Determinants of Group B streptococcal virulence potential amongst vaginal clinical isolates from pregnant women

Autoři: Lindsey R. Burcham aff001;  Brady L. Spencer aff001;  Lauryn R. Keeler aff002;  Donna L. Runft aff003;  Kathryn A. Patras aff002;  Melody N. Neely aff003;  Kelly S. Doran aff001
Působiště autorů: Department of Immunology and Microbiology, University of Colorado, Aurora, CO, United States of America aff001;  Department of Biology, San Diego State University, San Diego, CA, United States of America aff002;  Department of Molecular & Biomedical Sciences, University of Maine, Orono, ME, United States of America aff003
Vyšlo v časopise: PLoS ONE 14(12)
Kategorie: Research Article
doi: 10.1371/journal.pone.0226699


Streptococcus agalactiae, also known as Group B Streptococcus (GBS), is a Gram-positive bacterium isolated from the vaginal tract of approximately 25% of women. GBS colonization of the female reproductive tract is of particular concern during pregnancy as the bacteria can invade gestational tissues or be transmitted to the newborn during passage through the birth canal. Infection of the neonate can result in life-threatening pneumonia, sepsis and meningitis. Thus, surveillance of GBS strains and corresponding virulence potential during colonization is warranted. Here we describe a panel of GBS isolates from the vaginal tracts of a cohort of pregnant women in Michigan, USA. We determined that capsular serotypes III and V were the most abundant across the strain panel, with only one isolate belonging to serotype IV. Further, 12.8% of strains belonged to the hyper-virulent serotype III, sequence type 17 (ST-17) and 15.4% expressed the serine rich repeat glycoprotein-encoding gene srr2. Functional assessment of the colonizing isolates revealed that almost all strains exhibited some level of β-hemolytic activity and that ST-17 strains, which express Srr2, exhibited increased bacterial adherence to vaginal epithelium. Finally, analysis of strain antibiotic susceptibility revealed the presence of antibiotic resistance to penicillin (15.4%), clindamycin (30.8%), erythromycin (43.6%), vancomycin (30.8%), and tetracycline (94.9%), which has significant implications for treatment options. Collectively, these data provide important information on vaginal GBS carriage isolate virulence potential and highlight the value of continued surveillance.

Klíčová slova:

Antibiotic resistance – Antibiotics – Epithelial cells – Erythromycin – Penicillin – Tetracyclines – Vancomycin – Clindamycin


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