Detection of Hypervirulent ST-17 Clone Among Clinical Group B Streptococcus Isolates Using MALDI-TOF MS and PCR

Area of Science:

• Microbiology
• Infectious Diseases
• Neonatal Health

Background:

• Group B Streptococcus (GBS) is a primary cause of neonatal morbidity and mortality.
• Sequence type 17 (ST-17) GBS strains are associated with increased frequency of neonatal invasive disease compared to other sequence types.
• Identifying hypervirulent GBS strains is crucial for effective neonatal infection management.

Purpose of the Study:

• To investigate the prevalence of the hypervirulent ST-17 GBS clone in clinical isolates from Türkiye.
• To evaluate the utility of MALDI-TOF MS for rapid detection of ST-17 GBS.
• To compare MALDI-TOF MS results with PCR and MLST for ST-17 GBS identification.

Main Methods:

• Analysis of 108 clinical GBS isolates from invasive and non-invasive infections.
• Detection of ST-17 GBS using MALDI-TOF MS and polymerase chain reaction (PCR).
• Multilocus sequence typing (MLST) performed on a subset of isolates for confirmation.

Main Results:

• MALDI-TOF MS identified 6 (5.5%) of 108 GBS isolates as ST-17, with a characteristic peak at 7620 Da.
• An additional isolate was identified as ST-17 by PCR, though MLST classified it as ST-1.
• MLST confirmed six isolates as ST-17 or single-locus variants, while other representative isolates were non-ST-17.

Conclusions:

• This study provides the first evidence of a circulating hypervirulent ST-17 GBS clone in Türkiye.
• MALDI-TOF MS demonstrated effectiveness and speed in differentiating ST-17 from non-ST-17 GBS isolates.
• The rapid detection capability of MALDI-TOF MS can aid in the timely management of neonatal infections caused by ST-17 GBS.