Australian Meningococcal Surveillance Programme annual report, 2010

Abstract

In 2010 there were 214 laboratory-confirmed cases of invasive meningococcal disease analysed by the National Neisseria Network, a nationwide network of reference laboratories. One hundred and twenty-four isolates of Neisseria meningitidis from invasive cases of meningococcal disease were available for which the phenotypes (serogroup, serotype and serosubtype) and/or genotype and antibiotic susceptibility were determined. An additional 90 cases were confirmed by non-culture based methods (77 by nucleic acid amplification testing and 13 by serology), and where possible, serotyping was determined. Nationally 167 (78%) laboratory-confirmed cases, where a serogroup was determined, were infected with serogroup B, 16 (7.5%) with serogroup C, 9 (4.2%) with serogroup W135 and 7 (3.3%) with serogroup Y meningococci. The national total of confirmed cases has decreased since 2004, but the number of cases may vary between jurisdictions each year. New South Wales had the highest number of recorded cases in 2010. 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 phenotype circulating in Australia continues to be B:15:P1.7, corresponding to the porA genotype P1.7,16-26. Serogroup C cases were again numerically low, as were serogroups W135 and Y. Eighty per cent of all isolates showed decreased susceptibility to the penicillin group of antibiotics (minimal inhibitory concentration (MIC) 0.06-0.5 mg/L). All isolates remained susceptible to ceftriaxone. One isolate had reduced susceptibility to ciprofloxacin, and none to rifampicin.