Acquired macrolide resistance genes and the 1 bp deletion in the mtrR promoter in Neisseria gonorrhoeae

• Published in: Journal of antimicrobial chemotherapy 2003-01, Vol.51 (1), p.131-133
• Main Authors: Cousin Jr, Sydney L., Whittington, William L. H., Roberts, Marilyn C.
• Format: Article
• Language: English
• Subjects: acquired resistance; Anti-Bacterial Agents - pharmacology; Antibacterial agents; Antibiotics. Antiinfectious agents. Antiparasitic agents; Bacterial Proteins - genetics; Bacteriology; Base Pairing - genetics; Biological and medical sciences; Drug Resistance, Bacterial - genetics; Ferredoxin-NADP Reductase; Fundamental and applied biological sciences. Psychology; Genetics; macrolide resistance; Macrolides; Medical sciences; Microbial Sensitivity Tests - statistics & numerical data; Microbiology; N. gonorrhoeae; Neisseria gonorrhoeae - drug effects; Neisseria gonorrhoeae - genetics; Neisseria gonorrhoeae - isolation & purification; Pharmacology. Drug treatments; Promoter Regions, Genetic - genetics; Repressor Proteins - genetics; Sequence Deletion - genetics
• ISSN: 0305-7453; 1460-2091; 1460-2091
• DOI: 10.1093/jac/dkg040

The presence of macrolide-lincosamide-streptogramin B resistance genes erm(B), erm(C) and erm(F), the macrolide resistance mef(A) gene, and the DNA sequence of a 13 bp repeat in the promoter region of the mtrR gene, were determined in 62 Neisseria gonorrhoeae isolates collected between 1992 and 1999 in Seattle, Washington, USA. Eleven isolates with erythromycin and azithromycin MICs of ≤0.06 mg/L, had no acquired genes or deletions in the 13 bp repeat region. Among 44 isolates with erythromycin MICs 1.0–16.0 mg/L, and azithromycin MICs 0.06–4.0 mg/L, 16 carried the 1 bp deletion in the mtrR promoter region alone, nine carried one or more of the four acquired macrolide resistance genes alone, and 14 carried both acquired macrolide resistance genes plus the 1 bp deletion in the mtrR promoter region. Three isolates with erythromycin MICs ≥ 8 mg/L, and azithromycin MICs of 4.0 mg/L, carried only erm genes. Five isolates with MICs of 1–2 mg/L did not carry the 1 bp deletion, or any of the acquired resistance genes examined. Our data suggest that the 1 bp deletion in the mtrR promoter region is not found in all erythromycin-resistant (MIC ≥ 1.0 mg/L) N. gonorrhoeae.