Australian Meningococcal Surveillance Programme annual report, 2018.

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 IMD cases to the National Notifiable Diseases Surveillance System (NNDSS) ensures comprehensive data collection.

Purpose of the Study:

• To analyze the epidemiology and characteristics of IMD cases reported in Australia in 2018.
• To identify prevalent serogroups, age distributions, and antimicrobial susceptibility patterns of IMD isolates.

Main Methods:

• Analysis of laboratory-confirmed IMD cases reported to the NNDSS in 2018.
• Serogroup determination and molecular typing (porA, ST) of Neisseria meningitidis isolates.
• Antimicrobial susceptibility testing for penicillin, ceftriaxone, rifampicin, and ciprofloxacin.

Main Results:

• Serogroup B (44.2%) and W (36.3%) were the most common serogroups identified in 2018.
• IMD showed a bimodal age distribution, with peaks in children under 5 years and adults aged 45 and over.
• A hypervirulent strain (porA P1.5,2; ST-11) was identified in 44% of typed serogroup W cases.
• Decreased penicillin susceptibility was noted in 93.8% of isolates, though all remained susceptible to ceftriaxone and rifampicin.

Conclusions:

• Serogroup distribution and age-specific incidence of IMD in Australia demonstrate distinct patterns.
• The continued emergence of hypervirulent strains warrants ongoing molecular surveillance and public health vigilance.
• Antimicrobial resistance patterns highlight the importance of monitoring susceptibility to guide treatment strategies.