Mateu-de-Antonio E M, Martín M
Unit of Infectious Diseases and Epidemiology, Veterinary Faculty, Universitat Autònoma de Barcelona, Bellaterra, Spain.
Vet Microbiol. 1995 Jun;45(1):1-10. doi: 10.1016/0378-1135(94)00122-d.
In vitro efficacy of tetracyclines, aminoglycosides, fluoroquinolones, rifampin and macrolides and their combinations against four Brucella canis and two B. melitensis strains isolated from dogs was evaluated by means of inhibition tests: minimal inhibitory concentration (MIC) and fractional inhibitory concentrations (FIC) and by bactericidal tests: minimal bactericidal concentrations (MBC) and kill-time experiments. In inhibition studies, tetracyclines showed the lowest MICs of all compounds tested (0.06-0.50 mg/l). However, doxycycline did not inhibit growth of B. canis D-519 strain at concentrations lesser than 1 mg/l. Most strains were resistant to macrolides. Chequerboard MIC titrations showed synergy between enrofloxacin and aminoglycosides against B. canis RM 6/66 reference strain and between doxycycline and streptomycin against B. canis D-519 strain. Combinations of tetracyclines and aminoglycosides were at the limit of synergy for B. canis RM 6/66 strain (FIC = 0.56). Combination of doxycycline and rifampin seemed to be antagonistic against B. canis M-strain (FIC = 3). Other combinations studied were indifferent or additive against all other strains. In bactericidal studies, aminoglycosides, fluoroquinolones and rifampin showed bactericidal activity at 1-4 x MIC but tetracyclines or macrolides did not kill brucellae below 8 x MIC. Results of kill-time experiments indicated that streptomycin was the antimicrobial agent tested which more rapid killed brucellae. In most cases, doxycycline did not kill brucellae in 96 h of incubation. Which using rifampin alone, some inocula of B. canis strains RM 6/66, D-519 and M- showed regrowth after 24 h of incubation. Retesting of these regrowing brucellae showed an increased MIC indicating development of phenotypic resistance. Testing of antimicrobial combinations in kill-time experiments indicated synergy between enrofloxacin and streptomycin and antagonism between rifampin and doxycycline both for B. canis RM 6/66 strain.
通过抑制试验（最小抑菌浓度（MIC）和部分抑菌浓度（FIC））以及杀菌试验（最小杀菌浓度（MBC）和杀菌时间实验），评估了四环素、氨基糖苷类、氟喹诺酮类、利福平和大环内酯类及其组合对从犬分离出的4株犬布鲁氏菌和2株羊布鲁氏菌菌株的体外效力。在抑制研究中，四环素在所有测试化合物中显示出最低的MIC（0.06 - 0.50mg/l）。然而，强力霉素在浓度低于1mg/l时未抑制犬布鲁氏菌D - 519菌株的生长。大多数菌株对大环内酯类耐药。棋盘式MIC滴定显示恩诺沙星与氨基糖苷类对犬布鲁氏菌RM 6/66参考菌株有协同作用，强力霉素与链霉素对犬布鲁氏菌D - 519菌株有协同作用。四环素与氨基糖苷类的组合对犬布鲁氏菌RM 6/66菌株处于协同作用的极限（FIC = 0.56）。强力霉素与利福平的组合对犬布鲁氏菌M菌株似乎有拮抗作用（FIC = 3）。研究的其他组合对所有其他菌株无作用或为相加作用。在杀菌研究中，氨基糖苷类、氟喹诺酮类和利福平在1 - 4倍MIC时显示出杀菌活性，但四环素或大环内酯类在低于8倍MIC时不能杀死布鲁氏菌。杀菌时间实验结果表明，链霉素是测试的抗菌剂中杀灭布鲁氏菌最快的。在大多数情况下，强力霉素在孵育96小时内未杀死布鲁氏菌。单独使用利福平时，犬布鲁氏菌菌株RM 6/66、D - 519和M的一些接种物在孵育24小时后出现再生长。对这些再生长的布鲁氏菌重新测试显示MIC增加，表明出现了表型耐药。在杀菌时间实验中测试抗菌组合表明，恩诺沙星与链霉素对犬布鲁氏菌RM 6/66菌株有协同作用，利福平与强力霉素有拮抗作用。
