A large potentiation effect of serum on the invitro potency of tulathromycin against Mannheimia haemolytica and Pasteurella multocida
A large potentiation effect of serum on the invitro potency of tulathromycin against Mannheimia haemolytica and Pasteurella multocida
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DOI：
10.1111/jvp.12372
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发表时间：
2017-10-01
影响因子：
1.3
通讯作者：
Toutain, P. -L.
中科院分区：
文献类型：
--
作者：
Lees, P.;Illambas, J.;Toutain, P. -L.
研究了泰拉霉素对溶血性支原体和多杀性巴斯德菌的抗菌特性。建立了每种微生物6株的体外抗菌活性指标，即最小抑菌浓度（MIC）、最小杀菌浓度（MBC）和时间-杀灭曲线。在两种生长培养基：Mueller-Hinton肉汤（MHB）和小牛血清中测量每个指标。结果表明，血清MIC和MBC明显低于MHB。MHB：血清MIC比为47：1（溶血性M.haemolytica）和53：1（多杀性P.multocida）。对于血清和MHB，pH值的调整导致碱性条件下的效力高于酸性条件下的效力。泰拉霉素MIC受接种物计数大小的影响，初始计数高时是初始计数低时的4.0- 7.7倍。得出的结论是，为了确定治疗使用的剂量，应在生物液体如血清中获得泰拉霉素的药效学数据。据推测，根据国际推荐标准进行的肉汤中MIC的体外测量，作为估计泰拉霉素体内效价的基础可能会产生误导。
The antimicrobial properties of tulathromycin were investigated for M.haemolytica and P.multocida. Three invitro indices of antimicrobial activity, minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC) and time-kill curves, were established for six isolates of each organism. Each index was measured in two growth media: Mueller-Hinton broth (MHB) and calf serum. It was shown that MICs and MBCs were markedly lower in serum than in MHB. MHB:serum ratios for MIC were 47:1 (M.haemolytica) and 53:1 (P.multocida). For both serum and MHB, adjustment of pH led to greater potency at alkaline compared to acid pH. Tulathromycin MIC was influenced by size of inoculum count, being 4.0- to 7.7-fold greater for high compared to low initial counts. It was concluded that for the purpose of determining dosages for therapeutic use, pharmacodynamic data for tulathromycin should be derived in biological fluids such as serum. It is hypothesized that invitro measurement of MIC in broth, conducted according to internationally recommended standards, may be misleading as a basis for estimating the invivo potency of tulathromycin.