Epidemiological surveillance study of gonococcal infection in Northern Spain

Treatment of gonorrhoea is threatened by antimicrobial resistance, and decreased susceptibility to recommended therapies is emerging. Thus, gonococcal infection (GI) is becoming a public health problem. The objectives of the present study were to monitor the antimicrobial sensitivity in Neisseria gonorrhoeae (NG) during 2011-2015 and to study their genogroups.

Antimicrobial susceptibility was studied by disc diffusion, in addition to the agar dilution method for cefixime and ceftriaxone and the Etest® for azithromycin. Genotyping was performed by the NG multi-antigen sequence typing (NG-MAST) method. Genogroups of closely related sequence types (STs) were defined.

All the strains were susceptible to cefixime, ceftriaxone and gentamicin and 1.8% of the strains were resistant to azithromycin. A total of 531 STs and 6 genotypes (Gs) were identified during 2012-2015 period. G2992 was the largest and was associated with resistance to azithromycin, and with men who have sex with men (MSM), alongside G2400. G1407 and G2400 strains were related to high minimum inhibitory concentration (MICs) to cefixime and G1407 also to ceftriaxone. For the first time, G1861 and G2018 were described and associated with ciprofloxacin resistance and G2018 also with high MICs to ceftriaxone.

Molecular typing is a useful tool to predict antimicrobial resistance. These results show the need to develop novel antimicrobials or to design new antimicrobial therapies based on drugs that show their efficacy against GI. This also highlights the importance of developing sexually transmitted infection (STI) surveillance in homosexual populations.