Use of MALDI-TOF mass spectrometry for rapid identification of group B Streptococcus on chromID Strepto B agar.

BACKGROUND

Group B Streptococcus (GBS) is a known leading causative pathogen of neonatal infection. Efficient screening and identification of women colonized with GBS is important for the prevention of invasive neonatal infections.

METHODS

A total of 628 vaginal/rectal specimens were collected from pregnant women in Beijing, China. The chromogenic medium chromID Strepto B agar (STRB) was evaluated for its reliability in screening GBS from the vaginal/rectal swabs; results were compared to those of blood agar plates (BAP). Furthermore, matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) was used to confirm the colonies suspected of being GBS on STRB.

RESULTS

STRB showed excellent performance for GBS detection and outperformed BAP due to its higher sensitivity. Furthermore, MALDI-TOF MS could reliably differentiate the putative GBS isolates on STRB.

CONCLUSIONS

This study demonstrated that STRB combined with MALDI-TOF MS is a fast, sensitive, and accurate method for the identification of GBS-colonized pregnant women.