Liu Kaidi, Liu Junqi, Su Yuting, Wang Minge, Long Tengfei, Fang Liangxing, Zhou Yufeng, Sun Jian, Liao Xiaoping
National Risk Assessment Laboratory for Antimicrobial Resistance of Animal Original Bacteria, South China Agricultural University, Guangzhou, P. R. China.
School of Agricultural Science and Engineering, Liaocheng University, No.1 Hunan Road, Liaocheng, Shandong, 252000, China.
BMC Vet Res. 2025 May 15;21(1):343. doi: 10.1186/s12917-025-04808-7.
β-lactam antibiotics represent the most widely utilized class of antimicrobial agents in livestock and poultry breeding. However, the effects of β-lactam antibiotics on conjugation transfer of IncI2 plasmids and the homeostasis of the mouse intestinal microbiota have not been thoroughly investigated.
The results revealed that the transfer of IncI2 plasmid was the highest for intra-specific E. coli and inter-specific transfer to Salmonella and K. pneumoniae occurred at much lower levels in the absence of β-lactam antibiotic selective pressure. Furthermore, inter-species and intra-species transfer of IncI2 plasmid was enhanced in the presence of sub-MIC levels of amoxicillin/clavulanate and cephalexin whereas ampicillin promoted only inter-species transfer. These results were consistent with in vivo observations where amoxicillin/clavulanate and cephalexin but not ampicillin promoted conjugation. Meanwhile, the intestinal microbiota was also disturbed following antibiotic treatment and Proteobacteria abundance increased while Bacteroides decreased. The gut microbiota could also be partially restored to initial levels after antibiotic cessation for 14 days.
These findings highlight the potential risk of β-lactam antibiotics in promoting the spread of resistance plasmids and causing disruption to the intestinal microbiota.
β-内酰胺类抗生素是畜禽养殖中使用最广泛的一类抗菌剂。然而，β-内酰胺类抗生素对IncI2质粒接合转移及小鼠肠道微生物群稳态的影响尚未得到充分研究。
结果显示，在无β-内酰胺类抗生素选择压力的情况下，IncI2质粒在种内大肠杆菌间的转移率最高，向沙门氏菌和肺炎克雷伯菌的种间转移率则低得多。此外，在亚抑菌浓度的阿莫西林/克拉维酸和头孢氨苄存在的情况下，IncI2质粒的种间和种内转移均增强，而氨苄西林仅促进种间转移。这些结果与体内观察结果一致，即阿莫西林/克拉维酸和头孢氨苄可促进接合，而氨苄西林则不能。同时，抗生素治疗后肠道微生物群也受到干扰，变形菌门丰度增加而拟杆菌门减少。停用抗生素14天后，肠道微生物群也可部分恢复到初始水平。
这些发现突出了β-内酰胺类抗生素在促进耐药质粒传播及破坏肠道微生物群方面的潜在风险。
