Serotypes and antibiotic resistance patterns of group B streptococci isolated from pregnant women at Urmia University Hospital, Iran
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Abstract
Background and Objectives: Group B Streptococcus (GBS) is a common bacterium found in the gastrointestinal tract and genitalia of both humans and animals. GBS infections can lead to a range of conditions, including meningitis, pneumonia, and sepsis. The present study aimed to analyze the colonization rate, antibiotic susceptibility, and serotypes of GBS in pregnant women in Urmia, Iran.
Materials and Methods: Following GBS isolation from pregnant women and confirming its presence through PCR, antibiotic susceptibility testing was conducted to assess resistance patterns, followed by amplification of resistance genes (mefA, ermB, ermTR, linB) and molecular serotyping to determine the genetic characteristics of the strains.
Results: Out of 400 samples, 31 (7.75%) were positive for GBS, with 22 (70.97%) showing multidrug resistance. Clindamycin had the highest resistance rate (80.65%), while penicillin showed the lowest (3.23%). Serotypes II and V were the most common (38.71% each), followed by Ia (19.35%) and III (3.23%). The ermB gene was detected in 4 strains, while mefA, ermTR, and linB were not found.
Conclusion: Optimal management of GBS infections in pregnant women necessitates ongoing surveillance and antibiotic stewardship, considering penicillin resistance and observed resistance patterns.
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12. Russell NJ, Seale AC, O'Driscoll M, O'Sullivan C, Bianchi-Jassir F, Gonzalez-Guarin J, et al. Maternal colonization with group B streptococcus and serotype distribution worldwide: systematic review and meta-analyses. Clin Infect Dis 2017; 65(Suppl_2): S100-S111.
13. Sadeh M, Firouzi R, Derakhshandeh A, Bagher Khalili M, 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.
14. Clinical and Laboratory Standards Institute (CLSI) (2018). Performance standards for antimicrobial susceptibility testing. 28th ed. CLSI supplement M100. Wayne (PA): CLSI.
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16. Mousavi SM, Nasaj M, Hosseini SM, Arabestani MR. Survey of strain distribution and antibiotic resistance pattern of group B streptococci (Streptococcus agalactiae) isolated from clinical specimens. GMS Hyg Infect Control 2016; 11: Doc18.
17. Poyart C, Tazi A, Réglier-Poupet H, Billoët A, Tavares N, Raymond J, et al. Multiplex PCR assay for rapid and accurate capsular typing of group B streptococci. J Clin Microbiol 2007; 45: 1985-1988.
18. Dashtizade M, Zolfaghari MR, Yousefi M, Nazari-Alam A. Antibiotic susceptibility patterns and prevalence of Streptococcus agalactiae rectovaginal colonization among pregnant women in Iran. Rev Bras Ginecol Obstet 2020; 42: 454-459.
19. Bobadilla FJ, Novosak MG, Cortese IJ, Delgado OD, Laczeski ME. Prevalence, serotypes and virulence genes of Streptococcus agalactiae isolated from pregnant women with 35-37 weeks of gestation. BMC Infect Dis 2021; 21: 73.
20. Ashary N, Singh A, Chhabria K, Modi D. Meta-analysis on prevalence of vaginal group B streptococcus colonization and preterm births in India. J Matern Fetal Neonatal Med 2022; 35: 2923-2931.
21. Zakerifar M, Kaboosi H, Goli HR, Rahmani Z, Peyravii Ghadikolaii F. Antibiotic resistance genes and molecular typing of Streptococcus agalactiae isolated from pregnant women. BMC Pregnancy Childbirth 2023; 23: 43.
22. Rostami S, Moeineddini L, Ghandehari F, Khorasani MR, Shoaei P, Ebrahimi N. Macrolide-resistance, capsular genotyping and associated factors of group B streptococci colonized pregnant women in Isfahan, Iran. Iran J Microbiol 2021; 13: 183-189.
23. HajiAhmadi P, Momtaz H, Tajbakhsh E. Molecular characterization of Streptococcus agalactiae strains isolated from pregnant women. Sci Rep 2025; 15: 5887.
24. Van Du V, Dung PT, Toan NL, Van Mao C, Bac NT, Van Tong H, et al. Antimicrobial resistance in colonizing group B streptococcus among pregnant women from a hospital in Vietnam. Sci Rep 2021; 11: 20845.
25. Santana FAF, de Oliveira TVL, Filho MBS, da Silva LSC, de Brito BB, de Melo FF, et al. Streptococcus agalactiae: identification methods, antimicrobial susceptibility, and resistance genes in pregnant women. World J Clin Cases 2020; 8: 3988-3998.
26. Ali MM, Woldeamanuel Y, Asrat D, Fenta DA, Beall B, Schrag S, et al. Features of Streptococcus agalactiae strains recovered from pregnant women and newborns attending different hospitals in Ethiopia. BMC Infect Dis 2020; 20: 848.
27. Liu Z, Jiang X, Li J, Ji W, Zhou H, Gong X, et al. Molecular characteristics and antibiotic resistance mechanisms of clindamycin-resistant Streptococcus agalactiae isolates in China. Front Microbiol 2023; 14: 1138039.
