Establishing defined daily doses (DDDs) for antimicrobial agents used in pigs, cattle and poultry in Japan and comparing them with European DDD values

Assessing trends in ectoparasiticidal drugs used to control ticks and flies in farm animals: A four-year analysis reveal differences between epidemiological zones at country level in Uruguay

The use of ectoparasiticides is a major concern in the control of parasites. In this study, we examined the trends and patterns of veterinary medicines use comparing between a high-risk epidemiological zone (HRZ) and a low-risk epidemiological zone (LRZ) for ectoparasites over a four-year period (2017-2020) at country level data. The objective of this study was to analyze the patterns of ectoparasiticide use in Uruguayan cattle, using the Anatomical Therapeutic Chemical Classification System for Veterinary Drugs (ATCvet) and dose indicators to consider regional variations in the animal population and production intensity. A total of 222 registered products classified as acaricides and/or insecticides based on 21 different active ingredients were grouped into 8 ATCvet level 4 categories. The annual consumption of active ingredients in ectoparasiticides averaged 40.6 tons. The total volume in the HRZ was 693 % higher than in the LRZ. The most sold ATCvet groups were Amidines (55.9 %), Pyrethrins/Pyrethroids (20.7 %), and Organophosphate Compounds (7 %). We calculated four different indicators with the resulting median values for entire country: 89.3 Technical Units per 1000 kg (IQR range of 10.5), 0.15 mg/kg of dosing biomass, 45.7 mg/ha of dose grazing area, and 3.09e+ 10 mg/LU/ha, respectively. Amidines were the most used group in the HRZ across all indicators, while Carbamates and Pyrethrins/Pyrethroids dominated in the LRZ. Cypermethrin, Amitraz, and Ethion were predominant in the HRZ, while Cypermethrin, Carbaryl, and Diazinon were common in the LRZ. The analysis of the four mixed Generalized Linear Models revealed significant differences in the use of veterinary medicines between zones with varying levels of epidemiological risk for parasitic diseases, with certain categories showing consistent patterns between indicators and zones. These results highlight the complexity of a veterinary medicine usage and the need for specialized strategies in veterinary medicine to address regional differences in the use of parasitic agents.

Establishing defined daily and course doses for antimicrobials used in Pakistani broilers to enable farm-level quantification and comparison of antimicrobial use

Monitoring antimicrobial use (AMU) is crucial, as it plays a key role in driving antimicrobial resistance (AMR). Animals account for a significant share of AMU, making it essential to accurately quantify AMU exposure at the species, farm, and country levels. In Pakistan, prophylactic use of antimicrobials remains common alongside therapeutic use. This study aimed to establish defined daily and course doses for both therapeutic and prophylactic use of antimicrobials in commercial broiler production in Pakistan. A list of antimicrobial products was compiled from the daily treatment records from 100 commercial broiler farms in Punjab, Pakistan. For each active substance (AS), a defined daily dose (DDDvetPK) was assigned for treatment, prevention or both, by averaging the recommended doses of all similar AS with the same administration route. A defined course dose (DCDvetPK) was calculated by multiplying the average recommended dose by the average treatment duration for each AS, based on the Summary of Product Characteristics (SmPC). A total of 41 AS, categorized into 17 antimicrobial classes, were identified from 139 antimicrobial products. The most frequently reported AS were colistin (polymyxins) at 15.9 %, amoxicillin (aminopenicillins) at 7.5 %, neomycin (aminoglycosides) at 7.3 %, enrofloxacin (fluoroquinolones) at 6.7 %, and tylosin (macrolides) at 6.4 % of the total treatments (n = 358) reported at farms. Notably, 51 % of AS were classified as critically important for human medicine by WHO. Among AS indicated for treatment in SmPC, the defined daily doses for Pakistan (DDDvetPK) varied substantially from the European Medicines Agency (EMA) values (DDDvet), with the top deviations being Tiamulin (+147.8 %), Sulfadimidine_TMP (+111.2 %), Flumequine (+88.6 %), Spiramycin (-87.8 %), and Tylosin (-84.3 %). This study presents a list of defined daily doses and defined course doses for AMU quantification in Pakistani broilers using dose-based indicators. The observed differences between Pakistani and EMA doses, and lack of EMA doses for preventive antimicrobials, suggest using Pakistani DDDvetPK values to quantify antimicrobial usage in Pakistan. A huge variation in recommended doses was reported in SmPC. There is an urgent need to establish a list of approved veterinary antimicrobials used in Pakistan, along with harmonization in recommended doses and maintenance of standardized SmPC by the drug regulatory authorities. Setting up a national-level list of defined daily doses is crucial to accurately monitor and quantify AMU.

