Antibiotic sensitivity.

Cow purulent catarrhal endometritis (PCE) is a common reproductive disorder in dairy cattle caused by bacterial infections. PCE impacts fertility, milk production, and animal health. Therapeutic approaches include systemic or intrauterine antibiotics. Unfortunately, the overuse of antibiotics in treating PCE drives the emergence of antibiotic-resistant bacteria, making infections difficult to treat and increasing food safety concerns due to antibiotic residues remaining in milk and meat products, posing health risks to consumers. Antimicrobial nanomaterials, particularly silver nanoparticles (AgNPs), provide an efficient alternative to combat multi-resistant bacteria, and the synergistic activity of AgNPs and antibiotics has been well documented, making the treatments of bacterial infections more efficient. Here, a comparative study is shown applying Argovit-C (AgNPs) and Enrocide as therapeutics for treating PCE in cattle. Intrauterine application of Argovit-C reduces the recovery time of cattle in comparison with Enrocide treatment as well as increases the sensitivity to antibiotics of Escherichia coli isolates from cervical canal secretion samples of diseased cattle. The increased sensitivity was found to 24 antibiotics, including aminoglycosides, fluoroquinolones, tetracyclines, penicillins, cephalosporins, macrolides, polymyxin, rifampicin, and chloramphenicol. The increased sensitivity was much higher for those bacteria that did not show an active efflux effect. Furthermore, Argovit-C reduced the acquisition of blaDHA and blaGES resistance genes in E. coli, as well as the number of bacterial isolates without efflux effect. Overall, this translational study performed in 300 cows demonstrates the ability of Argovit-C AgNPs to combat bacterial infections, favoring an increase in bacterial susceptibility to antibiotics and reducing their ability to acquire antibiotic multi-resistant genes.

奶牛化脓性卡他性子宫内膜炎（PCE）是奶牛常见的细菌性生殖系统疾病，可对奶牛的繁殖性能、产奶量及动物健康造成不良影响。其临床治疗手段包括全身给药或宫腔内施用抗生素。然而，PCE治疗中抗生素的过度使用会催生抗生素耐药菌，导致感染难以治愈；同时，奶与肉制品中残留的抗生素会引发食品安全隐患，威胁消费者健康。抗菌纳米材料，尤其是银纳米颗粒（AgNPs），为对抗多重耐药菌提供了高效替代方案，且AgNPs与抗生素的协同抗菌活性已得到充分证实，可有效提升细菌感染的治疗效率。本研究开展了一项对照试验，评估Argovit-C（AgNPs）与Enrocide用于治疗奶牛PCE的疗效。结果显示，宫腔内施用Argovit-C相较于Enrocide治疗，可缩短奶牛的康复周期，同时能提升从患病奶牛宫颈管分泌物样本中分离得到的大肠杆菌对各类抗生素的敏感性。这种敏感性提升覆盖24种抗生素，包括氨基糖苷类、氟喹诺酮类、四环素类、青霉素类、头孢菌素类、大环内酯类、多粘菌素、利福平和氯霉素。对于未表现出主动外排效应的大肠杆菌，其敏感性提升更为显著。此外，Argovit-C可减少大肠杆菌中blaDHA与blaGES耐药基因的携带情况，同时降低无主动外排效应的细菌分离株数量。总体而言，这项在300头奶牛中开展的转化研究证实，Argovit-C银纳米颗粒能够有效对抗细菌感染，可提升细菌对抗生素的敏感性，并降低细菌获得多重抗生素耐药基因的能力。