Yu Ling-ling, Hu Bi-jie, Huang Sheng-lei, Zhou Zhao-yan, Tao Li-li
Department of Respiratory, Zhongshan Hospital Affiliated of Fudan University, Shanghai 200032, China.
Zhonghua Jie He He Hu Xi Za Zhi. 2011 Jun;34(6):409-12.
To evaluate the activity of macrolides and fluoroquinolones against Legionella pneumophila by intracellular susceptibility testing.
Minimum inhibitory concentration (MIC) was determined by standard agar dilution test according to the CLSI. For intracellular assays, legionella pneumonia was used to infect human monocytic cell line THP-1. Erythromycin, azithromycin, levofloxacin and moxifloxacin at 1 × MIC, 4 × MIC, 8 × MIC were added following phagocytosis. Number of viable bacteria was enumerated at 24 h on BCYE (buffered charcoal yeast extract) agar in duplicates using standard plate count method. The result was expressed as percentage inhibition. Mann-Whitney U test was used to determine the significant differences in mean percentage inhibition between agents.
Percentage inhibition at 24 h were as follows: Erythromycin 1 × MIC (50.18 ± 27.29)%, 4 × MIC (79.48 ± 20.08)%, 8 × MIC (91.46 ± 8.70)%; Azithromycin 1 × MIC (66.77 ± 26.18)%, 4 × MIC (91.73 ± 8.72)%, 8 × MIC (97.10 ± 3.37)%; Levofloxacin 1 × MIC (99.84 ± 0.25)%, 4 × MIC (99.99 ± 0.02)%, 8 × MIC (99.99 ± 0.01)%; Moxifloxacin 1 × MIC (99.90 ± 0.10)%, 4 × MIC (99.99 ± 0.03)%, 8 × MIC (99.99 ± 0.03)%. The fluoroquinolones showed greater inhibitory activity than macrolides against legionella pneumophila(u = 1.0, 2.0, 5.0, P < 0.05). Levofloxacin and moxifloxacin had the same intracellular activity against legionella pneumophila (u = 190, 183, 217, P > 0.05). Azithromycin was more effective than erythromycin in inhibiting intracellular legionella pneumophila (u = 132, 125, 128, P < 0.05).
The fluoroquinolones were more active than macrolides against legionella pneumophila. The intracellular activity of levofloxacin against legionella pneumophila appeared to be similar to moxifloxacin. Azithromycin was demonstrated to have superior activity against legionella pneumophila compared with erythromycin.
通过细胞内药敏试验评估大环内酯类和氟喹诺酮类药物对嗜肺军团菌的活性。
根据美国临床和实验室标准协会（CLSI）的标准琼脂稀释试验测定最低抑菌浓度（MIC）。对于细胞内试验，用嗜肺军团菌感染人单核细胞系THP-1。吞噬作用后加入1×MIC、4×MIC、8×MIC的红霉素、阿奇霉素、左氧氟沙星和莫西沙星。使用标准平板计数法在缓冲活性炭酵母提取物（BCYE）琼脂上一式两份计数24小时时的活菌数。结果以抑制百分比表示。采用曼-惠特尼U检验确定各药物之间平均抑制百分比的显著差异。
24小时时的抑制百分比如下：红霉素1×MIC（50.18±27.29）%，4×MIC（79.48±20.08）%，8×MIC（91.46±8.70）%；阿奇霉素1×MIC（66.77±26.18）%，4×MIC（91.73±8.72）%，8×MIC（97.10±3.37）%；左氧氟沙星1×MIC（99.84±0.25）%，4×MIC（99.99±0.02）%，8×MIC（99.99±0.01）%；莫西沙星1×MIC（99.90±0.10）%，4×MIC（99.99±0.03）%，8×MIC（99.99±0.03）%。氟喹诺酮类药物对嗜肺军团菌的抑制活性高于大环内酯类（u = 1.0、2.0、5.0，P < 0.05）。左氧氟沙星和莫西沙星对嗜肺军团菌的细胞内活性相同（u = 190、183、217，P > 0.05）。阿奇霉素在抑制细胞内嗜肺军团菌方面比红霉素更有效（u = 132、125、128，P < 0.05）。
氟喹诺酮类药物对嗜肺军团菌的活性高于大环内酯类。左氧氟沙星对嗜肺军团菌的细胞内活性似乎与莫西沙星相似。与红霉素相比，阿奇霉素对嗜肺军团菌具有更强的活性。
