Antibiotic-Independent Adaptive Effects of Antibiotic Resistance Mutations. Issue 8 (August 2017)

• Record Type: Journal Article
• Authors: Hershberg, Ruth
• Is Part Of: Trends in genetics. Volume 33:Issue 8(2017)
• Page Start: 521
• Page End: 528
• Publication Date: 2017-08
• Subjects: antibiotic resistance -- evolution -- fitness effects -- adaptation; Genetics -- Periodicals; 576.5
• DOI: 10.1016/j.tig.2017.05.003
• Languages: English
• ISSNs: 0168-9525

Abstract

Abstract : Antibiotic usage selects for the accumulation and spread of antibiotic-resistant bacteria. However, resistance can also accumulate in the absence of antibiotic exposure. Antibiotics are often designed to target widely distributed regulatory housekeeping genes. The targeting of such genes enables these antibiotics to be useful against a wider variety of pathogens. This review highlights work suggesting that regulatory housekeeping genes of the type targeted by many antibiotics function as hubs of adaptation to conditions unrelated to antibiotic exposure. As a result of this, some mutations to the regulatory housekeeping gene targets of antibiotics confer both antibiotic resistance and an adaptive effect unrelated to antibiotic exposure. Such antibiotic-independent adaptive effects of resistance mutations may substantially affect the dynamics of antibiotic resistance accumulation and spread. Trends: Antibiotic resistance mutations often occur within the regulatory housekeeping gene targets of antibiotics. Such resistance mutations can carry pronounced antibiotic-independent fitness effects on the bacteria carrying them. Antibiotic resistance mutations, occurring within regulatory housekeeping genes often reduce fitness, when bacteria are not exposed to antibiotics. However, such resistance mutations may also carry adaptive effects that are independent of antibiotic exposure. The regulatory housekeeping gene targets of many antibiotics have been shown to serve as hubs of adaptation to non-antibiotic-related conditions. Adaptive mutations occurring within the regulatory housekeeping genes targets of antibiotics are often antagonistically pleiotropic (i.e., adaptive under some conditions, while deleterious under others). Some antibiotic resistance mutations within regulatory housekeeping genes segregate at alarming frequencies within natural environments, in a manner that appears to be independent of direct antibiotic exposure.