Hosoi Yuta, Kawanishi Michiko, Harada Saki, Kumakawa Mio, Matsuda Mari, Sekiguchi Hideto
Veterinary AMR Center, National Veterinary Assay Laboratory, Ministry of Agriculture, Forestry and Fisheries, Tokyo 185-8511, Japan.
Int J Mol Sci. 2024 Dec 23;25(24):13723. doi: 10.3390/ijms252413723.
To investigate fosfomycin resistance rates in cattle across Japan, we carried out susceptibility tests. To identify the genes contributing to fosfomycin resistance, we performed whole-genome sequencing on the fosfomycin-resistant strains. were sampled from healthy cattle ( = 292, combined total from 2017, 2020, 2021, and 2022) and diseased cattle ( = 73, from 2021 to 2022). spp. were obtained from diseased cattle ( = 74 from 2021 to 2022). These samples originated from different and non-duplicated farms. The MICs to fosfomycin were measured using an agar dilution method with a breakpoint of 256 μg/mL. We conducted whole-genome sequencing with a MiSeq, followed by in silico analysis of the acquired draft genomes. The resistance rates were 0.3% (95% CI [0-1.9%]), 6.8% (95% CI [2.3-15.3%]), and 1.4% (95% CI [0-7.3%]). The gene was detected in five out of six fosfomycin-resistant strains and one spp. strain. The fosfomycin-resistant spp. strain also has a gene. One strain showed resistance to fosfomycin without having the gene, and with the mutations of , , and , and with the existence of efflux pumps. The nationwide scale of resistance rates to fosfomycin in isolated from healthy and diseased cattle and that of spp. from diseased cattle were revealed for the first time, and the resistance rates were low. In addition, genes linked to the mechanism of fosfomycin resistance were identified.
为调查日本全国牛群中磷霉素耐药率，我们进行了药敏试验。为鉴定导致磷霉素耐药的基因，我们对磷霉素耐药菌株进行了全基因组测序。样本取自健康牛（n = 292，为2017年、2020年、2021年和2022年的合并总数）和患病牛（n = 73，来自2021年至2022年）。大肠杆菌菌株取自患病牛（n = 74，来自2021年至2022年）。这些样本来自不同且无重复的农场。采用琼脂稀释法测定磷霉素的最低抑菌浓度，折点为256μg/mL。我们使用MiSeq进行全基因组测序，随后对获得的草图基因组进行计算机分析。耐药率分别为0.3%（95%可信区间[0 - 1.9%]）、6.8%（95%可信区间[2.3 - 15.3%]）和1.4%（95%可信区间[0 - 7.3%]）。在6株磷霉素耐药大肠杆菌菌株和1株大肠杆菌属菌株中检测到fosA基因。该磷霉素耐药大肠杆菌属菌株还具有mph(A)基因。1株大肠杆菌菌株对磷霉素耐药，但未携带fosA基因，存在gyrA、parC、mdf(A)和emrB突变，且存在外排泵。首次揭示了从健康和患病牛分离出的大肠杆菌以及从患病牛分离出的大肠杆菌属在全国范围内对磷霉素的耐药率，且耐药率较低。此外，还鉴定了与磷霉素耐药机制相关的基因。
