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Annual report of the Australian Meningococcal Surveillance Programme, 1997
Abstract:
The National Neisseria Network (NNN) has undertaken meningococcal isolate surveillance by means of a collaborative laboratory based initiative since 1994. The phenotype (serogroup, serotype and serosubtype) and antibiotic susceptibility of 343 isolates of Neisseria meningitidis from invasive cases of meningococcal disease were determined in 1997. Ninety six percent of the invasive isolates were serogroup B or C. Serogroup B strains predominated in all States and Territories and were isolated from sporadic cases of invasive disease. Phenotypes B:4:P1.4 and B:15:P1.7 were prominent. Serogroup C isolates were most often encountered in New South Wales, especially in adolescents and young adults, and in that State were nearly as numerous as serogroup B strains. C:2a:P1.5 was the most frequently encountered phenotype and C:2b:P1.2 strains were also distributed widely. A number of clusters of cases of serogroup C disease were noted, mainly with phenotype C:2a:P1.5. About three quarters of all isolates showed decreased susceptibility to the penicillin group of antibiotics (MIC 0.06 to 0.5 mg/L). Three isolates showed reduced susceptibility to rifampicin and one was chloramphenicol resistant.
Insights
The National Neisseria Network (NNN) monitored invasive meningococcal disease isolates in 1997. Serogroup B and C strains dominated, with varying phenotypes and decreased susceptibility to penicillin observed in most isolates.
Area of Science:
- Microbiology
- Epidemiology
- Public Health
Background:
- The National Neisseria Network (NNN) has conducted collaborative laboratory-based surveillance of meningococcal isolates since 1994.
- Meningococcal disease remains a significant public health concern, necessitating ongoing monitoring of circulating strains and their characteristics.
Purpose of the Study:
- To determine the phenotype and antibiotic susceptibility of Neisseria meningitidis isolates from invasive cases in 1997.
- To identify prevalent serogroups, serotypes, and serosubtypes of meningococcal disease in Australia.
Main Methods:
- Analysis of 343 Neisseria meningitidis isolates from invasive cases in 1997.
- Determination of isolate phenotypes (serogroup, serotype, serosubtype) and antibiotic susceptibility profiles.
Main Results:
- Ninety-six percent of invasive isolates were serogroup B or C.
- Serogroup B strains predominated nationally, associated with sporadic cases. Prominent phenotypes included B:4:P1.4 and B:15:P1.7.
- Serogroup C isolates were frequent in New South Wales, particularly among adolescents and young adults. The C:2a:P1.5 phenotype was most common, with clusters noted.
- Approximately 75% of isolates exhibited decreased susceptibility to penicillin antibiotics.
- Reduced susceptibility to rifampicin was observed in three isolates, and one isolate was resistant to chloramphenicol.
Conclusions:
- Serogroup B and C strains were the primary causes of invasive meningococcal disease in 1997.
- Specific phenotypes were associated with particular serogroups and geographical locations.
- Emerging antibiotic resistance, particularly decreased penicillin susceptibility, highlights the need for continued surveillance.