PDF(Pubmed)
Abstract：
The long-term stability of antibiotics in culture media remains underexplored in scientific literature. This study evaluated the stability of eight distinct antibiotic stock solutions-amoxicillin, cefotaxime, neomycin, oxytetracycline, florfenicol, enrofloxacin, colistin, and potentiated sulfonamide-and their 10-fold dilution series in tryptone soy broth (TSB) at 37 °C, over 12 days. Samples were collected immediately after preparation and on days 1, 2, 5, 7, 9, and 12, with active substance concentrations measured using ultra-high-performance liquid chromatography (UHPLC) coupled with mass spectrometry. The results indicated that among the ultrapure water stock solutions, neomycin, florfenicol, and potentiated sulfonamide maintained stability (>95%). Within the culture medium, florfenicol showed consistent stability (100%) throughout the study, potentiated sulfonamide experienced minor degradation (>85%), and neomycin underwent significant degradation. Amoxicillin, oxytetracycline, and colistin displayed considerable degradation in both solution types but were more stable in ultrapure water solutions. The stability of cefotaxime and enrofloxacin in ultrapure water solutions and in the medium was very similar when compared; however, 3.6% of the former and 88.7% of the latter remained detectable by day 12. These findings are crucial for minimum inhibitory concentration (MIC) assessments, especially in minimum bactericidal concentration (MBC) studies, and in experiments concerning long-term evolution and co-selection. This study underscores the necessity of stability assessments in culture media to validate future experimental outcomes.
摘要：
在科学文献中，抗生素在培养基中的长期稳定性仍未得到充分研究。这项研究评估了八种不同的抗生素储备溶液-阿莫西林的稳定性，头孢噻肟,新霉素,土霉素,氟苯尼考,恩诺沙星,粘菌素,并在37°C的胰蛋白tone大豆肉汤（TSB）中增强了磺酰胺及其10倍稀释系列，超过12天。在制备后立即和在第1、2、5、7、9和12天收集样品,使用超高效液相色谱(UHPLC)结合质谱测定活性物质浓度。结果表明，在超纯水原液中，新霉素,氟苯尼考,和强化磺酰胺保持稳定性(>95%)。在培养基中，氟苯尼考在整个研究中表现出一致的稳定性(100%)，强化磺酰胺经历轻微降解(>85%),和新霉素经历了显著降解。阿莫西林,土霉素,粘菌素在两种溶液中都显示出相当大的降解，但在超纯水溶液中更稳定。比较时，头孢噻肟和恩诺沙星在超纯水溶液和培养基中的稳定性非常相似；然而，前者的3.6%和后者的88.7%在第12天仍可检测到。这些发现对于最低抑制浓度（MIC）评估至关重要，特别是在最低杀菌浓度（MBC）研究中，以及关于长期进化和共同选择的实验。这项研究强调了在培养基中进行稳定性评估以验证未来实验结果的必要性。
