New Mutation in 23S rRNA Gene Associated with High Level of Azithromycin Resistance in Neisseria gonorrhoeae

Abstract

Although azithromycin (1 g orally in a single dose) is not recommended for treating gonorrhea, it is still used in some parts of the world, and it is widely used either to treat Chlamydia trachomatis infections or, in combination withexpanded-spectrum cephalosporins, to treat simultaneous infections with both chlamydia and gonococci (7). A higher dose of 2 g of new formulations of azithromycin with a lower incidence of gastrointestinal intolerance may be more effective (9), but recent descriptions of gonococcal strains showing azithromycin resistance or high-level azithromycin resistance (AzHLR; MIC of azithromycin, 256 mg/liter) would make that treatment untenable if strains of this type were to emerge elsewhere and spread (1, 2, 6).