Colonization rate of Streptococcus Agalactiae in pregnant women in Iran: A systematic review

Document Type : Review Article


1 PhD student in Medical Bacteriology, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran.

2 Associate Professor, Department of Medical Virology, Antimicrobial Resistance Research Center, Mashhad University of Medical Sciences, Mashhad, Iran.


Introduction: Streptococcus agalactiae can be colonized in rectovaginal of pregnant women and subsequently with transmission to infant's results in serious early neonatal diseases such as sepsis and pneumonia. To prevent these complications, antibiotic prophylaxis in pregnant women carrying the bacteria should be performed. There are various statistics about the colonization rate of these bacteria in Iran and the total prevalence is unclear. This review study was performed with aim to evaluate the bacterial colonization in Iran.
Methods: In this review study, colonization rate of Streptococcus agalactiae in pregnant women in Iran was evaluated by search in databases of Google Scholar, Scopus, PubMed, Iran Medex, ISC, ISI Web of Knowledge and MedLib by using the keywords of Streptococcus agalactiae colonization, group B streptococcus colonization, neonatal infection, pregnant women and Iran without time limitation. 32 articles were included in the study based on the rectovaginal colonization rate of pregnant women by Streptococcus agalactiae in different areas of Iran. Data analysis was performed using SPSS software (version 16).
Results: A total of 10548 pregnant women in 17 cities at 32 studies were investigated. Among them, 1568 were colonized with bacteria. The total prevalence rate was estimated 15.5%; the highest and lowest prevalence of Streptococcus agalactiae was observed in Sanandaj (75%) and Kashan (7.6%), respectively.
Conclusion: Screening of Streptococcus agalactiae in all pregnant women at 35-37 weeks of pregnancy and providing epidemiological data to the health care system for preventive measures such as the development of vaccines based on common serotype would be useful. Also, the relationship between Streptococcus colonization and maternal and neonatal complications be evaluated in clinical studies.