Prevalence of Antibiotic-Resistant Escherichia coli Isolated from Beef Cattle and Dairy Cows in a Livestock Farm in Yamagata, Japan

Antimicrobials are used on livestock farms to treat and prevent infectious animal diseases and to promote the growth of livestock. We monitored the prevalence of antibiotic-resistant Escherichia coli (AR-EC) isolates from beef cattle (BC) and dairy cows (DCs) on a livestock farm in Yamagata, Japan. Fecal samples from 5 male BC and 10 male DCs were collected monthly from October 2022 to November 2023. In total, 152 and 884 E. coli isolates were obtained from the BC and DC fecal samples, respectively. Notably, 26 (17.1%) and 29 (3.3%) E. coli isolates in the BC and DC groups, respectively, were resistant to at least one antibiotic. The resistance rates to tetracycline, ampicillin, gentamicin, and chloramphenicol of the isolates were significantly higher than those to the other antimicrobials. The tetracycline resistance genes tetA (70.6%) in DCs and tetB (28%) in BC were identified, along with the blaTEM gene in ampicillin-resistant isolates (BC: 84.2%, DCs: 42.8%). Despite significant variations in the monthly detection rates of AR-EC isolated from BC and DCs throughout the sampling period, the judicious use of antimicrobials reduced the occurrence of AR-EC in both BC and DCs, thereby minimizing their release into the environment.

The association between farm-level antimicrobial usage and resistance of Staphylococcus spp., as the major genus isolated from aerosol samples, in Japanese piggeries

Bacteria are the dominant particulate matter in livestock houses and can threaten animal and public health. Antimicrobial resistance (AMR) is a crucial concern worldwide, and nationwide measures established based on the One Health approach are being implemented in many countries. This requires multidisciplinary perspectives and collaboration among the human, animal, and environmental sectors. However, information on the AMR risk in livestock house aerosol is limited, especially its association with antimicrobial usage (AMU). Therefore, this study was conducted to reveal the AMR profile of Staphylococcus, the major bacterial genus in the aerosol of the piggeries of Japanese farms, and the association between farm-level AMU and AMR. The investigation at 10 farrow-to-finish pig farms revealed that regardless of the sampling season and the piggery group, the resistance rate of isolated staphylococci for oxacillin, erythromycin, and lincomycin was more than 40% of the median and tended to be higher than that for other antimicrobials. The AMU adjusted by the defined daily dose (DDD-adjusted AMU) in the fattening piggery group was significantly higher than that in the sow piggery group (p < 0.05). Finally, for the fattening piggery group, the generalized linear mixed model revealed that the AMR rate for oxacillin, erythromycin, tetracycline, and chloramphenicol was positively associated with the corresponding class-based DDD-adjusted AMU of penicillins (odds ratio (OR) = 2.63, p = 0.03), macrolides (OR = 6.89, p = 0.0001), tetracyclines (OR = 2.48, p = 0.04), and amphenicols (OR = 3.22, p = 0.03), respectively. These significant positive associations observed in this study imply that the resistance rate for these antimicrobials may decrease by reducing the corresponding antimicrobials' use. In addition, the resistance rates for erythromycin and chloramphenicol also displayed a positive association with the AMU of antimicrobial classes other than macrolides and amphenicols, respectively. The mechanism underlying these phenomena is unclear; therefore, further evaluation will be needed. As limited studies have reported staphylococci in piggery aerosol and its AMR with quantitative AMU, these results based on on-farm investigations are expected to aid in establishing countermeasures for AMR of aerosol bacteria in pig farms.

