Mutations in rpoB sequences of Actinobacteria: a confounding factor in conjugal transfer experiments

Antimicrobial resistance is a growing threat to the effective treatment of an increasing range of infections, with severe impacts on human health as well as costs for the healthcare sector. Rifamycins are an important class of antibiotics that are particularly active against Gram-positive micro-organisms and are used in the treatment of tuberculosis and other serious infectious diseases. One of the most important rifamycin derivatives is rifampicin (rifampin). It was introduced in 1968 and since then the rise of resistant spontaneous mutants has been reported, with the most common mechanism being mutation in the nucleotide sequence of rpoB, the gene encoding the β-subunit of RNA polymerase.