  1. Nasri K, Chehrei A, Manavi MS. Evaluation of vaginal group B streptococcal culture results after digital vaginal examination and its pattern of antibiotic resistance in pregnant women. Iran J Reprod Med 2013; 11(12):999-1004.
  2. Rahbar M, Hajia M, Mohammadzadeh M. Urinary tract infections caused by group B streptococcus in adult women: survey of 11800 urine culture results. Iran J Pathol 2012; 7(1):32-7.
  3. Haghshenas Mojaveri M, Zahedpasha Y, Asnafi N, Farhadi J, Haddad G. A survey on the prevalence of group B Streptococcus in pregnant women referred to the obstetrics and gynecology ward at babol Ayatollah Rouhani hospital. Iran J Neonatol 2014; 5(1):23-7.
  4. Malek-Jafarian M, Hosseini FS, Ahmadi AR. Pattern of infection and antibiotic activity among Streptococcus agalactiae isolates from adults in Mashhad, Iran. Rep Biochem Mol Biol 2015; 3(2):89-93.
  5. Nazer MR, Rafiei AE, Nazer E, Khamechi M. Prevalence of group B streptococcus vaginal colonization in the third trimester of pregnancy. J Shahid Sadoughi Univ Med Sci 2011; 19(1):13-23. (Persian).
  6. Aali BS, Abdollahi H, Nakhaee N, Davazdahemami Z, Mehdizadeh A. The association of preterm labor with vaginal colonization of group B streptococci. Int J Reprod BioMed 2007; 5(4):191-4.
  7. Jannati E, Roshani M, Arzanlou MO, Habibzadeh S, Rahimi G, Shapuri R. Capsular serotype and antibiotic resistance of group B streptococci isolated from pregnant women in Ardabil, Iran. Iran J Microbiol 2012; 4(3):130-5.
  8. Fatemi F, Pakzad P, Zeraati H, Talebi S, Asgari S, Akhondi MM, et al. Comparative molecular and microbiologic diagnosis of vaginal colonization by group b streptococcus in pregnant women during Labor. Iran J Basic Med Sci 2010; 13(4):183-8.
  9. Javanmanesh F, Eshraghi N. Prevalence of positive recto-vaginal culture for Group B streptococcus in pregnant women at 35-37 weeks of gestation. Med J Islamic Republic of Iran 2013; 27(1):7-11.
  10. Tajbakhsh S, Norouzi Esfahani M, Emaneini M, Motamed N, Rahmani E, Gharibi S. Identification of Streptococcus agalactiae by fluorescent in situ hybridization compared to culturing and the determination of prevalence of Streptococcus agalactiae colonization among pregnant women in Bushehr, Iran. BMC Infect Dis 2013; 13(1):420.
  11. Rabiei S, Arab M, Yousefi MR. Epidemiologic pattern of vaginal colonization by group B Streptococcus in pregnant women in Hamadan, Central west of Iran. Iran J Med Sci 2006; 31(2):106-8.
  12. Bidgani S, Navidifar T, Najafian M, Amin M. Comparison of group B streptococci colonization in vaginal and rectal specimens by culture method and polymerase chain reaction technique. J Chin Med Assoc 2016; 79(3):141-5.
  13. Hassanzadeh P, Motamedifar M, Gharaghani MN. Carriage rate of group B streptococci in pregnant women in three teaching hospitals in Shiraz, Iran. Med Princ Pract 2011; 20(3):277-82.
  14. Jahed T, Shariati MK, Darabi P, Karimi A. Frequency of group B Streptococcus colonization and antibiogram in women at 35-37 weeks of gestation visited in prenatal clinic of Mahdieh Hospital in 2008. Pejouhandeh J 2011; 16(3):139-43.
  15. Kalantar E. High burden of Group B Streptococcus: an invasive bacterium among pregnant women referring to Health Centers of Sanandaj, Iran. Infect Epidemiol Med 2013; 1(1):15-8.
  16.  Bakhtiari R, Dallal MS, Mehrabadi JF, Heidarzadeh S, Pourmand MR. Evaluation cultur and PCR method for diagnosis of group B Streptococcus Carriage in Iranian Pregnant Women. Iran J Public Health 2012; 41(3):65-70.
  17. Barcaite E, Bartusevicius A, Tameliene R, Kliucinskas M, Maleckiene L, Nadisauskiene R. Prevalence of maternal group B streptococcal colonisation in European countries. Acta Obstet Gynecol Scand 2008; 87(3):260-71.
  18. Nahaei MR, Ghandchilar N, Bilan N, Ghahramani P. Maternal carriage and neonatal colonization of Streptococcus agalactiae in Tabriz, Northwest Iran. Iran J Med Sci 2015; 32(3):177-81.
  19. Hadavand S, Ghafoorimehr F, Rajabi L, Davati A, Zafarghandi N. Frequency of Group B Streptococcal colonization in pregnant women aged 35-37 weeks in clinical centers of Shahed University, Tehran, Iran. Iran J Pathol 2015; 10(2):120-6.
  20. Sadeh M, Firouzi R, Derakhshandeh A, Khalili MB, Kong F, Kudinha T. Molecular characterization of Streptococcus agalactiae isolates from pregnant and non-pregnant women at Yazd University Hospital, Iran. Jundishapur J Microbiol 2016; 9(2):e30412.
  21. Goudarzi G, Ghafarzadeh M, Shakib P, Anbari K. Culture and Real-Time PCR based maternal screening and antibiotic susceptibility for group B Streptococcus: an Iranian experience. Global J Health Sci 2015; 7(6):233-39.
