Differentiating Streptococcus pseudoporcinus from GBS: could this have implications in pregnancy?

Area of Science:

• Microbiology
• Obstetrics and Gynecology
• Infectious Diseases

Background:

• Streptococcus agalactiae (GBS) is a significant cause of neonatal and maternal infections.
• Streptococcus pseudoporcinus (S. pseudoporcinus) is a distinct bacterium that can be misidentified as GBS in standard tests.
• Accurate differentiation between GBS and S. pseudoporcinus is crucial for appropriate clinical management.

Purpose of the Study:

• To investigate the prevalence of Streptococcus pseudoporcinus colonization during pregnancy.
• To determine the clinical significance and outcomes associated with S. pseudoporcinus colonization.
• To identify predictors of S. pseudoporcinus colonization and compare it with GBS colonization.

Main Methods:

• A retrospective cohort study compared pregnant women colonized with GBS versus S. pseudoporcinus.
• Matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) was used for precise bacterial identification.
• Antibiotic susceptibility testing and chart reviews were conducted to assess outcomes and identify predictors.

Main Results:

• S. pseudoporcinus colonization was found in 1.6% of pregnancies, with 2.5% of GBS-positive tests being false positives.
• Colonization is independently associated with African American race, tobacco use, and high BMI (≥35).
• Preterm birth and preterm premature rupture of membranes were more frequent in women colonized with S. pseudoporcinus compared to GBS.

Conclusions:

• Despite low prevalence, S. pseudoporcinus colonization disproportionately affects African American women.
• S. pseudoporcinus colonization is linked to adverse pregnancy outcomes, specifically preterm birth.
• Accurate diagnostic methods are essential to distinguish S. pseudoporcinus from GBS and manage associated risks.