Cefotaxime-resistant E. coli in dairy and beef cattle farms-Joint analyses of two cross-sectional investigations in Germany.

Resistance to third-generation cephalosporins and other beta-lactam antibiotics is of major concern for animal and human health. Knowledge of the prevalence of resistant bacteria in primary production is an important element to estimate transmission along the stages in the food production chain and the exposure of the human population. The primary objective of this study was to determine the prevalence of cefotaxime-resistant commensal E. coli in dairy and beef cattle production units throughout Germany. Secondarily, the association between management factors and the presence of cefotaxime resistance was investigated. In total, 60 beef cattle and 52 dairy cattle production units all over Germany were included. Cefotaxime-resistant E. coli were isolated from at least one sample in 70% (95% CI: 58-83%) of the farms keeping beef cattle and 85% (95% CI: 75-94%) of the farms keeping dairy cattle. The sample prevalence was 35% (161/455; 95% CI: 31-40%) and 48% (156/323; 95% CI: 43-54%), respectively. Most factors associated with resistance to cefotaxime indicate that less intensive production results in a lower number of positive samples. For beef cattle, antimicrobial treatment of the whole animal group was significantly associated with an increased proportion of samples containing cefotaxime resistant E. coli. In addition, our results indicate that better hygiene management could improve the resistance situation on cattle farms.

Antibiotic Resistances in Livestock: A Comparative Approach to Identify an Appropriate Regression Model for Count Data.

Antimicrobial resistance in livestock is a matter of general concern. To develop hygiene measures and methods for resistance prevention and control, epidemiological studies on a population level are needed to detect factors associated with antimicrobial resistance in livestock holdings. In general, regression models are used to describe these relationships between environmental factors and resistance outcome. Besides the study design, the correlation structures of the different outcomes of antibiotic resistance and structural zero measurements on the resistance outcome as well as on the exposure side are challenges for the epidemiological model building process. The use of appropriate regression models that acknowledge these complexities is essential to assure valid epidemiological interpretations. The aims of this paper are (i) to explain the model building process comparing several competing models for count data (negative binomial model, quasi-Poisson model, zero-inflated model, and hurdle model) and (ii) to compare these models using data from a cross-sectional study on antibiotic resistance in animal husbandry. These goals are essential to evaluate which model is most suitable to identify potential prevention measures. The dataset used as an example in our analyses was generated initially to study the prevalence and associated factors for the appearance of cefotaxime-resistant Escherichia coli in 48 German fattening pig farms. For each farm, the outcome was the count of samples with resistant bacteria. There was almost no overdispersion and only moderate evidence of excess zeros in the data. Our analyses show that it is essential to evaluate regression models in studies analyzing the relationship between environmental factors and antibiotic resistances in livestock. After model comparison based on evaluation of model predictions, Akaike information criterion, and Pearson residuals, here the hurdle model was judged to be the most appropriate model.

Simultaneous occurrence of Salmonella enterica, Campylobacter spp. and Yersinia enterocolitica along the pork production chain from farm to meat processing in five conventional fattening pig herds in Lower Saxony.

The objectives of this study were to gather data on the occurrence of Salmonella (S.) enterica, Campylobacter spp. and Yersinia (Y.) enterocolitica along the pork production chain and to further analyze detected Salmonella isolates by additionally applying MLVA (multiple-locus variable-number tandem repeat analysis). In total, 336 samples were collected at primary production, slaughter and meat processing from five conventional fattening pig farms and one common slaughterhouse. At farm level, S. enterica, Campylobacter spp. and Y. enterocolitica were detected in 19.4%, 38.9% and 11.1% of pooled fecal samples of fattening pigs. At slaughter, more than two-thirds of examined carcasses, 24% of carcass surfaces samples and about 60% of cecal content samples were positive for at least one of the examined pathogens. An amount of 4% of meat samples were positive for non-human pathogenic Y. enterocolitica. Identical MLVA patterns of Salmonella isolates from farm- and associated slaughterhouse samples demonstrated transmission across both production stages. Other MLVA patterns found at slaughter indicated possible colonization of pigs during transport or lairage and/or cross-contamination during slaughter. Identical MLVA patterns from risk tissues and the nearby carcass surface evidenced a direct contamination of carcasses as well. Overall, our data showed wide distribution ranges for all three examined pathogens within the pig production chain and underline the need for appropriate intervention strategies at pre- and postharvest.

