Australian Gonococcal Surveillance Programme Annual Report, 2017

Abstract

The Australian Gonococcal Surveillance Programme (AGSP) has continuously monitored antimicrobial resistance in clinical isolates of Neisseria gonorrhoeae from all states and territories since 1981. In 2017, there were 7,835 clinical isolates of gonococci from public and private sector sources tested for in vitro antimicrobial susceptibility by standardised methods. Current treatment recommendations for gonorrhoea for the majority of Australia, is a dual therapeutic strategy of ceftriaxone and azithromycin. Decreased susceptibility to ceftriaxone (Minimum Inhibitory Concentration or MIC value 0.06-0.125 mg/L) was found nationally in 1.06% of isolates, which is lower than that reported in the AGSP Annual Report 2016 (1.7%). The highest proportions were reported from Victoria and Western Australia (urban and rural) (2.1% and 1.4% respectively). Resistance to azithromycin (MIC value ≥1.0 mg/L) was found nationally in 9.3% of isolates, which is approximately double the proportion reported in 2016 (5.0%) and more than three times the proportion reported in 2015 (2.6%). The highest proportions were reported from Victoria (13.5%), South Australia (12.8%) and New South Wales (9.3%). High level resistance to azithromycin (MIC value ≥256 mg/L) was reported in 4 strains nationally in 2017, 2 from Victoria, one from New South Wales, and one from Queensland.

The proportion of strains resistant to penicillin in non-remote Australia ranged from 10.3% in non-remote Northern Territory to 44.1% in Tasmania. In remote Northern Territory, penicillin resistance rates remain low (2.5%). In remote Western Australia, penicillin resistance rates continue to increase (6.7%) compared to the previous years, however, there were relatively low numbers of strains available for isolate based testing (n=12). To address this and to monitor resistance and inform treatment guidelines, widespread molecular testing for penicillin resistance in Western Australia is in place, and these data are included in the AGSP.

The proportion of strains resistant to ciprofloxacin in non-remote Australia ranged from 17.2% in non-remote Northern Territory to 61% in Tasmania. Ciprofloxacin resistance rates remain comparatively low in remote Northern Territory (1.3%) and remote Western Australia (5.0%).