Hypervirulent Clone of Group B Streptococcus Serotype III Sequence Type 283, Hong Kong, 1993-2012

Area of Science:

• Microbiology
• Epidemiology
• Infectious Diseases

Background:

• Group B Streptococcus (GBS) is a leading cause of invasive bacterial infections in neonates and adults.
• Specific clones of GBS can exhibit hypervirulence and distinct epidemiological characteristics.
• Understanding GBS epidemiology is crucial for public health interventions.

Purpose of the Study:

• To characterize a hypervirulent clone of GBS serotype III, subtype 4, sequence type 283.
• To investigate the clinical presentation, mortality, and seasonality of invasive disease caused by this clone in Hong Kong.
• To explore potential environmental links, such as diseased fish, associated with the clone.

Main Methods:

• Molecular typing (serotyping, multilocus sequence typing) to identify the GBS clone.
• Retrospective analysis of invasive GBS isolates from Hong Kong (1993-2012).
• Clinical data review to assess disease patterns, including meningitis and mortality.

Main Results:

• Identification of a hypervirulent GBS clone (serotype III, subtype 4, ST-283) responsible for invasive disease.
• The clone demonstrated a predilection for causing meningitis.
• High mortality rates were associated with infections caused by this clone, with increased prevalence observed during summer.
• A link was established between this clone and diseased fish from freshwater fish farms.

Conclusions:

• A specific hypervirulent GBS clone (ST-283) emerged as a significant cause of invasive meningitis in Hong Kong.
• The clone's association with diseased fish suggests a potential zoonotic transmission route.
• The findings highlight the importance of monitoring GBS strains and potential environmental sources for public health surveillance.