Salmonellosis
OIE Reference Laboratory Reports
Activities in 2010
Name of disease (or topic) for which you are a designated OIE Reference Laboratory: / SalmonellosisAddress of laboratory / Veterinary Laboratories Agency Weybridge
Woodham Lane, New Haw, Addlestone
Surrey KT15 3NB
UNITED KINGDOM
Tel.: / (+44-1932) 35.73.61
Fax: / (+44-1932) 35.75.95
e-mail address: /
website: / http://www.vla.gov.uk
Name of Head of Laboratory (Responsible Official): / Dr Robert H. Davies
Name of OIE Reference Expert: / Dr Robert H. Davies
Name of writer of this report
(if different from above): / Dr Doris Mueller-Doblies
Part I: Summary of general activities related to the disease
1. Test(s) in use/or available for the specified disease/topic at your laboratory
Test / For / Specificity / Total (approximate)Serotyping / Antigen / Serotype / 7,362
Phagetyping / Antigen / Phage type / 1,679
Antimicrobial susceptibility testing / Antigen / Phenotype resistogram v. 16 antimicrobials / 4,581
Tests for live Salmonella vaccines / Antigen / Antigen/biochemical/
antimicrobial susceptibility / 734
SAT (S.Pullorum/Gallinarum) / Antibodies / Group / 1,403
TAT (S.Pullorum/Gallinarum) / Antibodies / Group / 38
MAT (S.Arizona) / Antibodies / Type / 0
SAT (S.Abortusequi) / Antibodies / Type / 281
SAT (S.Dublin) / Antibodies / Type / 65
SAT (S.Typhimurium) / Antibodies / Type / 24
ELISA (S.Enteritidis) / Antibodies / Group / 0
ELISA (Porcine Gp B/C1) / Antibodies / Group / 0
Salmonella culture / Bacterial isolation / Genus/group / 21,885
Salmonella culture tests for exported animals / Bacterial isolation / Serotype/Phage type / 55
Real Time PCR CMY-2 gene / Resistance gene / Gene / 10
PCR / gene / S. Typhimurium confirmation / 56
PCR / Genes (thrW island), / Type / 56
PCR (duplex)
/ fljB and intergenic region / 4,5,12;i;- S.Typhimurium and Agama, Lagos, Gloucester, Tsevie, Tumodi / 53Genome sequencing
/ DNA / 4,5,12;i;- & S. Typhimurium / 19VNTR
/ DNA / S. Enteritidis typing / 150VNTR
/ DNA / S. Typhimurium / 2502. Production and distribution of diagnostic reagents
Salmonella Pullorum stained antigen for use in the rapid slide agglutination test is produced and marketed by the Veterinary Laboratories Agency mainly for use within UK Control Programmes such as the Poultry Health Scheme. A range of Salmonella antiserum serotyping products is produced by the VLA and many of these are marketed throughout the world by Pro-Lab Diagnostics (PLD). In total, approximately7,800 x 3 ml vials wereproducedover the year and 5,300 vials sold commercially. Circa 25% of these were marketed to other OIE member countries. Salmonella Pullorum antiserum was also produced in the laboratory and a small amount, approximately 216 x 0.25 ml, has been supplied to the EU, but was mainly used in UK Control Programmes.
Part II: Activities specifically related to the mandate
of OIE Reference Laboratories
3. International harmonisation and standardisation of methods for diagnostic testing or the production and testing of vaccines
The laboratory has been involved in EU ring trials on serotyping, phage typing, antimicrobial resistance testing and isolation. Various international collaborations involving molecular characterisation are on-going. The laboratory also participated in a VNTR trial for method harmonisation with Statens Serum Institut, Denmark.
The laboratory has assisted EC, EFSA and ISO in developing standard methods for Salmonella sampling and testing in surveillance programmes and has also been involved in EFSA working groups on Salmonella Surveillance and Control. Several publications relating to detection of Salmonella have been published or are in press.
4. Preparation and supply of international reference standards for diagnostic tests or vaccines
Not applicable.
5. Research and development of new procedures for diagnosis and control
The development and evaluation of inactivated and live Salmonella vaccines for poultry and pigs in association with several commercial sponsors has continued, with a particular focus on effective delivery of the vaccines and extending the vaccinal cover. A workshop on Salmonella vaccines in pigs was hosted by the VLA on 29th June 2010 and brought together delegates from Defra, the pig industry, medicines licensing authorities, pharmaceutical companies and the research community to discuss essential elements of future research to deliver an effective vaccine.
As part of an internal research project, a number of Salmonella isolates (~200) from the VLA culture collection of Salmonella were tested by MALDI-ToF during 2010 to 2011 to determine if MALDI-ToF was a reliable way to identify Salmonella to the Genus and serotype level, and also if MALDI-ToF was able to distinguish the Gallivac SE vaccine strain from wildtype strains of the same serotype. MALDI-ToF was able to reliably identify Salmonella to the Genus level, but not to the serotype level and was unable to reliably distinguish between the vaccine strain and wildtype strains of the same serotype.
