Zhang Li-Juan, Yang Jin-Tao, Chen Hai-Xin, Liu Wen-Zi, Ding Yi-Li, Chen Rui-Ai, Zhang Rong-Min, Jiang Hong-Xia
Zhaoqing Branch Center of Guangdong Laboratory for Lingnan Modern Agricultural Science and Technology, Zhaoqing 526000, China.
Guangdong Key Laboratory for Veterinary Pharmaceutics Development and Safety Evaluation, College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, China.
Antibiotics (Basel). 2023 May 25;12(6):961. doi: 10.3390/antibiotics12060961.
We determined the prevalence and molecular characteristics of -positive () isolated from duck-fish polyculture farms in Guangzhou, China. A total of 914 strains were isolated from 2008 duck and environmental samples (water, soil and plants) collected from four duck fish polyculture farms between 2017 and 2019. Among them, 196 strains were CTX-M-1G-positive strains by PCR, and 177 (90%) -producing strains were -positive. MIC results showed that the 177 -positive strains were highly resistant to ciprofloxacin, ceftiofur and florfenicol, with antibiotic resistance rates above 95%. Among the 177 strains, 37 strains carrying the F18:A-:B1 plasmid and 10 strains carrying the F33:A-:B- plasmid were selected for further study. Pulse field gel electrophoresis (PFGE) combined with S1-PFGE, Southern hybridization and whole-genome sequencing (WGS) analysis showed that both horizontal transfer and clonal spread contributed to dissemination of the gene among the . was located on different F18:A-:B1 plasmids with sizes between ~76 and ~173 kb. In addition, the presence of with other resistance genes (e.g., , , , , and ) on the same F18:A-:B1 plasmid may result in co-selection of resistance determinants and accelerate the dissemination of in . In summary, the F18:A-:B1 plasmid may play an important role in the transmission of in , and the continuous monitoring of the prevalence and transmission mechanism of in duck-fish polyculture farms remains important.
我们确定了从中国广州鸭鱼混养场分离出的CTX-M-15阳性大肠杆菌（E. coli）的流行情况和分子特征。2017年至2019年间，从四个鸭鱼混养场采集的2008份鸭及环境样本（水、土壤和植物）中，共分离出914株大肠杆菌菌株。其中，196株通过PCR检测为CTX-M-15阳性菌株，177株（90%）产ESBLs菌株为CTX-M-15阳性。药敏试验结果显示，这177株CTX-M-15阳性菌株对环丙沙星、头孢噻呋和氟苯尼考高度耐药，耐药率均高于95%。从这177株菌株中，选取了37株携带F18:A-:B1质粒和10株携带F33:A-:B-质粒的菌株进行进一步研究。脉冲场凝胶电泳（PFGE）结合S1-PFGE、Southern杂交和全基因组测序（WGS）分析表明，水平转移和克隆传播均促使CTX-M-15基因在大肠杆菌中传播。CTX-M-15位于大小约为76至173 kb的不同F18:A-:B1质粒上。此外，同一F18:A-:B1质粒上CTX-M-15与其他耐药基因（如blaTEM、blaSHV、blaOXA、tet(A)、tet(B)和aadA）共存，可能导致耐药决定簇的共选择，并加速CTX-M-15在大肠杆菌中的传播。综上所述，F18:A-:B1质粒可能在CTX-M-15在大肠杆菌中的传播中起重要作用，持续监测鸭鱼混养场中CTX-M-15的流行情况和传播机制仍然很重要。
