Don Whitley Scientific Ltd., Shipley, West Yorkshire, BD177SE, UK.
Vet Microbiol. 2011 Aug 5;151(3-4):409-12. doi: 10.1016/j.vetmic.2011.03.016. Epub 2011 Mar 21.
Tiamulin activity was measured against 19 UK field isolates of Actinobacillus pleuropneumoniae collected between 2003 and 2009 and the type strain ATCC 27090 as a control, with the intention of comparing broth with serum as growth media. Broth microdilution MIC/MBC tests were performed in accordance with the Clinical and Laboratory Standards Institute (CLSI) guideline M31-A3, in 'Veterinary Fastidious Medium' (VFM) (supplemented Mueller-Hinton broth at pH 7.3) and in 100% swine serum. For improved precision, a modified, overlapping doubling-dilution series was used (tiamulin concentration range 0.3-72 μg/ml). The MBC was reported as the lowest concentration producing a 99.9% reduction in bacterial density in the sub-cultured well contents, relative to the starting inoculum. The mean MBC/MIC ratio for tiamulin against A. pleuropneumoniae in VFM was low (1.74:1), even though tiamulin is classed as a bacteriostatic drug. Only three of the 19 isolates and the reference strain grew in 100% serum and their MICs were higher than those determined in VFM. It is postulated that this difference was due to differences in pH of the matrices or binding of tiamulin to serum proteins or a combination of both factors.
替米考星活性测定使用了 19 株英国胸膜肺炎放线杆菌分离株，这些分离株于 2003 年至 2009 年采集，作为对照的是模式菌株 ATCC 27090，其目的是比较肉汤和血清作为生长培养基。肉汤微量稀释 MIC/MBC 试验按照临床和实验室标准协会（CLSI）指南 M31-A3 进行，在“兽医难培养介质”（VFM）（补充 pH7.3 的 Mueller-Hinton 肉汤）和 100%猪血清中进行。为了提高精度，使用了改进的、重叠的两倍稀释系列（替米考星浓度范围为 0.3-72μg/ml）。MBC 被报道为在亚培养孔内容物中相对于起始接种物降低细菌密度 99.9%的最低浓度。替米考星在 VFM 中对胸膜肺炎放线杆菌的 MBC/MIC 比值较低（1.74:1），尽管替米考星被归类为抑菌药物。在 19 株分离株和参考株中，只有 3 株在 100%血清中生长，其 MIC 高于在 VFM 中确定的 MIC。据推测，这种差异是由于基质的 pH 差异或替米考星与血清蛋白的结合或这两个因素的结合所致。
