Spontaneous Erythromycin Resistance Mutation in a 23S rRNA Gene, rrlA, of the Extreme Thermophile Thermus thermophilus IB-21

Spontaneous, erythromycin-resistant mutants of Thermus thermophilus IB-21 were isolated and found to carry the mutation A2058G in one of two 23S rRNA operons. The heterozygosity of these mutants indicates that A2058G confers a dominant or codominant phenotype in this organism. This mutation provides a valuable tool for the genetic manipulation of the 23S rRNA genes of Thermus.