Maureen Grundy1, Nuntra Suwantarat2, Mayer Rubin3, Renee Harris3, Ann Hanlon3, Tsigereda Tekle3, Brandon Ellis3, Karen Carroll3, Frank Witter4. 1. Department of Gynecology and Obstetrics, Division of Maternal Fetal Medicine, Johns Hopkins University School of Medicine, Baltimore, MD; Department of Gynecology and Obstetrics, Division of Maternal Fetal Medicine, St. Joseph Medical Center, Towson, MD. Electronic address: maureen.grundy@umm.edu. 2. Department of Pathology, Division of Microbiology, Johns Hopkins University School of Medicine, Baltimore, MD; Chulabhorn International College of Medicine, Thammasat University, Pathumthani, Thailand. 3. Department of Pathology, Division of Microbiology, Johns Hopkins University School of Medicine, Baltimore, MD. 4. Department of Gynecology and Obstetrics, Division of Maternal Fetal Medicine, Johns Hopkins University School of Medicine, Baltimore, MD.
Abstract
BACKGROUND: Streptococcus agalactiae (GBS) is a common pathogen known to cause neonatal and maternal infectious morbidity. Streptococcus pseudoporcinus (S pseudoporcinus) is a separate, recently identified β-hemolytic gram-positive coccus that can cause false-positive results on standard GBS agglutination testing assays. OBJECTIVE: To determine the prevalence and clinical implications of Streptococcus pseudoporcinus colonization in pregnancy. MATERIALS AND METHODS: This is a 2-year retrospective cohort study comparing pregnant women colonized with GBS to those colonized with S. pseudoporcinus. A proteomics method of identification, namely, matrix-assisted laser desorption ionization time-of-flight mass spectrometry, was used to distinguish between S. pseudoporcinus and GBS colonization. Antibiotic susceptibility testing was carried out on all specimens. Maternal and neonatal chart reviews were conducted to identify predictors of S. pseudoporcinus colonization and to compare maternal and neonatal outcomes. RESULTS: S. pseudoporcinus colonization occurred in 1.6% of all pregnancies. A total of 2.5% of all GBS-positive results by agglutination assay were false positive, instead reflecting S. pseudoporcinus colonization. Clindamycin resistance among S. pseudoporcinus isolates is uncommon. S. pseudoporcinus colonization in pregnancy is independently associated with African American race, tobacco use, and body mass index ≥35. Preterm premature rupture of membranes or spontaneous preterm birth was more common in patients colonized with S. pseudoporcinus. CONCLUSION: Although the prevalence of S. pseudoporcinus colonization is low, it primarily occurs in African American women and is associated with preterm premature rupture of membranes or spontaneous preterm birth when compared to individuals colonized with GBS.
BACKGROUND:Streptococcus agalactiae (GBS) is a common pathogen known to cause neonatal and maternal infectious morbidity. Streptococcus pseudoporcinus (S pseudoporcinus) is a separate, recently identified β-hemolytic gram-positive coccus that can cause false-positive results on standard GBS agglutination testing assays. OBJECTIVE: To determine the prevalence and clinical implications of Streptococcus pseudoporcinus colonization in pregnancy. MATERIALS AND METHODS: This is a 2-year retrospective cohort study comparing pregnant women colonized with GBS to those colonized with S. pseudoporcinus. A proteomics method of identification, namely, matrix-assisted laser desorption ionization time-of-flight mass spectrometry, was used to distinguish between S. pseudoporcinus and GBS colonization. Antibiotic susceptibility testing was carried out on all specimens. Maternal and neonatal chart reviews were conducted to identify predictors of S. pseudoporcinus colonization and to compare maternal and neonatal outcomes. RESULTS: S. pseudoporcinus colonization occurred in 1.6% of all pregnancies. A total of 2.5% of all GBS-positive results by agglutination assay were false positive, instead reflecting S. pseudoporcinus colonization. Clindamycin resistance among S. pseudoporcinus isolates is uncommon. S. pseudoporcinus colonization in pregnancy is independently associated with African American race, tobacco use, and body mass index ≥35. Preterm premature rupture of membranes or spontaneous preterm birth was more common in patients colonized with S. pseudoporcinus. CONCLUSION: Although the prevalence of S. pseudoporcinus colonization is low, it primarily occurs in African American women and is associated with preterm premature rupture of membranes or spontaneous preterm birth when compared to individuals colonized with GBS.