  22. Mashouf RY, Mousavi SM, Rabiee S, Alikhani MY, Arabestani MR. Direct identification of Streptococcus agalactiae in vaginal colonization in pregnant women using polymerase chain reaction. J Comprehen Pediatri 2014; 5(4):e23339.
  23. Fazeli Z, Alipour M, Amir Mozafari N, Ghasemi Nejad Y, Salehi Omran O, Talebjanat M. The survey of Streptococcus agalactiae carriage in pregnant women and determination of antibiotics susceptibity pattern in Amol city. Iran J Med Microbiol 2015; 9(2):20-6. (Persian).
  24. Yasini M, Moniri R, Ghorbaali Z, Ansaripour L, Movahedinejad M, Yadegarsalehi M. Prevalence Rate, Antibiotic Susceptibility And Colonization Risk Factors Of Group B Streptococcus In Genital Tract Of Pregnant Women. Medical Journal of Mashhad University of Medical Sciences. 2014; 57(5): 676-683.  [Persian]
  25. Rohi E, Ghasemi K, Agdam FK. Incidence of Non-Gonococcal Infection in Childbearing and Pregnant Women in Ardabi.2011;12(2):71-76.
  26. Habibzadeh S, Arzanlou M, Jannati E, Asmar M, Azari M, Fardiazar Z. Maternal carriage of group B Streptococcus in Ardabil, prevalence and antimicrobial resistance. Journal of Ardabil University of Medical Sciences. 2010;10(1):14-20.
  27. Fatemi F, Chamani L, Pakzad P, Zeraati H, Rabbani H, Asgari S. Colonization rate of group B Streptococcus (GBS) in pregnant women using GBS agar medium. Acta Medica Iranica. 2009;47(1):25-30.
  28. Seddigheh AF, Reza G, Simin Z. Study on Colonization of Group В Streptococcus (GBS) and Relationship with Perinatal Complication in Pregnant Women Referred to Alzahra Hospital. Research Journal of Biological Sciences. 2008;3(7):726-8.
  29. Mansouri S. Vaginal Colonization of Group В Streptococci During Late Pregnancy in Southeast of Iran: Incidence, Serotype Distribution and Susceptibility to Antibiotics. J Med Sci. 2008;8(6):574-8.
  30. Jahromi BN, Poorarian S, Poorbarfehee S. The prevalence and adverse effects of group B streptococcal colonization during pregnancy. Archives of Iranian medicine.2008;11(6):654-7.
  31. Shshbazian N, Rajabzade A, Alavi SM. Prevalence of colonization with group B streptococcus in the vagina and rectum 37-35 weeks pregnant women and antibiotic susceptibility. Jundishapur Scientific Medical Journal. 2007;6(3):294-297. [Persian]
  32.  Akhlaghi F, Hamedi A, and Naderi Nasab M. Comparison of group B streptococcal colonization in the pregnant diabetic and non-diabetic women. Acta Medica Iranica.2009;47(2)103:103-8.
  33.  Bakhtiari R, Soltandalal Mm, Zaeemi J, Falah J, Mozafari NM, Pormand Mr, Hajikhani S. Evaluation of PCR method to detect carriers of Streptococcus Group B in pregnant women compared with the cultivation. Iranian Journal Of Microbiology.2007;1(2):1-8. [Persian]
  34. Amir Mn, Mansour Gm, Sadr Nb, Farhadi Tl. Survey prevalence of Group B Streptococci in genital tract women in 28-37 weeks pregnancy. 2006. Medical Journal of Gilan University of Medical Sciences. 2006; 59(5): 91-6.  [Persian]
  35. Absalan M, Eslami G, Zandi H, Mosaddegh A, Vakili M, Khalili MB. Prevalence of Recto-Vaginal Colonization of Group B Streptococcus in Pregnant Women. Journal of Isfahan Medical School. 2013;30(220):2367-2375 .
  36. Sarafrazi n, mesdaghinia e, moniri r, mosavi sgh. Evaluation of vaginal hemolytic streptococcus B infection in pregnant women and its association with early neonatal infections during pregnancy. Journal of  kashan Medical School. 2001;18(80):23-27. [Persian]
  37. Kwatra G, Cunnington MC, Merrall E, Adrian PV, Ip M, Klugman KP, et al. Prevalence of maternal colonisation with group B streptococcus: a systematic review and meta-analysis. The Lancet Infectious Diseases. 2016.1-9.
  38. Shirvani F, Shahrochi N, Radfar M, Lakestani D. Estimation of Group B Streptococcus Colonization in High-Risk Neonates by PCR and Standard Culture. Archives of Pediatric Infectious Diseases. 2014;2(2):e17345.
  39. Farhadifar F, Mohammadzadeh P, Alikhani M.Y, Torabi V, Bahmanpor, Kalantar E. High Burden of Group B Streptococcus: An Invasive Bacterium among Pregnant Women Referring to Health Centers of Sanandaj, Iran. Infect. Epidemiol. 2013;1(1):,15-18.
  40. Shirazi M,Abbariki E, Hafizi A, Shahbazi F, Bandari M, Dastgerdy E, et al,. The Prevalence of Group B Streptococcus Colonization in Iranian Pregnant Women and Its Subsequent Outcome. Int J Fertil Steril. 2014;7(4):267-270.
  41. Hamedi H, Akhlaghi F, Seyedi SJ, Kharazmi A. Evaluation of Group B Streptococci Colonization Rate in Pregnant Women and Their Newborn. Acta Medica Iranica, 2012;50(12): 805-808.