Australian Meningococcal Surveillance Programme Annual Report, 2021

Area of Science:

• Epidemiology
• Microbiology
• Public Health

Background:

• Invasive meningococcal disease (IMD) is a significant public health concern in Australia, requiring continuous surveillance.
• Mandatory reporting of probable and confirmed IMD cases to the National Notifiable Diseases Surveillance System (NNDSS) ensures data accuracy.

Purpose of the Study:

• To analyze the epidemiology and characteristics of IMD cases reported in Australia in 2021.
• To identify dominant serogroups, age distributions, and antimicrobial susceptibility patterns of IMD pathogens.

Main Methods:

• Retrospective analysis of IMD notifications to the NNDSS in 2021.
• Laboratory confirmation using bacterial culture and nucleic acid amplification testing.
• Serogroup determination, fine typing (porA, MLST), and antimicrobial susceptibility testing (MIC values).

Main Results:

• A total of 74 IMD notifications were recorded, the lowest since 1991. Serogroup B (MenB) was predominant (52%), followed by MenW (22%) and MenY (19%).
• Age peaks were observed in children under 5 and adolescents aged 15-19. MenB predominated in adolescents, MenW in infants, and MenY in older adults.
• Penicillin resistance or intermediate susceptibility was noted in 72% of isolates. All isolates remained susceptible to ceftriaxone and rifampicin, with one MenB isolate showing ciprofloxacin resistance.

Conclusions:

• The low IMD incidence in 2021 highlights the impact of public health interventions, but ongoing surveillance is crucial.
• Distinct serogroup-age associations necessitate targeted prevention and treatment strategies.
• Emerging antimicrobial resistance, particularly to penicillin, warrants close monitoring and consideration in treatment guidelines.