28. Savoia D, Gottimer C, Crocilla C, Zucca M. Streptococcus agalactiae in pregnant women: phenotypic and genotypic characters. J Infect 2008; 56: 120-125.
29. Eskandarian N, Ismail Z, Neela V, van Belkum A, Desa MN, Amin Nordin S. Antimicrobial susceptibility profiles, serotype distribution and virulence determinants among invasive, non-invasive and colonizing Streptococcus agalactiae (group B streptococcus) from Malaysian patients. Eur J Clin Microbiol Infect Dis 2015; 34: 579-584.
30. Gizachew M, Tiruneh M, Moges F, Tessema B. Streptococcus agalactiae maternal colonization, antibiotic resistance and serotype profiles in Africa: a meta-analysis. Ann Clin Microbiol Antimicrob 2019; 18: 14.
31. Wang P, Tong JJ, Ma XH, Song FL, Fan L, Guo CM, et al. Serotypes, antibiotic susceptibilities, and multi-locus sequence type profiles of Streptococcus agalactiae isolates circulating in Beijing, China. PLoS One 2015; 10(3): e0120035.
32. Tsai IA, Su Y, Wang YH, Chu C. Alterations in genes rib, scpB and pilus island decrease the prevalence of predominant serotype V, not III and VI, of Streptococcus agalactiae from 2008 to 2012. Pathogens 2022; 11: 1145.
2. Nguyen LM, Omage JI, Noble K, McNew KL, Moore DJ, Aronoff DM, et al. Group B streptococcal infection of the genitourinary tract in pregnant and non-pregnant patients with diabetes mellitus: an immunocompromised host or something more? Am J Reprod Immunol 2021; 86(6): e13501.
3. Jaworowski A, Huras H, Zembala-Szczerba M, Babczyk D, Wolak A, Stettner D, et al. The level of implementation of the prevention program of group B streptococcal infection during pregnancy and in newborns in accordance to the recommendations of the Polish Gynaecological Society - questionnaire survey. Przegl Lek 2016; 73: 632-636.
4. Steer PJ, Russell AB, Kochhar S, Cox P, Plumb J, Gopal Rao G. Group B streptococcal disease in the mother and newborn-a review. Eur J Obstet Gynecol Reprod Biol 2020; 252: 526-533.
5. Numanović F, Smajlović J, Gegić M, Delibegović Z, Bektaš S, Halilović E, et al. Presence and resistance of Streptococcus agalactiae in vaginal specimens of pregnant and adult non-pregnant women and association with other aerobic bacteria. Med Glas (Zenica) 2017; 14: 98-105.
6. Tevdorashvili G, Tevdorashvili D, Andghuladze M, Tevdorashvili M. Prevention and treatment strategy in pregnant women with group B streptococcal infection. Georgian Med News 2015; (241): 15-23.
7. Szymusik I, Kosińska-Kaczyińska K, Pietrzak B, Wielgoś M. Do we need a different approach to GBS screening? Ginekol Pol 2014; 85: 456-460.
8. Ohlsson A, Shah VS. Intrapartum antibiotics for known maternal group B streptococcal colonization. Cochrane Database Syst Rev 2014; (6): CD007467.
9. Verani JR, McGee L, Schrag SJ; Division of Bacterial Diseases, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention (CDC). Prevention of perinatal group B streptococcal disease--revised guidelines from CDC, 2010. MMWR Recomm Rep 2010; 59: 1-36.
10. Berbel D, González-Díaz A, López de Egea G, Càmara J, Ardanuy C. An overview of macrolide resistance in streptococci: prevalence, mobile elements and dynamics. Microorganisms 2022; 10: 2316.
11. Madrid L, Seale AC, Kohli-Lynch M, Edmond KM, Lawn JE, Heath PT, et al. Infant group B streptococcal disease incidence and serotypes worldwide: systematic review and meta-analyses. Clin Infect Dis 2017; 65(Suppl_2): S160-S172.
12. Russell NJ, Seale AC, O'Driscoll M, O'Sullivan C, Bianchi-Jassir F, Gonzalez-Guarin J, et al. Maternal colonization with group B streptococcus and serotype distribution worldwide: systematic review and meta-analyses. Clin Infect Dis 2017; 65(Suppl_2): S100-S111.
13. Sadeh M, Firouzi R, Derakhshandeh A, Bagher Khalili M, 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.
14. Clinical and Laboratory Standards Institute (CLSI) (2018). Performance standards for antimicrobial susceptibility testing. 28th ed. CLSI supplement M100. Wayne (PA): CLSI.
15. Bolukaoto JY, Monyama CM, Chukwu MO, Lekala SM, Nchabeleng M, Maloba MR, et al. Antibiotic resistance of Streptococcus agalactiae isolated from pregnant women in Garankuwa, South Africa. BMC Res Notes 2015; 8: 364.
