MICROBIOLOGICAL AND EPIDEMIOLOGICAL INVESTIGATIONS AT THE VLA

Transcription

1 CAMPYLOBACTER IN BROILERS IN UK: MICROBIOLOGICAL AND EPIDEMIOLOGICAL INVESTIGATIONS AT THE VLA J. Rodgers 1, L. Powell 2, F. Clifton-Hadley 1 and A. Vidal 1 1 Dept of Food and Environmental Safety 2 Centre for Epidemiology and Risk Analysis Veterinary Laboratories Agency - Weybridge, New Haw, Addlestone, United Kingdom. j.rodgers@vla.defra.gsi.gov.uk 1

2 CAMPYLOBACTER AND VLA (VETERINARY LABORATORIES AGENCY) Campylobacter, a major public health problem in EU 2, Campylobacteriosis cases per annum EU demand for monitoring Campylobacter in food production EU baseline survey of broilers in 28 performed at VLA Protect public health by control of Campylobacter in food chain VLA objective to safeguard veterinary and public health through surveillance and research Government funded research projects Collaboration with Industry, Institutes and Universities 2

3 Towards risk based control of Campylobacter Crate colonisation studies Animal models RESEARCH ACTIVITY AT VLA Update the UK Risk assessment model Risk factor analysis Seasonality, thinning EU Baseline survey 3 year National prevalence survey Isolate archive (7) project links MLST, AMR Method development and validation Field epidemiology studies Exploitation of Campylobacter MLST databases Oxford University 3

4 CHRO 29 Campylobacter in broilers: Results from a UK National Prevalence Survey carried out in 27 Laura Powell 1, Felicity Clifton-Hadley 2, Joanna Lawes 1, John Rodgers 2, Ana Vidal 2 Comparative sampling strategies and test combinations for detection and quantifications of Campylobacter in broiler flocks at the abattoir Ana Vidal*, John Rodgers, Felicity Clifton-Hadley, Laura Powell & Mark Arnold The effect of time between collection and testing and culture methodology on the detection of Campylobacter in broiler caecal contents John Rodgers 1, Clara Marin 2, Felicity Clifton-Hadley 1, Ana Vidal 1 Comparison of a real-time PCR method with culture for the detection of C. jejuni and C. coli in UK broilers flocks John Rodgers*, Luke Randall, Ana Vidal Sampling strategies and laboratory methods for Campylobacter detection in broiler flocks at primary production Ana Vidal*, John Rodgers, Felicity Clifton-Hadley, Laura Powell & Mark Arnold Genetic diversity of C. jejuni from conventional broiler flocks by MLST: effect of sampling strategies and laboratory methodologies Ana Vidal 1 *, Frances Colles 2, John Rodgers 1, Felicity Clifton-Hadley 1, Martin Maiden 2 & Laura Powell 1 1 Department of Food and Environmental Safety, Veterinary Laboratories Agency, New Haw, UK 2 University of Oxford, South Parks, Oxford, UK 4

5 NATIONAL PREVALENCE SURVEY DESIGN (27 DATA) Survey design and sampling based on EU specification Abattoir (1 caeca per batch) Randomised, weighted, stratified Direct culture mccda and enrichment 37 abattoirs recruited 28 selected to sample 412 batches sampled 374 eligible 38 ineligible (89% >8hrs) Abattoir Batch Day 5

6 NATIONAL PREVALENCE SURVEY RESULTS 27 Overall prevalence = 82% (37/374) Prevalence by age group (days) C. jejuni C. coli < plus

7 Prevalence (%) NATIONAL PREVALENCE SURVEY RESULTS 27 Campylobacter prevalence by month (n = 374) Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec C.coli C.jejuni Prevalence varied by month Lowest April (63.3%) Highest August (1%) Species detected varied by month C. coli low in Feb / high in June C. jejuni low in Sept / high in August 7

8 NATIONAL PREVALENCE SURVEY RESULTS 27 Campylobacter prevalence by month, stratified by thinning status, (conventional flocks) n = Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec All batches First batch removed Previously depopulated 8

9 NATIONAL PREVALENCE SURVEY RESULTS 27 Exposure Thinning status Previously depopulated* Odds Ratio CI 95% p-value Age group (days) Season Summer Mortality at 72 hours before slaughter Autumn % *Previously depopulated (Thinning status): The thinning status of batches sampled were recorded as first batch removed or previously depopulated. Batches recorded as previously depopulated were an a priori risk factor Baseline groups: Thinning status first batch removed, Age group <35 days, Season - Winter, Mortality at 72 hours before slaughter < 2.21% Final model: Thinning status, age group, season, mortality at 72 hours, company (clustered on Farm ID) 9

