Antimicrobial Use Surveillance Indicators for Finfish Aquaculture Production: A Review.

Quantification and tracking of antimicrobial use (AMU) are key factors for the development of responsible antimicrobial stewardship programs and comparison between countries. Global finfish aquaculture growth and increased AMU creates the potential for exchange of antimicrobial resistance between aquatic and terrestrial environments, making AMU surveillance imperative for this industry. The objective of this review is to collate current literature on AMU surveillance indicators and their application to commercial finfish aquaculture production. A systematic search strategy was applied to five databases: Medline, Embase, Agricola, CAB abstracts, and Biosis. To be included, studies must report on at least one AMU surveillance indicator for use in animals. There is no single, standardized indicator suitable to report finfish aquaculture AMU. The type and availability of finfish aquaculture data presents unique considerations for AMU reporting. Ultimately, the indicator used should be fit-for-purpose to satisfy the objective of the surveillance program, motivation for comparison and provide useful information to the industry stakeholders. Finfish aquaculture total annual slaughter weight allows estimation of biomass for the population correction unit (PCU) to report annual total mg of active antimicrobial ingredient per PCU. These data are commonly reported by finfish aquaculture-producing countries, allowing for international comparisons. However, this precludes the ability to compare to terrestrial livestock where the PCU is based on animal numbers and an average treatment weight, which are not available for finfish aquaculture. The mg per adjusted PCU indicator provides an interesting alternative that incorporates the length of the marine grow-out phase for finfish, but is subject to the same limitations. The number of defined daily doses animal per animal-days-at-risk is useful but also limited by a lack of a defined average treatment weight. The concept of average treatment weight remains challenging for the industry as it does not accurately reflect the timing of actual AMU to fish in the system. The term "average biomass" is more reflective of the intent of AMU surveillance indicators. Defining an average treatment weight, or average biomass, will require industry engagement, which is crucial if AMU reporting is to be deemed credible and provide value back to the finfish aquaculture industry.

Developing an evidence-based approach for antimicrobial resistance reporting for British Columbia diagnostic animal health laboratory data.

Antimicrobial resistance (AMR) data generated by diagnostic animal health laboratories are underutilized for AMR reporting in Canada. Data assessment, review of practices in other jurisdictions, and expert interviews were used to develop an evidence-guided plan to generate AMR reports from British Columbia Animal Health Centre (AHC) data that would provide transparent, timely, and useful information to public health practitioners, the food animal sector, and the general public. Using the Canadian Animal Health Surveillance Network (CAHSN) platform was the most efficient method of data retrieval. Project outputs included 2 publicly available reports. The public health report included AMR information for methicillin-resistant Staphylococcus aureus, Escherichia coli, and Salmonella. The animal health report included AMR information for Aeromonas salmonicida and Yersinia ruckeri from Atlantic salmon, bacteria from bovine milk samples, and staphylococci from broiler chickens. A preliminary comparison was conducted between selected AHC data and publicly available Canadian Integrated Program for Antimicrobial Resistance Surveillance (CIPARS) reports.

Développement d'une approche factuelle pour la déclaration de la résistance aux antimicrobiens pour les données des laboratoires diagnostiques de santé animale en Colombie-Britannique. Les données sur la résistance aux antimicrobiens produites par les laboratoires diagnostiques de santé animale sont sous-utilisées pour la déclaration de la résistance aux antimicrobiens au Canada. L'évaluation des données, l'examen des pratiques dans les autres territoires et des entrevues avec des experts ont été utilisés afin de développer un plan fondé sur des données probantes pour produire des rapports sur la résistance aux antimicrobiens à partir des données du British Columbia Animal Health Centre (AHC) qui fourniraient des renseignements transparents, opportuns et utiles aux praticiens de la santé publique, au secteur des animaux destinés à l'alimentation et au grand public. L'utilisation de la plate-forme du Système canadien de surveillance de la santé animale (SCSSA) était la méthode d'extraction des données la plus efficace. Les résultats du projet incluaient deux rapports rendus publics. Le rapport sur la santé publique incluait les renseignements sur la résistance aux antimicrobiens pour Staphylococcus aureus résistant à la méthicilline, Escherichia coli et Salmonella. Le rapport sur la santé animale comprenait des renseignements sur la résistance aux antimicrobiens pour Aeromonas salmonicida et Yersinia ruckeri du saumon atlantique, les bactéries provenant d'échantillons de lait bovin et les staphylocoques des poulets à griller. Une comparaison préliminaire a été réalisée entre les données de l'AHC et les rapports publics du Programme intégré canadien de surveillance de la résistance aux antimicrobiens (PICRA).(Traduit par Isabelle Vallières).

