Wallace R J, Dalovisio J R, Pankey G A
Antimicrob Agents Chemother. 1979 Nov;16(5):611-4. doi: 10.1128/AAC.16.5.611.
Although recent studies have suggested that some antibacterial agents have good activity against the rapidly growing mycobacteria Mycobacterium fortuitum and Mycobacterium chelonei, an easily applicable method for susceptibility testing of clinical isolates is not yet available. We evaluated a disk diffusion method with Mueller-Hinton agar and 48-h readings with 59 strains of M. fortuitum and 11 strains of M. chelonei and compared the results to agar dilution susceptibilities for nine antimicrobial agents. All isolates were susceptible to 16 micrograms of amikacin or kanamycin per ml with minimum zone diameters of 14 and 18 mm, respectively. Amikacin inhibited 100% of isolates of M. fortuitum at 2 micrograms/ml, whereas 10 of 11 (91%) of M. chelonei strains had minimum inhibitory concentrations of 4.0 micrograms/ml or greater. Doxycycline and minocycline had almost identical activities, inhibiting 44% of strains at 4.0 micrograms/ml, and both allowed easy differentiation between susceptible and resistant strains by disk diffusion. Although most isolates of M. chelonei grew better on 7H10 agar, this media gave two- to eight-fold higher minimum inhibitory concentrations than were obtained with Mueller-Hinton agar. Disk diffusion susceptibility testing appears to be a simple and reliable means of predicting susceptibility results for M. fortuitum and most isolates of M. chelonei by the agar dilution method.
尽管最近的研究表明，一些抗菌剂对快速生长的偶然分枝杆菌和龟分枝杆菌具有良好的活性，但目前仍没有一种易于应用的临床分离株药敏试验方法。我们评估了用穆勒-欣顿琼脂的纸片扩散法，并对59株偶然分枝杆菌和11株龟分枝杆菌进行了48小时读数，将结果与9种抗菌剂的琼脂稀释药敏结果进行了比较。所有分离株对每毫升16微克的阿米卡星或卡那霉素敏感，最小抑菌圈直径分别为14毫米和18毫米。阿米卡星在2微克/毫升时抑制了100%的偶然分枝杆菌分离株，而11株龟分枝杆菌中有10株（91%）的最小抑菌浓度为4.0微克/毫升或更高。多西环素和米诺环素具有几乎相同的活性，在4.0微克/毫升时抑制了44%的菌株，并且两者都能通过纸片扩散法轻松区分敏感菌株和耐药菌株。尽管大多数龟分枝杆菌分离株在7H10琼脂上生长得更好，但这种培养基的最小抑菌浓度比穆勒-欣顿琼脂高2至8倍。纸片扩散药敏试验似乎是一种简单可靠的方法，可通过琼脂稀释法预测偶然分枝杆菌和大多数龟分枝杆菌分离株的药敏结果。
