Resistance of artificial biofilms of Pseudomonas aeruginosa to imipenem and tobramycin
Resistance of artificial biofilms of Pseudomonas aeruginosa to imipenem and tobramycin
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DOI：
10.1093/jac/42.6.755
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发表时间：
1998-12-01
影响因子：
5.2
通讯作者：
Jouenne, T
中科院分区：
文献类型：
--
作者：
Coquet, L;Junter, GA;Jouenne, T
将铜绿假单胞菌的活细胞包埋在藻酸盐凝胶层中，并在最小葡萄糖（15 g/L）-酵母提取物（2 g/L）-盐培养基中孵育以形成人工生物膜样结构。培养2天后，聚合物内的生物量分布是高度不均匀的。细胞数量在凝胶结构的外部区域达到约10（11）个细胞/g凝胶，而内部区域较少定殖（c. 10（8）个细胞g/凝胶）。亚胺培南和妥布霉素对固定化微生物的杀灭作用与游离细胞实验（接种物c。10（9）个细胞/ml）。与悬浮细胞相比，类座状细菌对单独使用或联合使用的两种抗生素表现出更高的抗性。暴露于20 x MIC亚胺培南和15 x MIC妥布霉素10 h，可将活的固定化细菌数量分别减少至初始细胞群的0.3%和3%，而这些抗生素浓度对无细胞培养物更有效（杀菌）（6 h内5 log杀灭）。妥布霉素和亚胺培南的协同作用，检测细菌悬浮液，但不是生物膜样结构。有效的扩散率测量表明，亚胺培南在海藻酸盐层中的扩散不受阻碍。轻微但显着的增强β-内酰胺酶诱导固定化细胞相比，他们的悬浮同行是不够的，以解释高耐药的座状细菌。
Viable cells of Pseudomonas aeruginosa were entrapped in alginate gel layers and incubated in a minimal glucose (15 g/L)-yeast extract (2 g/L)-salt medium to form artificial biofilm-like structures. After cultivation for 2 days, the biomass distribution inside the polymer was highly heterogeneous. The cell number reached approximately 10(11) cells/g gel in the outer regions of the gel structures whereas the inner areas were less colonized (c. 10(8) cells g/gel). Killing of immobilized organisms by imipenem and tobramycin were compared with free-cell experiments (inoculum c. 10(9) cells/ml). Sessile-like bacteria displayed a higher resistance to the two antibiotics used alone or in combination than did suspended cells. Exposure for 10 h to 20 x MIC imipenem and 15 x MIC tobramycin reduced the number of viable immobilized bacteria to 0.3% and 3%, respectively, of the initial cell population, whereas these antibiotic concentrations were much more efficient (bactericidal) against free-cell cultures (5 log kill in 6 h). A synergic effect of tobramycin and imipenem was detected on bacterial suspensions but not on biofilm-like structures. Effective diffusivity measurements showed that the diffusion of imipenem in the alginate layer was not hindered. A slight but significant enhancement of beta-lactamase induction in immobilized cells as compared with their suspended counterparts was insufficient to explain the high resistance of sessile-like bacteria.