Azithromycin-resistant Neisseria gonorrhoeae strains recently isolated in Italy

J Antimicrob Chemother. 2009 Jun;63(6):1200-4. doi: 10.1093/jac/dkp118. Epub 2009 Apr 8.


Objectives: The aim of this study was to characterize 22 azithromycin-resistant Neisseria gonorrhoeae isolates, collected in Italy from January 2007 through June 2008, during a study of the prevalence of antibiotic resistance.

Methods: MICs of azithromycin, ciprofloxacin, ceftriaxone, penicillin and tetracycline were determined by the Etest method. Azithromycin-resistant strains (MIC > or = 1 mg/L) were genetically analysed by N. gonorrhoeae multi-antigen sequence typing (NG-MAST) and PFGE.

Results: A total of 22 azithromycin-resistant isolates were found among the 219 collected. Five of the 22 isolates showed high-level azithromycin resistance (MICs of 128 or 256 mg/L). Sixteen of the 22 were isolated from men who have sex with men. Among the 14 sequence types (STs) found by NG-MAST, 5 STs, containing clusters of two, three or four strains, were homogeneous with respect to epidemiology and/or antibiotic susceptibility. PFGE divided the 22 strains into two main groups that were possibly related.

Conclusions: This is the first report of gonococci with high-level resistance to azithromycin circulating in Italy. Correlation between NG-MAST results and epidemiological data for some of the analysed strains and patients could be established. This study represents a reference point for future surveillance in Italy and suggests the need to add azithromycin to the antibiotic susceptibility panel for gonococci.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Anti-Bacterial Agents / pharmacology*
  • Azithromycin / pharmacology*
  • Bacterial Typing Techniques
  • Cluster Analysis
  • DNA Fingerprinting
  • DNA, Bacterial / genetics
  • Drug Resistance, Bacterial*
  • Female
  • Genotype
  • Gonorrhea / microbiology*
  • Humans
  • Italy
  • Male
  • Microbial Sensitivity Tests
  • Middle Aged
  • Molecular Epidemiology
  • Neisseria gonorrhoeae / classification
  • Neisseria gonorrhoeae / drug effects*
  • Neisseria gonorrhoeae / genetics
  • Neisseria gonorrhoeae / isolation & purification
  • Sequence Analysis, DNA
  • Young Adult


  • Anti-Bacterial Agents
  • DNA, Bacterial
  • Azithromycin