Australian Meningococcal Surveillance Programme annual report, 2013.

In 2013, there were 143 laboratory-confirmed cases of invasive meningococcal disease (IMD) analysed by the Australian National Neisseria Network (NNN). This was the lowest number of laboratory confirmed IMD cases referred to the NNN since the inception of the Australian Meningococcal Surveillance Programme in 1994. Probable and laboratory confirmed IMD is notifiable in Australia. There were 149 IMD cases notified to the National Notifiable Diseases Surveillance System in 2013. Meningococcal serogrouping was determined for 139/143 laboratory confirmed IMD cases; 74.8% (104 cases) were serogroup B infections; 5.8% (8 cases) were serogroup C infections; 8.6% (12 cases) were serogroup W135; and 10.8% (15 cases) were serogroup Y. Primary and secondary disease peaks were observed, respectively, in those aged 4 years or less, and in adolescents (15-19 years). Serogroup B cases predominated in all jurisdictions and age groups, except for those aged 65 years or over where serogroup Y predominated. The overall proportion and number of IMD caused by serogroup B decreased from previous years. The number of cases of IMD caused by serogroup C was low, and has been proportionally stable over recent years. The number of IMD cases caused by W135 and Y serogroups was similar to previous years but the proportion has increased with the overall reduction in numbers of IMD cases. Molecular typing was performed on 92 of the 93 IMD isolates, and 23 of the 50 cases confirmed by nucleic acid amplification testing. In 2013, the most common porA genotype circulating in Australia was P1.7-2,4. All IMD isolates tested were susceptible to ceftriaxone; ciprofloxacin and rifampicin. Decreased susceptibility to penicillin was observed in 78.5% of isolates.