Annual report of the Australian Meningococcal Surveillance Programme, 2007--Amended.

In 2007 there were 281 laboratory-confirmed cases of invasive meningococcal disease analysed by the National Neisseria Network, a nationwide network of reference laboratories. The phenotypes (serogroup, serotype and serosubtype) and antibiotic susceptibility of 154 isolates of Neisseria meningitidis from invasive cases of meningococcal disease were determined and an additional 127 cases were confirmed by non-culture based methods. Nationally, 223 (85%) confirmed cases where a serogroup was determined were infected with serogroup B and 17 (6.5%) with serogroup C meningococci. The total number of confirmed cases was 10 more than the 271 cases identified in 2006. Queensland and New South Wales recorded slight increases in case numbers and Victoria recorded a decline. 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 B:15:P1.7, B:4:P1.4 and C:2a:P1.5. 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 rifampicin. A single serogroup B isolate had decreased susceptibility to ciprofloxacin (MIC 0.06 mg/L). This was the first local isolate of this type since the original report of this phenomenon in Australia in 2000.