近十年來由於多重抗藥性細菌，例如multidrug-resistant，extensively drug-resistant 甚至對目前後線抗生素完全無效的pandrug-resistant 菌種迅速竄起，此種新興抗藥性細菌已經成為各醫療院所治療病人時面臨之難題。而新抗生素的研發已經趕不上臨床之需求，臨床醫師在治療相關重症病人時，若所面對是這些多重抗藥性細菌，將面臨無藥可用的窘境。這使得醫界及藥界被迫回頭積極找尋老抗生素再予以重新應用的可能性，例如polymyxins(colistin)、fosfomycin、isepamicin、fusidic acid、chloramphenicol、trimethroprim/sulfamethoxazole 等。於是， 不管是在個別藥物動力學(pharmacokinetic) 或藥效學(pharmacodynamic)上，這些老藥被重啟研究之大門，以期能在治療多重抗藥性細菌引起之感染時能有所助益；另一方面也對老藥加上新藥的合併療法(combination therapy)多所著墨。其中又以colistin 與fosfomycin 被證實能有效的應用於臨床最為熱門。然而，這些老藥未來仍需進一步的研究以釐清它們在臨床應用的真正價值。

The emergence of multidrug-resistant(MDR), extensively drug-resistant(XDR), and even pandrug-resistant (PDR) bacteria has become a challenge in hospitals in recent decades. The lack of new antibiotics to treat these pathogens leads to the revival of old antibiotics, including polymyxins(colistin),fosfomycin, isepamicin, fusidic acid,chloramphenicol and trimethroprim/sulfamethoxazole, with the hope in treating patients successfully. With the better understanding of the phamacokinetics and pharmacodynamics of these old antibiotics, there are many clinical reports on the successful use of these drugs in combination with
new antibiotics against those difficult-to-treat infections. Among them, colistin and fosfomycin have been considered as the vivid paradigm. However, the real clinical benefit of using old antibiotics-containing therapies for the treatment of MDR bacteria in terms of clinical outcome and survival rates still needs to be elucidated in the future.