Background Neisseria gonorrhoeae (NG) has an extraordinary ability to develop resistance to all antimicrobials used for its treatment. This study analysed molecular determinants of antimicrobial resistance and NG-MAST of 153 NG isolates collected at Florianopolis metropolitan area during 2008–2016.

Methods Minimal Inhibitory Concentration (MIC) was determined by agar dilution and the molecular epidemiology was evaluated by NG-MAST.

Results Resistance was observed to penicillin (PEN) (26.1%), tetracycline (TET) (41.2%), ciprofloxacin (CIP) (52.3%) and azithromycin (AZT) (5.2%). All isolates were susceptible to cefixime (CFX) and ceftriaxone (CRO). However, 8.5% of isolates had MIC=0.125 mg/L for CFX, one log below the resistance cut-off point (EUCAST). β-lactamase production was detected in 12.4% of isolates and one of them carried the bla _TEM-135 allele. The American or Dutch tetM gene were carried by 5.2% of the isolates. Mutations in the QRDR were observed in 87.5% of isolates resistant to CIP. NG-MAST showed 64 different sequence types (STs), including 19 novel STs. ST225, ST2992, ST1582, ST338, ST1407, ST2202 and ST6827 were most prevalent. G225 genogroup was associated with resistance to CIP (p<0.001), PEN (p=0.016) and TET (p<0.001) whereas G1407 genogroup was associated with MIC=0.125 mg/L for CFX (p=0.001), resistance to CIP, PEN (p=0.016) and TET (p<0.001). Isolates that shared the same tbpB 29 allele were associated with resistance to AZT (p=0.008) and PEN (p=0.035). ST338 was associated with bla _TEM-1 gene (p<0.001) and tetM (p=0.006), whereas the cluster sharing the same tbpB 137 allele was associated with tetM gene.

Conclusion This study showed high rates of resistance to PEN, TET and CIP associated with persistence and dissemination of gonococcal strains resistant to CIP and plasmid resistance to PEN and TET. Despite the high resistance profile to CIP, the treatment recommended to the south region of Brazil was the association of CIP-AZT until 2017, when the national recommendation changed it to CRO-AZT.

Disclosure No significant relationships.