Australian Meningococcal Surveillance Programme annual report, 2019

Invasive meningococcal disease (IMD) is a notifiable disease in Australia, and both probable and laboratory-confirmed cases of IMD are reported to the National Notifiable Diseases Surveillance System (NN DSS). In 2019, there were 206 notifications of IMD. Of these, 202 were laboratory-confirmed cases analysed by the reference laboratories of the Australian National Neisseria Network (NNN). Of the 202 laboratory-confirmed cases of IMD, 167 were confirmed by bacterial culture and 35 by nudeic acid amplification testing, and all had the serogroup determined. Fine typing was available on 146 samples (146/202, 72%). Neisseria meningitidis serogroup B (MenB) infections accounted for 50.0% (101/202); MenW for 26.2% (53/202); MenY for 20.8% (42/202) and MenC for 3.0% of cases (6/202). Of the MenW cases, 88% were PorA antigen type P1.5,2, and 65% of these (24/37) were sequence type 11, the hypervirulent strain reported in recent outbreaks in Australia and overseas. The primary peaks of IMD notifications in Australia in 2019 were observed in infants less than 1 year of age (36/202, 18%) and in adults aged 65 years or older (39/202, 19%). MenB infections predominated in those aged less than 5 years and those aged 15-19 years, whereas MenW and MenY infections predominated in those aged 45 years or more. All 167 IMD isolates were tested for antimicrobial susceptibility. One isolate out of these 167 (0.6%) was resistant to penicillin with an MIC >= 1mg/L; 154/167 isolates (92%) had decreased susceptibility to penicillin. All isolates were susceptible to ceftriaxone and ciprofloxacin, and one isolate was resistant to rifampicin.