means that human infection can be attributed to a specific reservoir source, when there is no human-to-human transmission [24,25,[27][28][29]. Furthermore, in some cases it is possible to link particular genotypes to common disease sequelae [30][31][32] or severe infections [33][34][35], and identify locally [36][37][38] and globally distributed strains [39,40].…”

Section: Introductionmentioning

confidence: 99%

Genomic epidemiology of Campylobacter jejuni associated with asymptomatic pediatric infection in the Peruvian Amazon

et al. 2020

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Campylobacter is the leading bacterial cause of gastroenteritis worldwide and its incidence is especially high in low-and middle-income countries (LMIC). Disease epidemiology in LMICs is different compared to high income countries like the USA or in Europe. Children in LMICs commonly have repeated and chronic infections even in the absence of symptoms, which can lead to deficits in early childhood development. In this study, we sequenced and characterized C. jejuni (n = 62) from a longitudinal cohort study of children under the age of 5 with and without diarrheal symptoms, and contextualized them within a global C. jejuni genome collection. Epidemiological differences in disease presentation were reflected in the genomes, specifically by the absence of some of the most common global diseasecausing lineages. As in many other countries, poultry-associated strains were likely a major source of human infection but almost half of local disease cases (15 of 31) were attributable to genotypes that are rare outside of Peru. Asymptomatic infection was not limited to a single (or few) human adapted lineages but resulted from phylogenetically divergent strains suggesting an important role for host factors in the cryptic epidemiology of campylobacteriosis in LMICs.

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Risk factors for infection withCampylobacter jejuni flaAgenotypes

Cited by 10 publications

References 40 publications

Risk Factors for Campylobacteriosis in Australia: Outcomes of a 2018–2019 Case-Control Study

Risk Factors for Campylobacteriosis in Australia: Outcomes of a 2018–2019 Case-Control Study

Campylobacter jejuni and Campylobacter coli Genotyping by High-Resolution Melting Analysis of a flaA Fragment

Genomic epidemiology of Campylobacter jejuni associated with asymptomatic pediatric infection in the Peruvian Amazon

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