Evaluation of safety assurance measures for Salmonella in pork production in Switzerland

The safety of foods of animal origins is provided in Switzerland through various sampling strategies and production processes throughout the production chain. Dispersion and heterogeneity of the information on the implementation of these safety assurance measures hinder a general overview and make an evaluation of the level of the safety provided difficult. A full inventory of the elements implicated in the pork production system was conducted. Information on sampling strategies and production processes was collected. The level of safety assurance provided regarding Salmonella was evaluated at every step of the pork production chain by integrating this information using a semi-quantitative method. The results showed that in the pork production chain, the level of safety assurance varied between production steps. Weaknesses were detected, especially in compound feed production and animal production. Results of this analysis will be used to improve the existing implemented safety assurance measures

Risk factors for antibiotic resistance in Campylobacter spp. isolated from raw poultry meat in Switzerland

BACKGROUND: The world-wide increase of foodborne infections with antibiotic resistant pathogens is of growing concern and is designated by the World Health Organization as an emerging public health problem. Thermophilic Campylobacter have been recognised as a major cause of foodborne bacterial gastrointestinal human infections in Switzerland and in many other countries throughout the world. Poultry meat is the most common source for foodborne cases caused by Campylobacter. Because all classes of antibiotics recommended for treatment of human campylobacteriosis are also used in veterinary medicine, in view of food safety, the resistance status of Campylobacter isolated from poultry meat is of special interest. METHODS: Raw poultry meat samples were collected throughout Switzerland and Liechtenstein at retail level and examined for Campylobacter spp. One strain from each Campylobacter-positive sample was selected for susceptibility testing with the disc diffusion and the E-test method. Risk factors associated with resistance to the tested antibiotics were analysed by multiple logistic regression. RESULTS: In total, 91 Campylobacter spp. strains were isolated from 415 raw poultry meat samples. Fifty-one strains (59%) were sensitive to all tested antibiotics. Nineteen strains (22%) were resistant to a single, nine strains to two antibiotics, and eight strains showed at least three antibiotic resistances. Resistance was observed most frequently to ciprofloxacin (28.7%), tetracycline (12.6%), sulphonamide (11.8%), and ampicillin (10.3%). One multiple resistant strain exhibited resistance to five antibiotics including ciprofloxacin, tetracycline, and erythromycin. These are the most important antibiotics for treatment of human campylobacteriosis. A significant risk factor associated with multiple resistance in Campylobacter was foreign meat production compared to Swiss meat production (odds ratio = 5.7). CONCLUSION: Compared to the situation in other countries, the data of this study show a favourable resistance situation for Campylobacter strains isolated from raw poultry meat produced in Switzerland. Nevertheless, the prevalence of 19% ciprofloxacin resistant strains is of concern and has to be monitored. "Foreign production vs. Swiss production" was a significant risk factor for multiple resistance in the logistic regression model. Therefore, an adequate resistance-monitoring programme should include meat produced in Switzerland as well as imported meat samples

Evaluation of safety assurance measures for Salmonella in pork production in Switzerland

The safety of foods of animal origins is provided in Switzerland through various sampling strategies and production processes throughout the production chain. Dispersion and heterogeneity of the information on the implementation of these safety assurance measures hinder a general overview and make an evaluation of the level of the safety provided difficult. A full inventory of the elements implicated in the pork production system was conducted. Information on sampling strategies and production processes was collected. The level of safety assurance provided regarding Salmonella was evaluated at every step of the pork production chain by integrating this information using a semi-quantitative method. The results showed that in the pork production chain, the level of safety assurance varied between production steps. Weaknesses were detected, especially in compound feed production and animal production. Results of this analysis will be used to improve the existing implemented safety assurance measures.</p

Antimicrobial resistance monitoring in Swiss pork production

An optimized national resistance monitoring program should deliver a precise estimate of the resistance situation for a given combination of bacteria and antimicrobial at a low cost. In order to achieve this, decisions need to be made on the number of samples to be collected at each of different possible sampling points along the food production line.</p

Prevalence of Salmonella in fattening pigs and pork from animal friendly farms

The objective of this project is to compare the prevalence of Salmonella spp, Campylobacter coli/jejuni and Yersinia spp in pigs and in pork from traditional housing systems to new animal friendly systems. On a representative sample of 50 traditional and 50 animal-friendly farms, faecal samples are collected. Faecal culture is performed for all three micro-organisms; isolated strains are further characterised. From a batch of pigs of each farm, meat samples are collected at the slaughterhouse and presence of anti-Salmonella spp antibodies is tested by meat juice analysis. Additionally, fresh pork cuts from animal friendly and conventional production are collected from 300 retailers. Analysis results from farm, slaughterhouse and retail level are compared. The influence of the production systems is assessed using regression analysis, correcting for other possible risk factors. The outcome of this study will be used as a basis for the development of new control strategies for zoonotic pathogens on Swiss fattening farms.</p

Serosurveillance of Schmallenberg virus in Switzerland using bulk tank milk samples.

Infections with Schmallenberg virus (SBV), a novel Orthobunyavirus transmitted by biting midges, can cause abortions and malformations of newborns and severe symptoms in adults of domestic and wild ruminants. Understanding the temporal and spatial distribution of the virus in a certain territory is important for the control and prevention of the disease. In this study, seroprevalence of antibodies against SBV and the spatial spread of the virus was investigated in Swiss dairy cattle applying a milk serology technique on bulk milk samples. The seroprevalence in cattle herds was significantly higher in December 2012 (99.5%) compared to July 2012 (19.7%). This high between-herd seroprevalence in cattle herds was observed shortly after the first detection of viral infections. Milk samples originating from farms with seropositive animals taken in December 2012 (n=209; mean 160%) revealed significantly higher S/P% ratios than samples collected in July 2012 (n=48; mean 103.6%). This finding suggests a high within-herd seroprevalence in infected herds which makes testing of bulk tank milk samples for the identification farms with past exposures to SBV a sensitive method. It suggests also that within-herd transmission followed by seroconversion still occurred between July and December. In July 2012, positive bulk tank milk samples were mainly restricted to the western part of Switzerland whereas in December 2012, all samples except one were positive. A spatial analysis revealed a separation of regions with and without positive farms in July 2012 and no spatial clustering within the regions with positive farms. In contrast to the spatial dispersion of bluetongue virus, a virus that is also transmitted by Culicoides midges, in 2008 in Switzerland, the spread of SBV occurred from the western to the eastern part of the country. The dispersed incursion of SBV took place in the western part of Switzerland and the virus spread rapidly to the remaining territory. This spatial pattern is consistent with the hypothesis that transmission by Culicoides midges was the main way of spreading

Symposium report: One Health meets sequencing

Whole genome sequencing (WGS) has become the new gold standard for typing and characterization of pathogens. WGS enables understanding transmission chains of bacteria, exchange of mobile genetic elements, and variation in viruses with the highest resolution. In the near future, national and international databases will allow the tracking of pathogen transmissions based on WGS data in and across complex settings such as humans, animals, food, water and other environmental sources. Understanding the complexity and dynamics of and across these compartments will also help us to reduce transmissions of multi-drug resistant pathogens. Several important challenges for Public Health and One Health-related questions need to be identified such as defining standards for data analysis, accessing important epidemiological metadata, sharing data sharing while respecting data protection and ethical considerations. This symposium brought together leading institutions and fostered the ongoing discussion on the identified challenges, paving the way for solutions in public health, diagnostics, and research. This symposium report summarizes the key messages