Cefotaxime-resistant Escherichia coli in broiler farms-A cross-sectional investigation in Germany.

In this investigation the farm prevalence of cefotaxime-resistant Escherichia coli (CREC) in German broiler farms was evaluated. In total, 59 flocks on 34 broiler farms were sampled in four agricultural regions of Germany. Per broiler flock, three faecal samples, a pair of boot swabs and one dust sample were taken and examined for the presence of CREC. After pre-enrichment of sample material in Luria-Bertani-broth, the broth was streaked onto MacConkey agar containing 1mg/l cefotaxime (CTX). CREC isolates were detected in at least one sample from each flock resulting in a farm prevalence of 100%. The proportion of positive samples was high in all three sample types. Of 177 collective faecal samples 81.9% were positive, of 59 boot swabs and 59 dust samples 79.7% and 62.7% were positive. In conclusion, the prevalence of broiler farms with cefotaxime-resistant E. coli in Germany is very high. We suggest that the analysis of collective faecal samples is sufficient to determine the CREC farm status. In addition to other studies our study supports the finding that cefotaxime resistance is a good proxy for the presence of ESBL- or plasmidic AmpC-beta-lactamases.

Cross-sectional study on antibiotic usage in pigs in Germany.

To be able to analyze the relationship between the level of resistance and the use of antimicrobials, it is necessary to collect detailed data on antimicrobial usage. For this reason, data on antimicrobial use on 495 pig farms from entire Germany were collected and analyzed. In Germany, each application and dispensing of medicines to food-producing animals is documented in detail obligatorily by the veterinarian. This information was collected retrospectively for the year 2011. The analyses undertook separate examinations on the age groups sow, piglet, weaner and fattening pig; both the route of administration and indication per active ingredient, and active ingredient class, were evaluated. In total, 20,374 kg of antimicrobial substances were used in the study population. Tetracyclines were used in highest amounts, followed by beta-lactams, trimethoprim-sulfonamides and macrolides. Concerning the frequency of using an active substance per animal, polypeptides were most commonly administered. In all age groups, respiratory infections were the main indication for using antimicrobials, followed by intestinal diseases in piglets, weaners and fattening pigs and diseases of reproductive organs in sows. Over a period of 100 days, the median number of treatment days with one antimicrobial substance for piglets was 15 days, for weaners about 6 days, for fattening pigs about 4 days and for sows about 1 day. A multifactorial ANOVA was conducted to investigate which factors are associated with the treatment frequency. The factors "veterinarian" and "age group" were related to the treatment frequency, just as the interaction between "veterinarian" and "farm size" as well as the interaction between "veterinarian" and "age group".

Prevalence and potential risk factors for the occurrence of cefotaxime resistant Escherichia coli in German fattening pig farms--a cross-sectional study.

A cross-sectional study concerning farm prevalence and risk factors for the count of cefotaxime resistant Escherichia coli (E. coli) (CREC) positive samples per sampling group on German fattening pig farms was performed in 2011 and 2012. Altogether 48 farms in four agricultural regions in the whole of Germany were investigated. Faecal samples, boot swabs and dust samples from two sampling groups per farm were taken and supplemental data were collected using a questionnaire. On 85% of the farms, at least one sample contained cefotaxime resistant E. coli colonies. Positive samples were more frequent in faeces (61%) and boot swabs (54%) than in dust samples (11%). Relevant variables from the questionnaire were analysed in a univariable mixed effect Poisson regression model. Variables that were related to the number (risk) of positive samples per sampling group with a p-value <0.2 were entered in a multivariable model. This model was reduced to statistically significant variables via backward selection. Factors that increased the risk for positive samples involved farm management and hygienic aspects. Farms that had a separate pen for diseased pigs had a 2.8 higher mean count of positive samples (95%-CI [1.71; 4.58], p=0.001) than farms without an extra pen. The mean count was increased on farms with under-floor exhaust ventilation compared to farms with over floor ventilation (2.22 [1.43; 3.46], p=0.001) and more positive samples were observed on farms that controlled flies with toxin compared to farms that did not (1.86 [1.24; 2.78], p=0.003). It can be concluded, that CREC are wide spread on German fattening pig farms. In addition the explorative approach of the present study suggests an influence of management strategies on the occurrence of cefotaxime resistant E. coli.

[Antibiotic usage and antibiotic sales in Germany in 2011--the situation of drug usage in veterinary medicine]. / Antibiotikaverbrauch und Antibiotikaverkauf in Deutschland im Jahr 2011--Zur Situation des Arzneimitteleinsatzes in der Veterinärmedizin.

