Impact of a Statewide Livestock Antibiotic Use Policy on Resistance in Human Urine Isolates: A Synthetic Control Analysis
Environmental health perspectives
BACKGROUND: On 1 January 2018, California implemented Senate Bill 27 (SB27), banning, for the first time in the United States, routine preventive use of antibiotics in food-animal production and any antibiotic use without a veterinarian's prescription. OBJECTIVES: Our objective was to assess whether SB27 was associated with decreased antimicrobial resistance among isolated from human urine. METHODS: We used U.S. nationwide monthly state-level data from BD Insights Research Database (Becton, Dickinson, and Co.) spanning 1 January 2013 to 30 June 2021 on antibiotic-resistance patterns of 30-d nonduplicate isolated from urine. Tested antibiotic classes included aminoglycosides, extended-spectrum cephalosporins (ESC), fluoroquinolones, and tetracyclines. Counts of tested and not-susceptible (resistant and intermediate, hereafter resistant) urine isolates were available by sex, age group (, year), month, and state. We applied a synthetic control approach to estimate the causal effect of SB27 on resistance patterns. Our approach created a synthetic California based on a composite of other states without the policy change and contrasted its counterfactual postpolicy trends with the observed postpolicy trends in California. FINDINGS: We included urine isolates, 90% among women, across 33 states. From 2013 to 2017, the median (interquartile range) resistance percentages in California were 11.9% (7.4, 17.6), 13.8% (5.8, 20.0), 24.6% (9.6, 36.4), 7.9% (2.1, 13.1), for aminoglycosides, ESC, fluoroquinolones, and tetracyclines, respectively. SB27 was associated with a 7.1% reduction in ESC resistance (-value for joint null: ), but no change in resistance to aminoglycosides, fluoroquinolones, or tetracyclines. DISCUSSION: Further research is needed to determine the role of SB27 in the observed reduction in ESC resistance in human populations, particularly as additional states implement similar legislation. https://doi.org/10.1289/EHP11221.
Casey, Joan A.; Tartof, Sara Y.; Davis, Meghan F.; Nachman, Keeve E.; Price, Lance; Liu, Cindy; Yu, Kalvin; Gupta, Vikas; Innes, Gabriel K.; Tseng, Hung Fu; Do, Vivian; Pressman, Alice R.; and Rudolph, Kara E., "Impact of a Statewide Livestock Antibiotic Use Policy on Resistance in Human Urine Isolates: A Synthetic Control Analysis" (2023). GW Authored Works. Paper 2456.
Environmental and Occupational Health