Annual report of the Australian Meningococcal Surveillance Programme, 2002

Since 1994, The National Neisseria Network, a nationwide collaborative laboratory program, has examined and analysed isolates of Neisseria meningitidis from cases of invasive meningococcal disease in Australia. The phenotypes (serogroup, serotype and serosubtype) and antibiotic susceptibility of 393 isolates of N. meningitidis from invasive cases of meningococcal disease were determined in 2002. Most disease was caused by serogroup B (210 isolates, 53%) or serogroup C (162 isolates, 41%) meningococci. An increased number of isolates in Victoria (129 from 77 in 2001) accounted for most of the increased national total. A diversity of phenotypes circulated in the different states and territories. Serogroup B strains predominated in all jurisdictions except Victoria, Tasmania and the Australian Capital Territory and were isolated from sporadic cases of invasive disease. Serogroup B phenotypes B:4:P1.4(7) and B:15:P1.7 were the most common and widely distributed. The common serogroup C phenotype in Victoria, C:2a:P1.4(7), was also common in Tasmania. Elsewhere in Australia it was detected only in low numbers. Other C:2a serosubtypes were prominent in other jurisdictions. About two-thirds of all isolates showed decreased susceptibility to the penicillin group of antibiotics (MIC 0.06 to 0.5 mg/L). Two isolates, one each from Darwin and Sydney, had MICs of 1 mg/L. From 1999, reports have also included diagnoses made by non-culture-based methods in these analyses. Data relating to 187 laboratory-confirmed but culture-negative cases supplemented information on culture confirmed cases in this report.