To appreciate the significance of sales data of antibiotics, data on antibiotic consumption (which were collected for selected food-producing animals within the representative VetCAb pilot study in Germany in 2011) were extrapolated for the total German animal population, and subsequently compared to the antibiotic sales data, which were collected throughout Germany in 2011 for the first time and which were published by the Federal Office of Consumer Protection and Food Safety (BVL). The extrapolation was realized based on the average dosage and the number of treatment units determined in the VetCAb pilot project for each active ingredient and animal species. It was extrapolated that 1302 tons of antimicrobial substances were consumed for treating cattle, pigs and broilers--this amount is accompanied by the amount of 1706 tons sold for all animal species. In Germany, tetracyclines and beta-lactams are the most commonly used and sold antimicrobial drugs. In third place are the potentiated sulfonamide, in fourth and fifth place, macrolides and polypeptides. To describe and evaluate the antibiotic usage for the several food-producing animals, detailed information is needed. Therefore, the number of treatments per active ingredient per animal and per day (treatment unit), and the number of treatment days per active ingredient per animal (treatment frequency) were calculated in the VetCAb project. These values represent scientifically collected orientation values for the treatment frequency of food-producing animal with antimicrobial substances in Germany. For example, a fattening pig is treated at 4.2 days (median) with one active ingredient within its 115-day fattening period. A dairy cow is treated at 3.5 days with one active ingredient within one year. A broiler is treated at 10 days with one active ingredient within its 39-day production period.

[On the occurence of extended-spectrum- and AmpC-beta-lactamase-producing Escherichia coli in livestock: results of selected European studies]. / Zum Vorkommen von Extended-Spektrum- und AmpC-Beta-Laktamase-produzierenden Escherichia coli in Nutztierbeständen: Ergebnisse ausgewählter europäischer Studien.

Extended-spectrum-beta-lactamase (ESBL) and plasmid-encoded cephamycinase (pAmpC) producing Escherichia (E.) coli in livestock farms have recently been matter of growing scientific and public concern. This article summarises selected European studies which focus on the prevalence and risk factors associated with the presence of such resistant E. coli isolates in livestock farms. Due to the different methodologies used in these studies, they cannot be compared directly; nonetheless, the overall prevalence found is very high. The prevalence found in broiler farms was higher than 40% and the individual animal prevalence was ca. 30%. The prevalence was more variable in pigs, with reports of pig farms showing prevalence of 1 to 80% and reports of individual animal prevalence of 15 to 100% In studies on cattle farms the production type as well as the age of animals had an influence on the number of positive samples. The highest prevalence was found with calves after birth and in the first weeks, whereas with older cattle the numbers of positive samples were considerably lower. Samples taken from dairy cows were positive more often after calving than before calving. According to the livestock species different risk factors may be assessed for the occurrence of ESBL/pAmpC-producing E. coli isolates. In some studies an association between the occurrence of ESBL-producing E. coli and factors like the use of antimicrobial agents or management factors, as the duration of the fattening period and the acquisition of animals from different origins, were identified. At the moment, there is a lack of systematic and standardised transnational epidemiological investigations on the occurrence of ESBL/pAmpC-producing E. coli in livestock. To control the further spread of ESBL/pAmpC-producing E. coli and the effectiveness of preventive measures, comprehensive monitoring and surveillance systems with harmonised methods are essential. Modern typing methods, in particular the sequence-based methods, can provide more information to clarify transmission pathways.

[Variables describing the use of antibiotics in food-producing animals]. / Variablen zur Beschreibung des Antibiotikaeinsatzes beim Lebensmittel liefernden Tier.

In order to represent relationships between the use of antibiotics in food-producing animals and the extend of bacteria with resistance characteristics, it is necessary to have access to information about dispensary and consumption of antibiotic drugs. This does not only require suitable detection methods, but also the establishment of figures which adequately describe the use of antibiotics both on the level of the enterprise, respectively veterinarian, as well as in cumulative form. In various countries different calculations for the analysis of data on antibiotic use are applied, therefore the results are not always comparable.The aim of this publication is to provide an overview of the national and international terminology and variables, to give concrete definitions and to identify those variables most suitable for particular objectives. Hereby a contribution to the standardization of evaluations should be made, to enable a comparison of data on use of antibiotics from various sources of information.