Quantitative and qualitative analysis of antimicrobial usage and biosecurity on broiler and Sonali farms in Bangladesh

Antimicrobial use (AMU) is a major contributing factor to the rising threat of antimicrobial resistance (AMR) in human and animals. To control AMR, indiscriminate antibiotic use needs to be restricted, preventive measures such as biosecurity must be prioritized and proper action plans must be implemented. This study aimed to quantify and associate AMU and biosecurity status of broiler and Sonali farms in Bangladesh. Data on all antimicrobial treatments administered during a batch production cycle and antimicrobials purchased over a year were collected from 94 conventional broiler and 51 Sonali (cross-breed) farms from the northern and southeast regions of Bangladesh. Flock-level AMU was quantified using Treatment Incidence (TI) per 100 days based on the Defined Daily Dose (TI_DDDvet) expressing the number of days per 100 animal-days at risk that the flock receives a standard dose of antimicrobials. The biosecurity status (external and internal) of these farms was assessed by means of the Biocheck.UGent scoring system and the correlation between biosecurity and TI_DDDvet were assessed by Pearson's correlation coefficients. Median flock TI_DDDvet was 60 and 58 for broilers and Sonali flocks, indicating that the birds were treated around 60% and 58% of their lifetime with an antimicrobial dose, respectively. Minimum and maximum values of TI_DDDvet ranged from 18 -188 and 31-212 in broilers and Sonali, respectively. Fluoroquinolones, sulfonamides, tetracyclines and aminopenicillins were the most frequently used antimicrobial classes. The mean external and internal biosecurity scores were 39% and 61% for broilers and 44% and 61% for Sonali, respectively. There was a statistically significant difference in the external biosecurity score in broiler farms in the two regions (p ≤ 0.001), whereas, the internal biosecurity score was borderline not statistically significantly different (p = 0.065). The biosecurity score was negatively correlated with AMU in broiler and sonali farms both for external (R² =-0.38; -0.36) and internal biosecurity (R² =-0.33; -0.32), respectively. As most of the farmers treated their birds with antimicrobials for a very large part of the production, it could be concluded that there is a high overuse of antimicrobials both in broiler and Sonali poultry production in Bangladesh. This study also highlighted a low level of farm biosecurity practices. Overuse of antimicrobials and low level of biosecurity practice may be due to a lack of knowledge, ignorance, avoid loss and/or lack of monitoring by governmental agencies. Therefore, urgent action is required to increase awareness and biosecurity levels and to reduce AMU in these production systems.

Antimicrobial use and its association with the presence of methicillin-resistant staphylococci (MRS) and extended-spectrum beta-lactamases (ESBL)-producing coliforms in mastitic milk on dairy farms in the Chiba Prefecture, Japan

Food-producing animals, including dairy cattle, are potential reservoirs of antimicrobial resistance. However, there is limited data on antimicrobial use and the selection of resistant bacteria. Therefore, we investigated the association between antimicrobial use and resistance to mastitis pathogens using 2016 data from milk samples collected from cows with mastitis in 134 dairy farms in Chiba Prefecture, one of the principal dairy production prefectures in Japan. We recorded the antimicrobial use and isolation of methicillin-resistant staphylococci (MRS) and extended-spectrum beta-lactamase (ESBL)-producing coliforms (E. coli and Klebsiella spp.), and used the antimicrobial treatment incidence (ATI; the theoretical number of animals per 1000 animal-days subjected to antimicrobial treatment) to indicate antimicrobial use on each farm. The farms in which MRS or ESBL-producing coliforms were isolated from at least one mastitic milk sample were classified as antimicrobial resistance (AMR)-positive, and those in which neither MRS nor ESBL-producing coliforms were isolated were classified as AMR-negative. The AMR-positive farms showed a significantly higher ATI (median 45.17) than AMR-negative farms (median 38.40). The results indicate that high antimicrobial usage is associated with AMR in staphylococci and coliforms isolated from mastitic milk on dairy farms in Chiba Prefecture.

