Annual report of the Australian Meningococcal Surveillance Programme, 2008

In 2008, there were 260 laboratory-confirmed cases of invasive meningococcal disease (IMD) analysed by the National Neisseria Network, a nationwide network of reference laboratories. One hundred and forty-nine isolates of Neisseria meningitidis from invasive cases of meningococcal disease were available for which the phenotypes (serogroup, serotype and serosubtype) and antibiotic susceptibility were determined. An additional 111 cases were confirmed by non-culture based methods. Nationally, 223 (85%) laboratory-confirmed cases where a serogroup was determined were infected with serogroup B and 17 (6.5%) infected with serogroup C meningococci. Nationally, the total number of confirmed cases has remained relatively stable since 2006, but the number of cases in each jurisdiction may vary from year to year. Queensland had the highest number of recorded cases in 2008. Typical primary and secondary disease peaks were observed in those aged 4 years or less and in adolescents and young adults respectively. Serogroup B cases predominated in all age groups and jurisdictions. The common phenotypes circulating in Australia were again B:15:P1.7 and B:4:P1.4. Although serogroup C cases were numerically low, phenotype C:2a:P1.5 predominated in this group. No evidence of meningococcal capsular 'switching' was detected. About three-quarters of all isolates showed decreased susceptibility to the penicillin group of antibiotics (MIC 0.06-0.5 mg/L). All isolates remained susceptible to ceftriaxone. One isolate had reduced susceptibility to rifampicin and two to ciprofloxacin.