The distribution of animal antimicrobials in British Columbia for over-the-counter and veterinary sales, 2012 to 2014.

Canadian Animal Health Institute (CAHI) data are used for provincial, national, and international comparisons of Canadian animal antimicrobial use. The objectives of this paper were to: i) use CAHI and British Columbia (BC) antimicrobial distribution data to group BC antimicrobial sales into the following BC retail distribution channels: over-the-counter retail outlets, livestock and poultry feed mills, aquaculture feed mills, livestock and poultry veterinarians, and companion animal veterinarians; and ii) to validate the CAHI BC distribution data and BC's antimicrobial distribution data from 2012 to 2014. Annual total antimicrobial distribution and distribution by antimicrobial class were presented for each distribution channel. The distribution of medically important antimicrobials for production animals was validated, the distribution of ionophores was not. A lack of data precluded any attempt to validate the distribution of antimicrobials for companion animals. Each distribution channel typically experienced substantial fluctuations in total antimicrobial use and use by antibiotic class at least once over the 3-year period. The validated data are useful for evidence-based analysis of a proposed Canadian policy requiring a veterinary prescription for all medically important antimicrobials.

Distribution des antimicrobiens pour animaux en Colombie-Britannique pour la vente de médicaments en vente libre et par des vétérinaires, de 2012 à 2014. Les données de l'Institut canadien de la santé animale (ICSA) sont utilisées pour effectuer des comparaisons provinciales, nationales et internationales de l'utilisation des antimicrobiens chez les animaux au Canada. Cet article avait pour objectifs : i) d'utiliser les données de distribution des antimicrobiens de l'ICSA et de la Colombie-Britannique afin de regrouper les ventes d'antimicrobiens en Colombie-Britannique (C.-B.) selon les réseaux de distribution au détail suivants en C.-B. : les commerces de vente libre, les usines d'aliments pour le bétail et la volaille, les usines d'aliments pour l'aquaculture, les vétérinaires pour le bétail et la volaille et les vétérinaires pour animaux de compagnie; et ii) de valider les données de distribution de l'ICSA en C.-B. ainsi que les données de distribution des antimicrobiens de la C.-B. de 2012 à 2014. La distribution totale annuelle des antimicrobiens et la distribution selon la catégorie d'antimicrobiens ont été présentées selon chaque réseau de distribution. La distribution des antimicrobiens importants sur le plan médical pour les animaux de production a été validée, contrairement à la distribution des ionophores. Une absence de données a empêché toute tentative de valider la distribution des antimicrobiens pour les animaux de compagnie. Chaque réseau de distribution a typiquement présenté des fluctuations substantielles dans l'utilisation totale des antimicrobiens et l'utilisation selon la catégorie d'antibiotique au moins une fois au cours de la période de 3 ans. Les données validées sont utiles pour l'analyse factuelle d'une politique canadienne proposée exigeant une prescription vétérinaire pour tous les antimicrobiens importants sur le plan médical.(Traduit par Isabelle Vallières).

Towards an improved estimate of antimicrobial use in animals: Adjusting the "population correction unit" calculation.