Evaluating the antimicrobial use on dairy farms in Chiba Prefecture in Japan using the antimicrobial treatment incidence, an indicator based on Japanese defined daily doses from 2014-2016

The use of antimicrobial agents in food-producing animals may lead to the emergence and spread of antimicrobial resistance in bacteria of animal origin. However, there is a paucity of data on the quantity of antimicrobials use on dairy farms in Japan. This study describes antimicrobial use on dairy farms from 1 January 2014 to 31 December 2016 in five administrative districts (central, eastern, western, southern and northern) of Chiba Prefecture. The use of antimicrobial agents in dairy cattle over these three years was evaluated in terms of the antimicrobial treatment incidence (ATI; theoretical number of animals per 1,000 animal-days subjected to antimicrobial treatment) using data collected from a total of 442 dairy farms in that prefecture. Our results revealed that the average ATI on these farms for these years ranged from 38.7 to 39.4 with no significant difference between years and that the average ATI for these administrative districts varied between 32.9 and 43.2 with a significant variation between some of the districts. Approximately 84% of antimicrobials were administered intramammarily, 13–14% by injection and 1–2% orally. Scenario analyses were performed to assess the effect of changes in some of the defined daily dose (DDDjp) values used to calculate the ATI. Our results revealed that the calculated ATI is considerably affected by the changes in the long-acting factor used for assigning the DDDjp values of intramammary products for dry cows and the way in which DDD values are assigned for combination products.

Evaluation of antimicrobial use in dairy cattle, beef cattle and broilers in Japan using dosage-based indicators

The sales amount of antimicrobials intended for use in dairy cattle, beef cattle and broilers from 2008 to 2019 was evaluated for each antimicrobial class and administration route using dosage-based indicators. Our results revealed that the antimicrobial sales amount sold for use in dairy cattle in 2019 in terms of total weight of active ingredient, the number of defined daily doses (DDDs) (theoretical amount of biomass subjected to antimicrobial treatment in a year) and the number of treatment days (TDs) (theoretical number of days of treatment that an animal is subjected to in a year) calculated using Japanese DDD values (DDDjp values) was 36,751 kg, 8,261,848,000 kg·days and 15.5 days, respectively. Likewise, the antimicrobial sales amount sold for use in beef cattle and broilers in 2019 in terms of these metrics was 33,403 kg, 3,928,248,000 kg·days and 3.61 days, and 69,773 kg, 2,947,848,000 kg·days and 10.66 days, respectively. There was a considerable difference between the number of DDDs calculated using DDDjp values and that calculated using European DDD values (DDDvet values) for antimicrobial products sold for use in dairy and beef cattle. Our results also revealed that the sales amount of some antimicrobials, such as cephalosporins and quinolones represented larger proportions when calculated using dosage-based indicators than when calculated using the weight of active ingredient. Considering that Japanese veterinarians and farmers are more likely to conform to the Japanese dosage recommendations rather than the European ones, these results indicate the need for using dosage-based metrics, in particular metrics based on Japanese dosages rather than European dosages.

Antimicrobial use on 74 Japanese pig farms in 2019: A comparison of Japanese and European defined daily doses in the field

Defined daily doses (DDD) have been established in human medicine to standardize the measurement of treatment in a population. In veterinary medicine, the European Medicine Agency published defined daily dose (DDDvet) values for antimicrobial agents used in food-producing animals in 2016. National defined doses (DDDjp) for antimicrobials used for pigs in Japan have recently been determined. The aim of this study was to compare the results of calculated antimicrobial use in the field using the DDDjp and DDDvet values. Data from 74 pig farms in Japan relative to antimicrobial use in 2019 was collected. The numbers of DDDs (the weight of biomass treated in kg-days) using DDDjp and DDDvet values for each farm and for different antimicrobial classes were compared. Associations between calculated numbers of DDDjp and DDDvet on farm level were investigated. In addition, differences in antimicrobial use were investigated between different production types of farms (farrowing, finishing and farrow-to-finish farms). Using DDDjp and DDDvet values, the aggregated number of DDDs for 74 farms were 4,099,188 and 2,217,085 respectively, with the former being larger by 1.85 times than the latter. The most frequently used antimicrobial class was penicillin regardless of whether DDDjp or DDDvet was used. The absence of DDDvet values for certain antimicrobial agents used in Japan and the differences in the number of DDDjps/PCU and DDDvets/PCU indicated the need for Japanese DDDs. The number of DDDs per kg population correction unit (PCU) per farm tended to be higher in farrowing farms than in farrow-to-finish farms and finishing farms, with no significant difference (P = 0.19).