16. Mousavi SM, Nasaj M, Hosseini SM, Arabestani MR. Survey of strain distribution and antibiotic resistance pattern of group B streptococci (Streptococcus agalactiae) isolated from clinical specimens. GMS Hyg Infect Control 2016; 11: Doc18.
17. Poyart C, Tazi A, Réglier-Poupet H, Billoët A, Tavares N, Raymond J, et al. Multiplex PCR assay for rapid and accurate capsular typing of group B streptococci. J Clin Microbiol 2007; 45: 1985-1988.
18. Dashtizade M, Zolfaghari MR, Yousefi M, Nazari-Alam A. Antibiotic susceptibility patterns and prevalence of Streptococcus agalactiae rectovaginal colonization among pregnant women in Iran. Rev Bras Ginecol Obstet 2020; 42: 454-459.
19. Bobadilla FJ, Novosak MG, Cortese IJ, Delgado OD, Laczeski ME. Prevalence, serotypes and virulence genes of Streptococcus agalactiae isolated from pregnant women with 35-37 weeks of gestation. BMC Infect Dis 2021; 21: 73.
20. Ashary N, Singh A, Chhabria K, Modi D. Meta-analysis on prevalence of vaginal group B streptococcus colonization and preterm births in India. J Matern Fetal Neonatal Med 2022; 35: 2923-2931.
21. Zakerifar M, Kaboosi H, Goli HR, Rahmani Z, Peyravii Ghadikolaii F. Antibiotic resistance genes and molecular typing of Streptococcus agalactiae isolated from pregnant women. BMC Pregnancy Childbirth 2023; 23: 43.
22. Rostami S, Moeineddini L, Ghandehari F, Khorasani MR, Shoaei P, Ebrahimi N. Macrolide-resistance, capsular genotyping and associated factors of group B streptococci colonized pregnant women in Isfahan, Iran. Iran J Microbiol 2021; 13: 183-189.
23. HajiAhmadi P, Momtaz H, Tajbakhsh E. Molecular characterization of Streptococcus agalactiae strains isolated from pregnant women. Sci Rep 2025; 15: 5887.
24. Van Du V, Dung PT, Toan NL, Van Mao C, Bac NT, Van Tong H, et al. Antimicrobial resistance in colonizing group B streptococcus among pregnant women from a hospital in Vietnam. Sci Rep 2021; 11: 20845.
25. Santana FAF, de Oliveira TVL, Filho MBS, da Silva LSC, de Brito BB, de Melo FF, et al. Streptococcus agalactiae: identification methods, antimicrobial susceptibility, and resistance genes in pregnant women. World J Clin Cases 2020; 8: 3988-3998.
26. Ali MM, Woldeamanuel Y, Asrat D, Fenta DA, Beall B, Schrag S, et al. Features of Streptococcus agalactiae strains recovered from pregnant women and newborns attending different hospitals in Ethiopia. BMC Infect Dis 2020; 20: 848.
27. Liu Z, Jiang X, Li J, Ji W, Zhou H, Gong X, et al. Molecular characteristics and antibiotic resistance mechanisms of clindamycin-resistant Streptococcus agalactiae isolates in China. Front Microbiol 2023; 14: 1138039.
28. Savoia D, Gottimer C, Crocilla C, Zucca M. Streptococcus agalactiae in pregnant women: phenotypic and genotypic characters. J Infect 2008; 56: 120-125.
29. Eskandarian N, Ismail Z, Neela V, van Belkum A, Desa MN, Amin Nordin S. Antimicrobial susceptibility profiles, serotype distribution and virulence determinants among invasive, non-invasive and colonizing Streptococcus agalactiae (group B streptococcus) from Malaysian patients. Eur J Clin Microbiol Infect Dis 2015; 34: 579-584.
30. Gizachew M, Tiruneh M, Moges F, Tessema B. Streptococcus agalactiae maternal colonization, antibiotic resistance and serotype profiles in Africa: a meta-analysis. Ann Clin Microbiol Antimicrob 2019; 18: 14.
31. Wang P, Tong JJ, Ma XH, Song FL, Fan L, Guo CM, et al. Serotypes, antibiotic susceptibilities, and multi-locus sequence type profiles of Streptococcus agalactiae isolates circulating in Beijing, China. PLoS One 2015; 10(3): e0120035.
32. Tsai IA, Su Y, Wang YH, Chu C. Alterations in genes rib, scpB and pilus island decrease the prevalence of predominant serotype V, not III and VI, of Streptococcus agalactiae from 2008 to 2012. Pathogens 2022; 11: 1145.
| Files | ||
| Issue | Vol 17 No 5 (2025) | |
| Section | Original Article(s) | |
| DOI | https://doi.org/10.18502/ijm.v17i5.19878 | |
| Keywords | ||
| Streptococcus agalactiae Penicillins Pregnant women Serotyping | ||
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How to Cite
1.
Lotfollahi L, Shahabi Z, Mousarezai Z, Kimyai S, Hemmati A, Shojadel E. Serotypes and antibiotic resistance patterns of group B streptococci isolated from pregnant women at Urmia University Hospital, Iran. Iran J Microbiol. 2025;17(5):702-707.