International comparisons of animal antimicrobial use (AMU) have typically been based on total national estimates of antimicrobials sales standardized by the national animal biomass calculated as the population correction unit (PCU). The objective of this paper was to compare the currently accepted PCU calculation with that of the adjusted population correction unit (APCU), which re-evaluates the standard animal weights used in the calculation and accounts for animal lifespan. The APCU calculation resulted in substantial changes to the 2009 national biomass estimates for cattle, pigs, and poultry in 8 European countries and Canada. The estimated national biomass for cattle increased 35% to 43%, while the estimated national biomass of pigs and poultry typically decreased by approximately 51% and 87%, respectively. Among the 9 countries, the total national APCU ranged from an increase of 1% to a decrease of 40% relative to PCU, and these differences were statistically significant. Adjusted population correction unit is preferred over PCU in comparing and contrasting AMU among animals with different lifespans because it is more transparently derived and is a reasonable approximation of the animal biomass at risk of antimicrobial treatment.

Les comparaisons internationales de l'utilisation d'antimicrobiens chez les animaux (UMA) ont typiquement été basées sur les totaux nationaux estimés de ventes d'antimicrobiens standardisés pour la biomasse animale nationale calculée comme l'unité de correction pour la population (UCP). Les objectifs de cet article étaient de comparer les calculs d'UCP présentement acceptés à ceux de l'unité de correction pour la population ajustée (UCPA), qui réévalue les poids animaux standards utilisés dans les calculs et tient compte de la durée de vie des animaux. Les calculs de l'UCPA ont entrainé des changements substantiels aux estimés nationaux de 2009 de la biomasse pour les bovins, porcs et volailles dans 8 pays européens et le Canada. La biomasse nationale estimée pour les bovins a diminué de 35 % à 43 %, alors que les biomasses nationales estimées pour les porcs et les volailles ont typiquement diminué d'environ 51 % et 87 %, respectivement. Parmi les neuf pays, l'UCPA nationale totale variait d'une augmentation de 1 % à une diminution de 40 % relativement à l'UCP, et ces différences étaient statistiquement significatives. L'UCPA est préférée par rapport à l'UCP pour la comparaison et la mise en contraste de l'UMA chez les animaux avec différentes durées de vie étant donné qu'elle est dérivée de manière plus transparente et qu'elle est une approximation raisonnable de la biomasse animale à risque d'un traitement antimicrobien.(Traduit par Docteur Serge Messier).

Evaluation of early conception factor lateral flow test to determine nonpregnancy in dairy cattle.

The early conception factor (ECF) lateral flow test was evaluated for its ability to accurately determine nonpregnant status in dairy cattle. Results of 2 field trials involving 191 cows and 832 tests indicated the probability that a cow can be correctly diagnosed as nonpregnant by using the ECF test is only about 50%. Agreement of test results between milk and serum obtained from the same cow was 57.5%. The ECF test was not consistent in identifying nonpregnancy when the same cows were tested repeatedly over a period of 4 weeks. We conclude that the ECF lateral flow test does not accurately identify nonpregnancy in dairy cattle.

The value of genetic information in selecting dairy replacements.

