Veterinary Diagnostic & Production Animal Medicine, Iowa State University, College of Veterinary Medicine, 1600 South 16th St., Ames, IA 50011, USA.
Vet Microbiol. 2012 Jul 6;158(1-2):104-8. doi: 10.1016/j.vetmic.2012.02.002. Epub 2012 Feb 11.
Mycoplasma hyosynoviae is a common agent responsible for polyarthritis leading to decreased production in swine herds worldwide. Antimicrobial agents are used to combat infections; however breakpoints for M. hyosynoviae have not yet been established. A number of methods have previously been utilized to analyze minimum inhibitory concentrations (MICs) for antibiotics against M. hyosynoviae; however these techniques as currently described are not easily standardized between laboratories. A dry microbroth dilution method was conducted to compare the minimum inhibitory concentrations (MICs) for 18 antibiotics, representative of different classes, against 24 recent isolates (23 field isolates and the type strain) of M. hyosynoviae. The MICs were determined using standard, commercially available 96-well Sensititre(®) plates containing various freeze-dried antibiotics at a range of concentrations appropriate to their potency. Clindamycin (CLI), a lincosamide antibiotic, showed the highest activity and most consistent inhibition for all isolates with an MIC(50) of ≤ 0.12 μg/ml. Tiamulin (TIA), a pleuromutilin derivative, exhibited an MIC(50) of ≤ 0.25 μg/ml. The isolates had similar levels of susceptibility to the quinolones, enrofloxacin (ENRO) and danofloxacin (DANO), exhibiting an MIC(50) of 0.25 μg/ml and 0.5 μg/ml, respectively. For the macrolides, the MIC(50) for tylosin (TYLT) and tilmicosin (TIL) was ≤ 0.25 μg/ml and ≤ 2 μg/ml respectively, but was ≤ 16 μg/ml for tulathromycin (TUL). For the aminoglycosides, the MIC(50) for gentamicin (GEN) was ≤ 0.5 μg/ml, while spectinomycin (SPE) and neomycin (NEO) had an MIC(50) of ≤ 4 μg/ml. The tetracyclines, oxytetracycline (OXY) and chlortetracycline (CTET) both had an MIC(50) of ≤ 2 μg/ml. Florfenicol (FFN) exhibited a MIC(50) of ≤ 1 μg/ml. All isolates were resistant to penicillin (PEN), ampicillin (AMP), ceftiofur (TIO), trimethoprim/sulfamethoxazole (SXT), and sulphadimethoxine (SDM) at all concentrations. Within the isolates tested, there was a range of sensitivity detected, with some isolates being overall more resistant while others appeared more susceptible. Further research is required to demonstrate how this MIC data correlates to clinical efficacy of the various antibiotics in the field.
滑液支原体是一种常见的病原体，可导致全球猪群出现多发性关节炎，从而导致产量下降。抗菌药物被用于治疗感染;然而，滑液支原体的药敏折点尚未确定。以前已经有多种方法用于分析抗生素对滑液支原体的最小抑菌浓度 (MIC)；然而，目前这些技术在实验室之间不容易标准化。采用干燥微量肉汤稀释法比较了 18 种抗生素（代表不同类别）对 24 株近期分离株（23 株田间分离株和模式株）的最小抑菌浓度 (MIC)。使用标准的、市售的 Sensititre(®)96 孔板进行 MIC 测定，该板含有各种冻干抗生素，浓度范围适合其效力。克林霉素（CLI）是一种林可酰胺类抗生素，对所有分离株均表现出最高的活性和最一致的抑制作用，MIC50≤0.12μg/ml。替米考星（TIA），一种截短侧耳素衍生物，MIC50≤0.25μg/ml。这些分离株对喹诺酮类药物恩诺沙星（ENRO）和达氟沙星（DANO）的敏感性相似，MIC50 分别为 0.25μg/ml 和 0.5μg/ml。对于大环内酯类药物，泰乐菌素（TYLT）和替米考星（TIL）的 MIC50≤0.25μg/ml 和≤2μg/ml，但替米考星（TUL）的 MIC50≤16μg/ml。对于氨基糖苷类药物，庆大霉素（GEN）的 MIC50≤0.5μg/ml，而大观霉素（SPE）和新霉素（NEO）的 MIC50≤4μg/ml。四环素类药物，土霉素（OXY）和金霉素（CTET）的 MIC50≤2μg/ml。氟苯尼考（FFN）的 MIC50≤1μg/ml。所有分离株对青霉素（PEN）、氨苄西林（AMP）、头孢噻呋（TIO）、磺胺二甲嘧啶/甲氧苄啶（SXT）和磺胺二甲氧嘧啶（SDM）在所有浓度下均具有耐药性。在所测试的分离株中，检测到敏感性范围，一些分离株总体上更耐药，而另一些分离株则更敏感。需要进一步研究以证明该 MIC 数据如何与田间各种抗生素的临床疗效相关。