Comparative Evaluation of Molecular-Based Microarray Tools for the detection and serotyping of Salmonella species: Evaluation of a commercial molecular array was performed on a panel of 146 known positive Salmonella isolates from the VLA reference stock collection and 10 non- Salmonella bacterial isolates. This was followed by testing 900 field isolates in parallel with Kauffmann-White serotyping. The evaluation indicated that the system failed to meet the EU regulations for accuracy of Salmonella typing including S. Enteritidis. In addition, the high levels of repeat testing made the array more expensive and a detailed knowledge of Salmonella serotypes was required to interpret some of the data generated. The array was considered unsuitable for full development into an effective rapid alert system. An alternative molecular Salmonella serotyping system is currently in development but there are plans to validate this if it proves suitable for mass screening. In addition, another commercial array-based Luminex system is currently being evaluated.
In 2010, EFSA concluded that, within Salmonella Typhimurium-like strains, monophasic variants lacking the second phase H antigen (1,4,[5],12:i:-), encoded by fljB, appear to be of increasing importance in many EU Member States. Validation is underway of PCRs to confirm untypable S Typhimurium (ST)-like group B Salmonella strains as ST, to identify lack of flagella genes in order to confirm as monophasic (m), and to identify the presence of a genomic island that is characteristic of current epidemic mST strains. A research project to characterise the phylogenetic relationship of monophasic Salmonella enterica subsp. Enterica (subspecies 1) serotype 4,[5[,12:i:- DT193 and other phage type mST strains by complete genome sequencing has commenced. In parallel with this a field study of the distribution of mST in cattle and pig farms, using quantitative microbiology, is in progress.
The laboratory continues to be engaged in research into the epidemiology of Salmonella infection in breeding and finishing herds of pigs. Risk assessment modelling has focused on Salmonella in pork production.The EFSA “Salmonella in pigs quantitative microbiological risk assessment (QMRA)”, led by VLA in collaboration with Food-DTU (Denmark) and RIVM (The Netherlands), was published on the EFSA website in April 2010.There has been continued development of the QMRA and a UK Cost-Benefit Analysis for Salmonella in pigs, specifically to assist the development of the UK National Control Plan for Salmonella in pigs. Additionally, a qualitative risk assessment was carried out to assess the risks of UK consumers being exposed to antimicrobial resistant strains of Salmonella in food products of animal origin.
Research on Salmonella control in commercial laying flocks continued by developing improved auditing procedures for farms, samplers and laboratories, investigating contamination of eggs by S.Typhimurium, investigating the effects of organic acids and various vaccination protocols. A Bayesian model that estimates the true prevalence of Salmonella in laying flocks from age-stratified data from NCP (National Control Programme) sampling (official and operator) has been completed. A simulation model of the NCP in laying flocks has also been completed and used to estimate the proportion of infected flocks that can be detected by the surveillance systems.
6. Collection, analysis and dissemination of epizootiological data relevant to international disease control
Data derived from national Salmonella control programmes was supplied to the European Commission, and annual reports of Salmonella in livestock and a UK Zoonoses Report were produced. The laboratory contributed to EFSA analyses of EU Baseline surveys.
A research project is currently analysing data collected on the UK Breeding Pig Salmonella Survey to obtain information on the risk factors of transmission of the infection in pigs. VNTR testing of S. Typhimurium and S. Enteritidis isolates, as well as incorporating the EFSA breeding pig survey data into the QRA model is in progress. A national meeting to disseminate the results is likely to take place at the end of September 2011.
7. Provision of consultant expertise to OIE or to OIE Members
Numerous ad-hoc queries from a variety of OIE member countries have been answered, and test or advisory control protocols supplied where required. VLA scientists acted as consultants to EC and EFSA.
8. Provision of scientific and technical training to personnel from other OIE Members
Training in field epidemiological investigations, detection, phenotypic and molecular typing, statistical epidemiology and risk modelling is available on a commercial basis.
9. Provision of diagnostic testing facilities to other OIE Members
Salmonella serotyping and phage typing was carried out on isolates from a range of nations.
10. Organisation of international scientific meetings on behalf of OIE or other international bodies
Not applicable
11. Participation in international scientific collaborative studies
The laboratory participated in collaborative studies on various molecular diagnostics and characterisation methods, biological control, and risk modelling during 2010. Collaborations are also in place with key European partners through the new Med-Vet-Net Association.
12. Publication and dissemination of information relevant to the work of OIE (including list of scientific publications, internet publishing activities, presentations at international conferences)
¡ Presentations at international conferences and meetings
Beutlich, J., Jaber, M., Thomas, K., Schroeter, A., Granier, S., Herrera Leon, S., Hopkins, K., Luzzi, I., Nagy, B., Szych, J., Torpdahl, M., Veldman, K., Wu, G., Appel, B., Threlfall, J., Mevius, D., Helmuth, R. and Guerra, B. Salmonella genomic Island 1 variants in Salmonella enterica subsp. enterica serovar Newport isolates collected within the European Project Med-Vet-Net (WP21) (2010). In: Proceedings of I3S International Symposium Salmonella and Salmonellosis, St Malo, France, June 28-30. 179-180.
