Prosser B L, Taylor D, Dix B A, Cleeland R
Department of Chemotherapy, Hoffmann-La Roche Inc., Nutley, New Jersey 07110.
Antimicrob Agents Chemother. 1987 Oct;31(10):1502-6. doi: 10.1128/AAC.31.10.1502.
Antibiotics are generally not effective against organisms in exopolysaccharide biofilms. A simple method of studying the effect of antibiotics on bacteria in established biofilms is reported. Escherichia coli ATCC 25922 cells grown overnight at 37 degrees C on Mueller-Hinton agar were suspended in buffer and dispensed on 0.5-cm2 catheter disks. The disks were incubated for 1 h at 37 degrees C, washed, transferred to petri dishes containing 20 ml of broth, and incubated at 37 degrees C for 20 to 22 h, at which time thick biofilms were established. Disks were washed, placed in broth or broth containing antibiotic, and incubated at 37 degrees C for 4 h. The disks were removed, and viable counts were determined. This process was repeated at other selected time intervals (e.g., 8 and 24 h). Viable bacterial counts decreased from 10(3) to 10(4) CFU/cm2 in 24 h with 400 micrograms of amdinocillin or cefamandole per ml. A combination containing 400 micrograms of each antibiotic per ml decreased the viable counts to an undetectable level (less than 100 CFU/cm2) in 24 h. Other antibiotics and organisms were also examined in this system.
抗生素通常对胞外多糖生物膜中的微生物无效。本文报道了一种研究抗生素对已形成生物膜中细菌作用效果的简单方法。将在穆勒 - 欣顿琼脂上于37℃过夜培养的大肠埃希菌ATCC 25922细胞悬浮于缓冲液中，并接种到0.5平方厘米的导管盘上。将这些盘在37℃孵育1小时，洗涤后，转移至含有20毫升肉汤的培养皿中，并在37℃孵育20至22小时，此时形成厚生物膜。将盘洗涤后，置于肉汤或含抗生素的肉汤中，在37℃孵育4小时。取出盘并测定活菌数。在其他选定的时间间隔（如8小时和24小时）重复此过程。每毫升含400微克氨比西林或头孢孟多，活菌数在24小时内从10³至10⁴CFU/平方厘米下降。每毫升含400微克每种抗生素的组合在24小时内将活菌数降至不可检测水平（小于100 CFU/平方厘米）。该系统还检测了其他抗生素和微生物。
