Assessment of temporal pattern of antimicrobial usage in commercial broiler farms in Cumilla, Bangladesh

Abstract

Occurrence of infectious poultry disease is one of the main constraints of Bangladesh’s growing commercial poultry sector which leads to misuse of antimicrobials for prophylactic and therapeutic purposes. Antimicrobial usage (AMU) in food-producing animals is a possible factor promoting antimicrobial resistance in both veterinary and human health sectors. A longitudinal study was therefore conducted to evaluate antimicrobial usage in the broiler production period on 40 commercial exotic small- to medium-scale broiler farms in eight sub-districts (Upazilla) of Cumilla, Bangladesh from January to March 2020. Farms were chosen purposively. Antimicrobial drug usage data was collected through over phone communication (every day) and repeated farm visit (at 3 days interval). Demographic and management data were obtained through a structured questionnaire for farmer as well as through farm observation. Descriptive analysis was carried out by using STATA-14. Flock-level AMU was characterized using qualitative and quantitative approach. All broiler farms used antimicrobials (AMs) and diverse AMU patterns were identified as 154 treatment courses (median 4; 95% CI: 3.4-4.5) of AM were administered in the studied broiler farms. AMs were used for prevention of disease or disease conditions by all but one farm. AMs were administered in the farms for prophylaxis (n=74, 48.1%), therapeutics (n=68, 44.2%), growth promotion (n=1, 0.7%), prophylaxis and growth promotion (n=7, 4.6%) and both prophylaxis and therapeutics (n=4, 2.6%). Despite government rules, AMs were suggested and used without any veterinary consultation, mostly by dealers and farmers. Descriptive AMU analysis provided the following results: 1) of the 154 total antimicrobial courses, fluoroquinolones were the most commonly (n=44, 28.6%) used AM group; followed by penicillins (n=29, 18.8%), tetracyclines (n=12, 7.8%) and sulfonamide-coccidiostats (n= 12, 7.8%). Chosen quantitative metrics yielded the following results: 1) calculated total AMU (according to milligrams per population correction unit (mg/PCU) metric) was 130.9 mg/PCU. Farm level median mg/PCU was 98.2 mg/PCU (range 4.4mg/PCU to 618.9 mg/PCU). Penicillins (29.5mg/PCU), fluoroquinolones (24.8mg/PCU) and sulfonamide-coccidiostat mixed preparations (13.5mg/PCU) were the most commonly used AM according to this metrics. 2) Total 221.4 number of defined daily dose per population correction unit (nDDD/PCU) (farm level median 3.1, range 0.3 to 21.7, 95% CI: 3.7-7.3) and 49 number of defined course dose per population correction unit (nDCD/PCU) (median 1.1, range xiii 0.5 to 4.6, 95% CI: 0.8-1.6) of AM were used in the studied farms. Depending on the metrics chosen, variations were observed in temporal trends (change of mg/PCU in different weeks of production period was evidently steadier in curves than crude amount) and relative ranking (of descriptive, weight-based and dose-based-metrics). When using frequency measures, top three AMs were amoxicillin, enrofloxacin and doxycycline. Dose-based metrics, nDDD/PCU and nDCD/PCU showed the same top three AM patterns. However, while using mg/PCU metrics, the top three AMs used were amoxicillin, tylosin and neomycin. The choice of the AMU metric is an important consideration for any AMU reporting. Understanding the effects of parameters used in AMU reporting would help in a better reporting and would allow stakeholders to understand better the impacts of AMU and formation and evaluation of AMU reduction strategies. This study implied a high level of AMU, especially medically important AMs in broiler farms, and it requires immediate intervention. Rules and regulations should be strictly followed in trade of AMs. Continuous research works are needed to improve stewardship and provide better monitoring of AMU and subsequent antimicrobial resistance (AMR) situation. Awareness programs should be arranged for the farmers and relevant stakeholders on risk of indiscriminate AMU and AMR.