Multilocus sequence types in Czech neonatal GBS strains from 2004 to 2008

Area of Science:

• Microbiology
• Genetics
• Neonatal Health

Background:

• Streptococcus agalactiae (Group B Streptococcus) is a leading cause of neonatal infections.
• Understanding the genetic diversity and invasive potential of S. agalactiae is crucial for effective prevention and treatment strategies.
• Multilocus sequence typing (MLST) is a powerful tool for characterizing bacterial population structures.

Purpose of the Study:

• To perform the first MLST analysis of Czech neonatal S. agalactiae isolates.
• To determine if Czech isolates belong to the invasive clonal complex CC17.
• To investigate the relationship between serotypes and sequence types (STs) in invasive isolates.

Main Methods:

• Multilocus sequence typing (MLST) was performed on 77 neonatal S. agalactiae isolates from the Czech Republic.
• Sequence types were assigned to clonal complexes (CCs).
• Serotype-sequence type associations were analyzed.

Main Results:

• Twelve sequence types were identified, assigned to 5 clonal complexes.
• A high degree of sequence type variability was observed for most serotypes.
• Three sequence types (ST17, ST23, ST19) accounted for 83% of invasive isolates.
• ST17 was exclusively associated with serotype III.
• The 'hyperinvasive' ST17 was found in 85% of cerebrospinal fluid isolates and 32% of blood isolates.

Conclusions:

• Czech neonatal S. agalactiae isolates exhibit genetic diversity, with specific sequence types dominating invasive disease.
• The clonal complex CC17, particularly ST17, is a significant factor in invasive neonatal infections, especially those involving serotype III and central nervous system disease.
• MLST provides valuable insights into the population structure and invasive potential of S. agalactiae in neonates.