Abstract
Bacterial antibiotic resistance is often associated with a fitness cost in the absence of the antibiotic [1] and [2]. We have examined a resistance mechanism in Staphylococcus aureus that negates these costs. Exposure to gentamicin both in vitro and in vivo has been reported to result in the emergence of a gentamicin-resistant small colony variant (SCV) [3], [4], [5], [6], [7] and [8]. We show that the emergence of SCVs following exposure to gentamicin results from a rapid switch and that bacteria exposed to cycles of gentamicin followed by antibiotic-free medium repeatedly switched between a resistant SCV and a sensitive parental phenotype (revertants). The fitness of revertants relative to S. aureus with stable gentamicin resistance was greater in drug-free media, which suggests that S. aureus has evolved an inducible and reversible resistance mechanism that circumvents a permanent cost to fitness.
Original language | English |
---|---|
Pages (from-to) | 1810-1814 |
Number of pages | 5 |
Journal | Current Biology |
Volume | 11 |
Issue number | 22 |
DOIs | |
Publication status | Published - 13 Nov 2001 |