The objective of this study was to empirically determine the economic value of genetic information in the selection of dairy replacements, and assess whether this value was sufficient to prompt producers to select replacements on this basis. The data set consisted of 1982 Michigan Holstein replacements in 115 herds. Each herd had a minimum of 10 replacements that were born in the last 6 months of 1992 and calved within the last 6 months of 1994. The data for each replacement included the estimated breeding value (EBV) for milk at the beginning and end of the rearing period, and the estimated lifetime profit corrected for the opportunity cost of postponed replacement (ELPCOC). The replacement selection decision for a profit-maximizing dairy producer selecting 70 or 80% of the replacements was modeled. We modeled three methods of selection: genetic, random and ex poste. Genetic selection was evaluated using the EBV milk available at the beginning or end of the rearing period. For each herd, the profit associated with each of the three methods of selection was simulated. The value of the genetic information and perfect information were the differences in herd profits of genetic selection and ex poste selection relative to random selection, respectively. The difference in value of the genetic information between the end of the rearing period and the beginning of the rearing period was the increase in value of the genetic information due to updating. The value of information was calculated as the average herd profit per replacement. The value of the genetic information ranged from 22 dollars/replacement to 30 dollars/replacement and was statistically greater than zero at a 95% confidence level. It is unclear whether this value is sufficient to prompt producers to select replacements on the basis of EBV milk as has been recommended. The negative value of EBV milk (from the end of the rearing period when selecting 80% of the replacements) for 32 herds was consistent with the noisiness of the genetic estimates as messages of ELPCOC. The increased value of the genetic information due to updating was approximately 5 dollars/replacement. This increased value is likely insufficient to warrant delaying replacement selection decisions solely to obtain the updated information. The value of EBV milk was approximately 4 dollars/replacement higher when selecting 70% of the replacements versus 80%. The genetic information captured between 15% (selecting 70% at the beginning of the rearing period) and 20% (selecting 80% at the end of the rearing period) of the value of perfect information.

A demonstration of interval-censored survival analysis.

Interval-censoring occurs in survival analysis when the time until an event of interest is not known precisely (and instead, only is known to fall into a particular interval). Such censoring commonly is produced when periodic assessments (usually clinical or laboratory examinations) are used to assess if the event has occurred. My objectives were to raise awareness about interval-censoring including its existence, the potential ramifications of ignoring its existence, the different types of interval-censored data, and the analytical methods to analyze such data (including availability in standard statistical software). Asynchronous interval-censored survival analysis was demonstrated by parametric evaluation of risk factors for the time to first detected shedding of Salmonella muenster (identified by repeated periodic fecal cultures) for a herd of dairy cows. These results were compared with those from survival analyses which ignored or approximated the interval-censoring. Ignoring or approximating the asynchronous interval-censoring in the survival analysis generally resulted in the risk factors' regression coefficients having the same signs and a decrease (often >50%) in their absolute size. All the standard errors from the three methods of approximating the interval-censoring were <40% of their interval-censored counterparts. The conclusions drawn from the asynchronous interval-censored analysis versus those from the approximations varied dramatically. (The general conclusion from the approximations was that none of the risk factors for this example warranted further consideration.) That ignoring or approximating the left- and interval-censored nature of the dependent variable resulted in biased results was consistent with the literature. In the currently available asynchronous interval-censored models, the inclusion of time-dependent covariates that vary continuously is awkward. Statistical models for the semi-parametric estimation of asynchronous interval-censored survival analysis are not generally available in standard statistical software.

Salmonella Muenster infection in a dairy herd.

The overall purpose of this study was to provide information on animal and occupational health associated with the infection of a diary herd with Salmonella Muenster that would be useful in the management of dairy herds so infected. This retrospective, longitudinal report records a 2-year infection of a 140-cow dairy herd with S. Muenster, which was likely introduced by additions to the herd. Six cows aborted or had diarrhea due to salmonellosis in the last trimester of pregnancy. Additions to the herd and the presence of animals that had not received an Escherichia coli bacterin-toxoid were risk factors for salmonellosis. One neonate died, and 24 of 36 calves born between November 1998 and May 1999 had diarrhea by 1 mo of age. Initially, over 60% of the cows were fecal positive; within 6 months, all cows but I had become infected. The intermittent shedding of the organism and the eventual zero prevalence highlight the inappropriateness of extensive culling as an eradication strategy. Cultures of the bulk-tank milk filters were more sensitive than cultures of the bulk-tank milk samples at detecting S. Muenster. Two months after the index case, S. Muenster was cultured from the milk of 7.8% of the cows. Positive fecal or milk cultures were not associated with impaired health or production. The herd's milk was a zoonotic risk, but contact with infected animals was not. The organism spread easily between operations, likely via manure-contaminated clothing and footwear.