Free Trial

Safari Books Online is a digital library providing on-demand subscription access to thousands of learning resources.


  • Create BookmarkCreate Bookmark
  • Create Note or TagCreate Note or Tag
  • PrintPrint
Share this Page URL
Help

Chapter 3. A Survey of Antibiotics > Most Antifungal Agents Attack Membranes an...

Most Antifungal Agents Attack Membranes and Cell Walls

All cells are surrounded by a semi-permeable membrane that contains a variety of proteins, lipids (fats), and sterols. Cholesterol is one of the sterol components of mammalian cell membranes. Fungal cells are biochemically similar to human cells, but their membranes contain ergosterol rather than cholesterol. The enzymes responsible for making ergosterol differ from those involved in making cholesterol; consequently, drugs that interfere with ergosterol formation are specific to fungal cells.

The yeast Candida albicans (see Figure 3-1) is a normal inhabitant of the mouth, throat, and vagina; it is kept under control by host defenses. However, C. albicans causes life-threatening systemic infections in persons undergoing cancer chemotherapy or otherwise experiencing immune suppression (see Box 3-3). Among the effective antifungals are triazoles, such as fluconazole, that target ergosterol. Triazoles weaken the membrane surrounding fungal cells and prevent fungal growth. Another effective drug is the polyene called amphotericin B. It binds to ergosterol and creates holes in fungal cell walls. Those holes then kill the fungus. Although amphotericin B is more active than triazoles, it has serious side effects that include kidney damage. Amphotericin B is generally not the first choice for fungal treatment.


  

You are currently reading a PREVIEW of this book.

                                                                                                                    

Get instant access to over $1 million worth of books and videos.

  

Start a Free Trial


  
  • Safari Books Online
  • Create BookmarkCreate Bookmark
  • Create Note or TagCreate Note or Tag
  • PrintPrint