摘要或動機

The purpose of this study is to set up a quick, easy and economical way to evaluate the ability of different concentration of various antibiotics to penetrate biofilm and establish the antimicrobial susceptibility patterns of various antibiotics. The susceptibility of five antibiotics upon sessile cultures of Bacillus subtlis ATCC 6633, Escherichia coli XL, Pseudomonas aeruginosa ATCC 27853, Staphylococcus aureus ATCC 29213 and Sarcina lutea ATCC 9341 were measured ATCC 27853, and S. aureus ATCC 29213 proved to be very difficult to eradicate, with only Gentamicin proving to effective at achievable drug concentrations, but the S. lutea ATCC 9341 biofilm was the most susceptible to the Penicillin. The results demonstrated that for biofilms of the same organisms, several hundred to thousand times the concentration of a certain antibiotic were often required for the antibiotic to be effect, while other antibiotics were found to be effective at the MICs. The concentration of antibiotic to penetrate the biofilm is proportional to the thickness of biofilm. Indeed, our research have already indicated that the use of MIC values to indicate antibiotics effectiveness is misleading, because MIC values can not represent the actual effect of anticbiotics on microbiologicals that have developed biofilm. The antimicrobial susceptibility patterns of antibiotics to various bacterial biofilm are different. The susceptibility of the mixed biofilm depends on the physical and biological change of biofilm. Our biofilm device offers a new technology for the rational evaluation of antibiotics effective against microbial biofilms and for the screening of new effective antibiotic drugs.此研究之目的是要建立一套操作簡便、快速且費用低廉之生物膜厚度產生方法，藉此探討不同生物膜厚度對抗生素抗菌之影響，進而完成抗生素對生物模之抗菌圖譜。本實驗將測試五種抗生素Bacillus subtilis ATCC6633，Escherichia coli XL，Pseudomonas aeruginosa ATCC27853，Staphylococcus aureus ATCC29213和Sarcina lutea ATCC9341之抗菌圖譜。試驗結果顯示Gentamicin對前四株試菌有較佳之穿透力，對S.lutea ATCC 9341則是Penicillin。實驗結果證明最小抑制濃度值確實無法實際有效地表達對已形成生物膜菌體之抗菌效果，要完全去除生物膜之抗生素濃度是為最小抑制濃度之數百倍到數千倍，而且抗生素用藥濃度隨著生物膜厚度增加而成比例增加。不同抗生素對不同菌株生物膜有不同之抗菌圖譜，混合菌株生物膜是否會促進或抑制抗生素之穿透力，端視其生物膜結構有無改變。本實驗方法可以做為一種快速檢定抗生素對細菌生物膜敏感性之新技術，同時亦可有效地篩選新的抗生素藥物對生物膜的抗菌效應。