Fecteau Marie-Eve, Fyock Terry L, McAdams Susan C, Boston Raymond C, Whitlock Robert H, Sweeney Raymond W
Department of Clinical Studies-New Bolton Center, School of Veterinary Medicine, University of Pennsylvania, Kennett Square, PA 19348, USA.
Am J Vet Res. 2011 Sep;72(9):1243-6. doi: 10.2460/ajvr.72.9.1243.
To evaluate the in vitro susceptibility of various field isolates of Mycobacterium avium subsp paratuberculosis (MAP) to gallium nitrate.
10 isolates of MAP, including 4 isolated from cattle, 2 isolated from bison, 1 isolated from an alpaca, and 3 isolated from humans.
The in vitro susceptibility to gallium nitrate was tested by use of broth culture with detection of MAP growth by means of a nonradiometric automated detection method. For each MAP isolate, a series of 7 dilutions of gallium nitrate (concentrations ranging from 200 to 1,000 μM) were tested. Gallium nitrate was considered to have caused 90% and 99% inhibition of the MAP growth when the time to detection for culture of the MAP stock solution and a specific concentration of gallium nitrate was delayed and was similar to that obtained for culture of the MAP stock solution (without the addition of gallium nitrate) diluted 1:10 and 1:100, respectively.
Gallium nitrate inhibited MAP growth in all 10 isolates. The susceptibility to gallium nitrate was variable among isolates, and all isolates of MAP were inhibited in a dose-dependent manner. Overall, the concentration that resulted in 90% inhibition ranged from < 200 μM for the most susceptible isolates to 743 μM for the least susceptible isolates.
Gallium nitrate had activity against all 10 isolates of MAP tested in vitro and could potentially be used as a prophylactic agent to aid in the control of MAP infections during the neonatal period.
评估不同的副结核分枝杆菌（MAP）现场分离株对硝酸镓的体外敏感性。
10株MAP分离株，包括4株从牛身上分离得到的、2株从美洲野牛身上分离得到的、1株从羊驼身上分离得到的以及3株从人类身上分离得到的。
采用肉汤培养法并通过非放射性自动检测方法检测MAP生长情况，以此来测试硝酸镓的体外敏感性。对于每一株MAP分离株，测试了一系列7种浓度的硝酸镓（浓度范围为200至1000μM）。当MAP储备液和特定浓度硝酸镓培养物的检测时间延迟，且分别与稀释1:10和1:100的MAP储备液（不添加硝酸镓）培养物的检测时间相似时，硝酸镓被认为对MAP生长产生了90%和99%的抑制作用。
硝酸镓抑制了所有10株分离株的MAP生长。不同分离株对硝酸镓的敏感性存在差异，所有MAP分离株均呈现剂量依赖性抑制。总体而言，导致90%抑制的浓度范围从最敏感分离株的<200μM到最不敏感分离株的743μM。
硝酸镓在体外对所有10株测试的MAP分离株均有活性，并且有可能用作预防剂，以帮助控制新生儿期的MAP感染。