DANGUY DES DESERTS, J., CARRIQUE-MAS, J., VAUGHAN, K., MCLAREN, I., CANNING, P., WINTRIP, A., MUELLER-DOBLIES, D. and DAVIES, R. (2010) Salmonella infection in turkeys in Great Britain: a longitudinal study in different types of production. In: Proceedings of I3S International Symposium Salmonella and Salmonellosis, St Malo, France, June 28-30. 223-226.
DAVIES, R. (2010) Control of Salmonella in the EU - successes and future challenges. In: Proceedings of I3S International Symposium Salmonella and Salmonellosis, St Malo, France, June 28-30. (Keynote lecture).
DAVIES, R. and CARRIQUE-MAS, J. (2010) Clearance of Salmonella from laying flocks after eradication of rodents from laying houses. In: Proceedings of I3S International Symposium Salmonella and Salmonellosis, St Malo, France, June 28-30. 435-437.
DAVIES, R. and CARRIQUE-MAS, J. (2010) Studies on the use of organic acids and competitive exclusion agents in commercial laying flocks infected with S.Enteritidis. In: Proceedings of I3S International Symposium Salmonella and Salmonellosis, St Malo, France, June 28-30. 441-443.
DAVIES, R. and CARRIQUE-MAS, J. (2010) Investigation of the efficiency of delivery of Salmonella vaccines in laying hens. In: Proceedings of I3S International Symposium Salmonella and Salmonellosis, St Malo, France, June 28-30. 411-415.
DAVIES, R., MUELLER-DOBLIES, D. and CARRIQUE-MAS, J. (2010) Clearance of Salmonella from turkey and broiler farms. In: Proceedings of I3S International Symposium Salmonella and Salmonellosis, St Malo, France, June 28-30. 445-449.
FEATHERSTONE, C., REICHEL, R., SNOW, L., DAVIES, R., CHRISTIANSEN, K., CARRIQUE-MAS, J. and EVANS, S. (2010) Investigation of risk factors for Salmonella on fattening-turkey farms. In: Proceedings of I3S International Symposium Salmonella and Salmonellosis, St Malo, France, June 28-30. 297-298.
Hill, A.A., Swart, A., Simons, R.R.L., Kelly, L., Hald, T., Evers, E., Snary, E.L. (2010). An analysis of potential on-farm and abattoir interventions to reduce human salmonellosis in EU member states attributable to pig meat consumption. Society for Risk Analysis Annual Meeting, Salt Lake City, USA, 6-8 December 2010.
MCLAREN, I., WALES, A., BRESLIN, M., CARRIQUE-MAS, J. and DAVIES, R. (2010) In vitro models for the realistic evaluation of the efficacy of different disinfectants against Salmonella in poultry houses. In: Proceedings of I3S International Symposium Salmonella and Salmonellosis, St Malo, France, June 28-30. 487-490.
MUELLER-DOBLIES, D., CARRIQUE-MAS, J., SAYERS, A.R. and DAVIES, R. (2010) A comparison of the efficacy of different disinfection methods in eliminating Salmonella contamination from turkey houses. In: Proceedings of I3S International Symposium Salmonella and Salmonellosis, St Malo, France, June 28-30. 451-454.
Papadopoulou, C., Simons, R.R.L., Vidal-Diez, A., Twomey, D.F., Millar, M. (2010). Early detection of Salmonella Dublin outbreak in cattle in Great Britain using spatio-temporal epidemiological methods. SVEPM 2010 Proceedings, Nantes, France, pg 19-27.
RABIE, A., CARRIQUE-MAS, J. and DAVIES, R. (2010) Persistence of Salmonella in rodent populations from infected farms in Great Britain. In: Proceedings of I3S International Symposium Salmonella and Salmonellosis, St Malo, France, June 28-30. 219-222.
SNARY, E.L. (2010). The EFSA quantitative microbiological risk assessment for Salmonella in slaughter pigs. In: Proceedings of I3S International Symposium Salmonella and Salmonellosis, St Malo, France, June 28-30. 425-428.
Snary, E.L., Simons, R.R.L., Swart, A.N., Vigre, H., Domingues, A.R., Hald, T., Evers, E., Tennant, J., Kelly, L., Hill, A.A. (2010) A quantitative microbiological risk assessment for Salmonella in pigs for Individual EU member states. Society for Risk Analysis Annual Meeting, Salt Lake City, USA, 6-8 December 2010.
Swart, A.N., Evers, E., Simons, R.R.L., Hill, A.A., Hald, T (2010). Modelling of Salmonella dynamics in the pig slaughterhouse. Society for Risk Analysis Annual Meeting, Salt Lake City, USA, 6-8 December 2010.
TEALE, C., COLDHAM, N., KIRCHNER, M., RANDALL, L., WEARING, H., CHAPPELL, S., LYNCH, K., WISE, G., SPEED, K., BENNETT, G., PAPADOPOULOU, C. (2010). Recent trends in antimicrobial resistance in Salmonella spp. from animals, their environment and animal feed in Great Britain. In: Proceedings of I3S International Symposium Salmonella and Salmonellosis, St Malo, France, June 28-30. 151-154.