Spontaneous and on point: Do spontaneous mutations used for laboratory experiments cause pleiotropic effects that might confound bacterial infection and evolution assays?

Abstract

Many selectable phenotypes in microbial systems, including antibiotic resistance, can be conferred by single point mutations. This is frequently exploited in research, where the selection and use of microbial mutants that are spontaneously resistant to antibiotics like rifampicin and streptomycin facilitate the recovery and/or quantification of a target microbe. Such mutations are commonly employed as genetic markers for in vitro and in vivo experiments, often with little consideration as to the ultimate system-level impact of these single nucleotide mutations on the physiology of the microbe. There is substantial literature on the pleiotropic effects of point mutations conferring antibiotic resistance; yet, it is unclear whether this work is considered by the research communities outside of the discipline. This review examines some of the known pleiotropic effects of point mutations that provide selectable resistance markers, and how these mutations may impact general physiology and growth in host and non-host environments.

Keywords: antibiotic resistance; pleiotropic effects; point mutation; rifampicin; spontaneous; streptomycin.