10 PCR DETECTION FROM PREVALENCE SURVEY SAMPLES PCR why? Rapid, flexible, detect non-cultivable organisms Species identification DNA extraction process Detection of unviable organisms Existing real-time PCR (Best et al., 23) mapa gene for C. jejuni / ceue gene for C. coli Developed for broiler caecal contents DNA extraction Internal amplification control detected inhibition in 12 of 425 samples Detection limit assessed 1 5 CFU/g 1

11 PCR DETECTION FROM PREVALENCE SURVEY SAMPLES PCR versus culture in 413 samples Relative to culture with enrichment Sensitivity = 9.4% Specificity = 87.5% False negatives by PCR Low numbers in sample (<1 5 cfu/g) False negatives by culture Cell present in high numbers (> 1 5 cfu/g) Low viability of bacteria, stress, media More common in direct culture (3 samples) PCR DC+EN

12 PCR DETECTION FROM PREVALENCE SURVEY SAMPLES EU method (One colony is speciated and reported) Most batches identified with C. coli by EU are mixed infection C. jejuni is present in most positive batches (93%) C. coli present in (35.5%) PCR detection of species in flocks positive by direct culture (DC) C.jejuni by DC n=231 C.coli by DC n=85 PCR C. jejuni PCR coli PCR C. jejuni/coli PCR negative 12

13 DETECTION OF CAMPYLOBACTER ON BROILER FARMS 2 broiler farms 2 houses per farm 4 broiler flocks End of rearing period days July-November 28 13

14 DETECTION OF CAMPYLOBACTER ON BROILER FARMS Sampling strategies 1. BOOT SWABS 2. FAECAL DROPPINGS 3. CAECAL CONTENTS 14

15 Number of positive samples DETECTION OF CAMPYLOBACTER ON BROILER FARMS Positive flocks by sample type and by DC vs EN Sample Boot/BPW Boot/CB Boot/EX Boot/MRD Char-swab caeca 8 NOT contaminated 18 FULLY contaminated 14 PARTIALLY contaminated 15

16 DETECTION OF CAMPYLOBACTER ON BROILER FARMS C. jejuni C. coli Methods best for C. jejuni detection Boot swabs more sensitive than caeca or faecal droppings for C. jejuni Enrichment increase sensitivity in most cases 16

17 DETECTION OF CAMPYLOBACTER ON BROILER FARMS CLONAL COMPLEXES Clonal complexes 15 C. COMPLEXES 8 Complexes - > 75% 5 unassigned 19.% Clonal complexes ST-573 complex No value ST-21 complex ST-67 complex ST-661 complex ST-354 complex ST-45 complex ST-134 complex ST-353 complex ST-574 complex ST-52 complex ST-48 complex ST-22 complex ST-257 complex ST-443 complex 573 complex 2.4% 21 complex 13.2 % 67 complex % 661 complex - 7.9% 354 complex - 7.7% 45 complex - 7.2% 134 complex 5.5% 353 complex - 4.5% Others 24.8% 573 complex associated with human and chicken. UK. 354 complex associated with human, chicken, and farm. WW. 17

18 No of isolates DETECTION OF CAMPYLOBACTER ON BROILER FARMS ST-complexes by sample type STs-complexes clonal_complex_1 ST-661 complex ST-67 complex ST-574 complex ST-573 complex ST-52 complex ST-48 complex ST-464 ST-45 complex ST-449 ST-443 complex ST-3967 ST-3923 ST-3573 ST-354 complex ST-353 complex ST-257 complex ST-22 complex ST-21 complex ST-134 complex Sample Boot/BPW Boot/CB Boot/EX Boot/MRD caeca Char-swab 18

19 SUMMARY National prevalence survey 27 Prevalence Campylobacter 82% Campylobacter prevalence 82% in UK broiler flocks Increased prevalence associated with summer, thinning, age C. jejuni most prevalent species followed by C. coli PCR detection of Campylobacter from caecal content Compares well with culture can identify mixed infections Detection of Campylobacter at the farm level Boot swabs a sensitive and convenient sample MLST typing of Campylobacter at farm level Types associated with human infection recovered Common types recovered by all sample types or media 19

20 Thanks to DEFRA & FSA UK Poultry Industry MHS, AFBINI, DARDNI CERA team (VLA) FES team (VLA) Oxford University 2