Investigation of Streptococcus agalactiae serotypes in clinical samples

Streptococcus agalactiae serotypes




Infection, colonization, serotype, Streptococcus agalactiae


Objective: A key contributor to neonatal early-onset sepsis, postpartum maternal sepsis, and infant late-onset invasive infections is Streptococcus agalactiae (group B Streptococcus; GBS). GBS may also result in bone and joint infections, bacteremia, endocarditis, pneumonia, and infections of the skin and soft tissues in adults. The bacterial polysaccharide capsule may distinguish between ten GBS serotypes (Ia, Ib, and II–IX). In order to reduce maternal colonization and prevent transmission to neonates, GBS capsular polysaccharide vaccines have been investigated. We aimed to detect the differences of the polysaccharide capsules among GBS isolates.

Methods: This study used GBS isolates from several clinical specimens in the Microbiology Laboratory at Marmara University Hospital in Istanbul. Fifty of the isolates were colonized (37 genital site, 13 throat swab), and 50 of the isolates were infectious (33 urine, 7 blood, 2 respiratory specimens, and 4 wound swab specimens, 4 sterile body fluids). The serotypes of GBS isolates were determined by detecting visible agglutination when specific GBS capsule antigens reacted with serotype monospecific antibodies.

Results: Colonized strain distribution values for  serotype Ia,  serotype II,  serotype III, serotype Ic, serotype R,  serotype V, serotype IV,  serotype II/R,  serotype III/R, and  non-serotyping stains were 12 (24%), 11 (22%), 7 (14%), 3 (6%), 3 (6%) , 2 (4%), 1 (2%), 2 (4%), 1 (2%), 8 (16%) respectively. Causative agents distribution values for   serotype II, serotype Ia, serotype III, serotype R, serotypes IV and serotype VIII, II / R, III / R, and non-serotyping stains were 15 (30%), 13 (26%), 10 (20%), 2 (4%), 1 (2%), 1 (2%), 3 (6%), 2 (4%) and 2 (4%)  respectively.

Conclusion: Serotype Ia, serotype II, and serotype III were the common serotypes in our clinical isolates but molecular-based studies associated with GBS population are needed in our country.


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How to Cite

Arabacı, Çiğdem, Dal, T., Ekin, İsmail H., & Babacan, F. (2023). Investigation of Streptococcus agalactiae serotypes in clinical samples: Streptococcus agalactiae serotypes. The Injector, 2(1), 9–15.