Erythromycin-Resistant Neisseria gonorrhoeae and Oral Commensal Neisseria spp. Carry Known rRNA Methylase Genes

Abstract

ABSTRACT Two Neisseria gonorrhoeae isolates from Seattle and two isolates from Uruguay were resistant to erythromycin (MIC, 4 to 16 μg/ml) and had reduced susceptibility to azithromycin (MIC, 1 to 4 μg/ml) due to the presence of the self-mobile rRNA methylase gene(s) ermF or ermB and ermF . The two Seattle isolates and one isolate from Uruguay were multiresistant, carrying either the 25.2-MDa tetM -containing plasmid (Seattle) or a β-lactamase plasmid (Uruguay). Sixteen commensal Neisseria isolates (10 Neisseria perflava - N. sicca , 2 N. flava , and 4 N. mucosa ) for which erythromycin MICs were 4 to 16 μg/ml were shown to carry one or more known rRNA methylase genes, including ermB , ermC , and/or ermF . Many of these isolates also were multiresistant and carried the tetM gene. This is the first time that a complete transposon or a complete conjugative transposon carrying an antibiotic resistance gene has been described for the genus Neisseria .