Functional assessment of linezolid-responsive sRNA genes in Staphylococcus aureus

Staphylococcus aureus contains a repertoire of at least 50 and possibly 500 small RNAs (sRNAs). The functions of most sRNAs are not understood, although some are known to respond to environmental changes, including the presence of antibiotics. Here, in an effort to better understand the role of sRNAs in the context of antibiotic exposure, we took a clinical methicillin resistant S. aureus (MRSA) isolate and separately deleted sRNAs that were either significantly up-regulated in response to the last-line antibiotic linezolid, highly expressed or previously found to respond to antibiotic exposure. There were no significant changes for any of the 18 mutants in a variety of phenotypic screens, including growth competition assays in the presence of linezolid, biofilm formation and resistance to whole blood killing.