Azithromycin-resistant Neisseria gonorrhoeae strains recently isolated in Italy.
OBJECTIVE
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.
Starnino
S
S
Department of Infectious, Parasitic and Immune-Mediated Diseases, Istituto Superiore di Sanità, Rome, Italy.
Stefanelli
P
P
D000328:Adult; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D017963:Azithromycin / Q000494:pharmacology*; D015373:Bacterial Typing Techniques; D016000:Cluster Analysis; D016172:DNA Fingerprinting; D004269:DNA, Bacterial / Q000235:genetics; D024881:Drug Resistance, Bacterial; D005260:Female; D005838:Genotype; D006069:Gonorrhea / Q000382:microbiology*; D006801:Humans; D007558:Italy; D008297:Male; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D017720:Molecular Epidemiology; D009344:Neisseria gonorrhoeae / Q000145:classification / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification; D017422:Sequence Analysis, DNA; D055815:Young Adult
D000900:Anti-Bacterial Agents; D004269:DNA, Bacterial; D017963:Azithromycin