Research article - Peer-reviewed, 2020
Antimicrobial Resistance Patterns in Organic and Conventional Dairy Herds in SwedenSjostrom, Karin; Hickman, Rachel A.; Tepper, Viktoria; Olmos Antillon, Gabriela; Jarhult, Josef D.; Emanuelson, Ulf; Fall, Nils; Sternberg Lewerin, Susanna
AbstractMonitoring antimicrobial resistance (AMR) and use (AMU) is important for control. We used Escherichia coli from healthy young calves as an indicator to evaluate whether AMR patterns differ between Swedish organic and conventional dairy herds and whether the patterns could be related to AMU data. Samples were taken twice, in 30 organic and 30 conventional dairy herds. Selective culturing for Escherichia coli, without antibiotics and with nalidixic acid or tetracycline, was used to estimate the proportions of resistant isolates. Microdilution was used to determine the minimum inhibitory concentrations (MICs) for thirteen antimicrobial substances. AMU data were based on collection of empty drug packages. Less than 8% of the bacterial growth on non-selective plates was also found on selective plates with tetracycline, and 1% on plates with nalidixic acid. Despite some MIC variations, resistance patterns were largely similar in both periods, and between organic and conventional herds. For most substances, only a few isolates were classified as resistant. The most common resistances were against ampicillin, streptomycin, sulfamethoxazole, and tetracycline. No clear association with AMU could be found. The lack of difference between organic and conventional herds is likely due to a generally good animal health status and consequent low AMU in both categories.
Keywordsantibiotic; antibiotic resistance; livestock; antibiotic use; AMR; MDR; environment
2020, volume: 9, number: 11, article number: 834
Hickman, Rachel A.
Järhult, Josef D.
Uppsala University Hospital
Swedish University of Agricultural Sciences, Department of Biomedical Science and Veterinary Public Health
Sustainable Development Goals
SDG3 Good health and wellbeing
UKÄ Subject classification
URI (permanent link to this page)