Section for Animal Welfare and Disease Control, Department of Veterinary and Animal Sciences, Copenhagen University, Grønnegårdsvej 8, 1870, Frederiksberg C, Denmark.
National Food Institute, DTU Technical University of Denmark, Kemitorvet Building 204, 2800, Lyngby, Denmark.
Sci Rep. 2021 Feb 11;11(1):3527. doi: 10.1038/s41598-021-83228-7.
We caught stable- and house flies on a Danish LA-MRSA positive pig farm. Stable- and house flies were housed together and culled over time to test for the presence of live LA-MRSA bacteria at 24 h intervals to establish the length of time for which LA-MRSA can persist on flies. On average, 7% of stable flies and 27% of house flies tested positive for LA-MRSA immediately upon removal from the farm. LA-MRSA prevalence decreased over time and estimates based on a Kaplan-Meier time-to-event analysis indicated that the probability of a stable- or house fly testing positive for LA-MRSA was 5.4% and 7.8% after 24 h, 3.5% and 4.3% after 48 h, 3.1% and 2.2% after 72 h and 0.4% and 0% after 96 h of removal from the pig farm, respectively. Simultaneously, we found that caged cultivated house flies became carriers of LA-MRSA, without direct contact with pigs, in the same proportions as wild flies inside the farm. We provide distance distributions of Danish pig farms and residential addresses as well as the calculated maximum dispersal potentials of stable- and house flies, which suggest that there is a potential for stable- and house flies dispersing live LA-MRSA bacteria into the surrounding environment of a pig farm. This potential should therefore be considered when modelling the spread between farms or the risk posed to humans living in close proximity to LA-MRSA pig farm sources.
我们在丹麦携带 LA-MRSA 的阳性猪场捕获了厩蝇和家蝇。厩蝇和家蝇被关在一起，随着时间的推移被淘汰，以测试 LA-MRSA 活菌在 24 小时间隔内的存在时间，以确定 LA-MRSA 在苍蝇上持续存在的时间。平均而言，立即从农场取出时，有 7%的厩蝇和 27%的家蝇对 LA-MRSA 呈阳性。LA-MRSA 的流行率随时间下降，基于 Kaplan-Meier 时间事件分析的估计表明，在 24 小时后，厩蝇或家蝇检测到 LA-MRSA 的概率为 5.4%和 7.8%，在 48 小时后为 3.5%和 4.3%，在 72 小时后为 3.1%和 2.2%，在从猪场取出 96 小时后分别为 0.4%和 0%。同时，我们发现笼养的家养家蝇在没有与猪直接接触的情况下，成为 LA-MRSA 的携带者，其携带比例与农场内野生蝇相同。我们提供了丹麦猪场和住宅地址的距离分布，以及厩蝇和家蝇的最大扩散潜力的计算结果，这表明厩蝇和家蝇有将活的 LA-MRSA 细菌扩散到猪场周围环境的潜力。因此，在对农场之间的传播或生活在与 LA-MRSA 猪场来源密切相关的人类所面临的风险进行建模时，应考虑这一潜力。
