Mechanisms of Microbial Resistance

• Published in: Antisepsis, Disinfection, and Sterilization pp. 253 - 334
• Main Author: McDonnell, Gerald E
• Format: Book Chapter
• Language: English
• Published: United States ASM Press 2007; American Society for Microbiology (ASM)
• Subjects: bacterial resistance; Biochemistry, Biology & Biotechnology; biocide resistance; Biology & Microbiology; Clinical Microbiology; fungal resistance; Industrial Microbiology; mycobacteria; prion resistance; Public health & preventive medicine
• ISBN: 155581901X; 9781555819019; 9781555813925; 1555813925
• DOI: 10.1128/9781555816445.ch8

This chapter discusses the various mechanisms of biocide resistance described in microorganisms. Resistance can be either a natural property of an organism (intrinsic) or acquired by mutation or by the acquisition of plasmids (self‐replicating extrachromosomal DNA) or transposons (chromosomal or plasmid‐integrating transmissible DNA cassettes). The biocide concentration is an important variable and must at least be at the MIC or, preferably, at the minimum biocidal concentration to have a significant effect. Mechanisms of intrinsic resistance are described with further consideration of the various types of bacteria. The first acquired resistance mechanisms reported were against mercury compounds and other metallic salts. In recent years, acquired mechanisms of resistance to other types of biocides have been observed, notably in gram‐positive staphylococci. The proposed mechanisms of prion resistance are summarized. In comparison with bacteria, very little is known about the ways in which fungi can circumvent the actions of biocides and biocidal processes. As with bacteria, two general mechanisms of resistance can be identified: intrinsic resistance, a natural property or development of the organism during normal growth, and acquired resistance, with examples of both identified or proposed.