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.


Raabe VN, Shane AL. Group B Streptococcus (Streptococcus agalactiae). Microbiol Spectr. 2019;7(2): 10.1128/microbiolspec.GPP3-0007-2018.

Sadowy E, Matynia B, Hryniewicz W. Population structure, virulence factors and resistance determinants of invasive, non-invasive and colonizing Streptococcus agalactiae in Poland. J Antimicrob Chemother 2010;65(9):1907–14.

Carreras-Abad C, Ramkhelawon L, Heath PT, Le Doare K. A Vaccine Against Group B Streptococcus: Recent Advances. Infect Drug Resist. 2020; 13:1263-72.

Creti R, Fabretti F, Orefici G, von Hunolstein C. Multiplex PCR assay for direct identification of group B streptococcal a-protein-like protein genes. J Clin Microbiol 2004; 42: 1326–9.

Lindahl G, Stalhammar-Carlemalm M, Areschoug T. Surface proteins of Streptococcus agalactiae and related proteins in other bacterial pathogens. Clin Microbiol Rev 2005; 18: 102–27.

Baker CJ, Edwards MS. Group B streptococcal conjugate vaccines. Arch Dis Child 2003; 88: 375–8.

Johri AK, Paoletti LC, Glaser P, Dua M, Sharma PK, Grandi G et al. Group B Streptococcus: global

incidence and vaccine development. Group B Streptococcus: global incidence and vaccine development. Nat Rev Microbiol 2006; 4:932–42.

Phares CR, Lynfield R, Farley MM, Mohle-Boetani J, Harrison HL, Petit S, et al. Epidemiology of invasive group B streptococcal disease in the United States, 1999–2005. JAMA 2008; 299:2056–65.

Andrews JI, Diekema DJ, Hunter SK, Rhomberg PR, Pfaller MA, Jones RN et al. Group B streptococci causing neonatal bloodstream infection: antimicrobial susceptibility and serotyping results from SENTRY centers in the Western Hemisphere. Am J Obstet. Gynecol 2000:183;859–62.

Weisner AM, Johnson AP, Lamagni TL, Arnold E, Warner M, Hearth PT et al. Characterization of group B streptococci recovered from infants with invasive disease in England and Wales. Clin Infect Dis 2004; 38:1203–8.

Ueno H, Yamamoto Y, Yamamichi A, Kikuchi K, Kobori S, Miyazaki M. Characterization of Group B Streptococcus Isolated from Women in Saitama City, Japan. Japanese Journal of Infectious Diseases 2012;65(6):516–21.

Ekin IH, Gurturk K. Characterization of bovine and human group B streptococci isolated in Turkey. J Med Microbiol 2006;55(5):517–21.

Ferrieri P, Baker CJ, Hillier SL, Flores AE. Diversity of surface protein expression in group B streptococcal colonizing & invasive isolates. Indian J Med Res 2004; 119:191–6.

Terakubo S, Ichiman Y, Takemura H, Yamamoto H, Shimada J, Nakashima H. Serotypes and antibody levels of group B streptococci in pregnant women. Kansenshōgaku Zasshi 2003;77(3):121–6.

Tsolia M, Psoma M, Gavrili S, Petrochilou V, Michalas S, Legakis N et al. Group B streptococcus colonization of Greek pregnant women and neonates: prevalence, risk factors and serotypes. Clin Microbiol Infect 2003;9(8):832–8.

Gherardi G, Imperi M, Baldassarri L, Pataracchia M, Alfarone G, Recchia S, et al. Molecular Epidemiology and Distribution of Serotypes, Surface Proteins, and Antibiotic Resistance among Group B Streptococci in Italy. J Clin Microbiol 2007;45(9):2909–16.

Topkaya AE, Ciragil P, Sezer O, Karateke A, Küçükercan M. The Serotype Distrubition of Group B Streptococci Isolated from Pregnant Women. Türk Mikrobiyol Cem Derg.2005; 35:81-4

Eren A, Küçükercan M, Oğuzoğlu N, Unal N, Karateke A. The carriage of group B streptococci in Turkish pregnant women and its transmission rate in newborns and serotype distribution. Turk J Pediatr.2005;47(1):28–33.




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.



Original Article