Trend of ciprofloxacin resistance in Neisseria gonorrhoeae strains isolated in Italy and analysis of the molecular determinants.

A total of 599 Neisseria gonorrhoeae strains collected in Italy in 2 periods, 2003 to 2005 and 2007 to 2008, were screened for ciprofloxacin susceptibility by Etest. Ciprofloxacin-resistant strains (49.7%) were characterized by i) serovar determination, patterns of mutation in gyrA, and parC genes (38%, randomly selected) and ii) N. gonorrhoeae multiantigen sequence typing (56% of the strains isolated from patients who declared their sexual orientation). The percentage of ciprofloxacin-resistant strains increased from 42 (2003-2005) to 58 (2007-2008); in the second period, strains with MIC value >32 microg/mL have been observed. Mutations in gyrA and parC genes were identified in the majority of strains (88%). Ciprofloxacin-resistant isolates among men who have sex with men (MSM) increased from 24% in 2003 to 2005 to 47% in 2007 to 2008. However, sequence types exclusively found among MSM were mostly due to a single strain. This is the first study in Italy combining N. gonorrhoeae ciprofloxacin susceptibility testing with molecular analyses and comparing the results over time.