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Distribution of Streptococcus agalactiae Among Iranian Women from 1992 to 2018: A Systematic Review and Meta-Analysis


avatar Maryam Sadeh ORCID 1 , avatar Amin Salehi-Abargouei ORCID 2 , avatar Nastaran Azartoos ORCID 3 , avatar Farzaneh Mirzaei ORCID 4 , avatar Mohammad Bagher Khalili ORCID 3 , *

1 Department of Laboratory Sciences, Faculty of Paramedical Sciences, Shahid Sadoughi University of Medical Sciences, Yazd, Iran

2 Nutrition and Food Security Research Center, Department of Nutrition, Shahid Sadoughi University of Medical Sciences, Yazd, Iran

3 Department of Microbiology, Faculty of Medicine, Shahid Sadoughi University of Medical Sciences, Yazd, Iran

4 Department of Parasitology, Faculty of Medicine, Shahid Sadoughi University of Medical Sciences, Yazd, Iran

How to Cite: Sadeh M, Salehi-Abargouei A, Azartoos N, Mirzaei F , Khalili M B. Distribution of Streptococcus agalactiae Among Iranian Women from 1992 to 2018: A Systematic Review and Meta-Analysis. Jundishapur J Microbiol. 2020;13(7):e102314.
doi: 10.5812/jjm.102314.


Jundishapur Journal of Microbiology: 13 (7); e102314
Published Online: September 27, 2020
Article Type: Systematic Review
Received: March 9, 2020
Revised: July 22, 2020
Accepted: July 25, 2020



Group B Streptococcus has the capacity of being colonized in the rectovaginal organ of women and causes infections in a mother and her fetus, thereby leading to neonatal diseases.

Evidence Acquisition:

The aim of this review was to summarize all of the relevant articles published to highlight the prevalence of group B Streptococcus colonization or infection in different regions of Iran. A systematic literature review was conducted by searching PubMed, Scopus, Web of Science (ISI), ScienceDirect, Google Scholar, and domestic databases for papers published in English or Persian from 1992 up to July 2019, concerning the prevalence of group B Streptococcus among Iranian women. All information regarding year, location of cases, frequency, author’s name, date of publication, participants, pregnancy period, sampling, and quality assessment were recorded. Summary effects were derived using the random effects model.


Among 61 suitable papers, data revealed that 36,807 cases of pregnant and non-pregnant women had been tested for group B Streptococcus during 1992-2018. Overall, 11.9% of pregnant and 5.3% of non-pregnant women were positive. Further results were as follows: vaginal, recto-vaginal, rectal, and endocervical colonization rates were 12.9%, 9.7%, 18.5%, and 3.7%, respectively. Group B Streptococcus incidence was the highest in Sanandaj (61.5%), and the lowest in Tabriz (1.8%).


Although the prevalence distribution in Iran seems to be acceptable, more investigations are needed to represent the real incidence of group B Streptococcus around the country. In addition, a program with a standard lab technique is needed to screen pregnant women for further treatment before birth.

1. Context

As group B Streptococcus is a pathogen commonly found in rectovaginal mucosa of pregnant women, it appears reasonable to label this bacterium as a cause of neonatal diseases at birth (1). Several investigations have revealed that about 10 - 40% of healthy women carry group B Streptococcus in their vagina and/or rectum. Much as the bacterium threatens the fetus in pregnant women, it can also induce infection of the endometrium or amniotic membrane, bacteremia, as well as sepsis and meningitis in susceptible women (2, 3). Since 1970, the etiological role of group B Streptococcus in diseases was highlighted, especially with regard to its ability to cause newborn infections. Recently, two kinds of infantile diseases have been attributed to group B Streptococcus; early-onset diseases and late-onset diseases. The early-onset diseases are usually manifested during the first week after birth, while late-onset diseases may appear 2 - 3 months after birth. Pneumonia and sepsis are both attributed to early-onset diseases; however, late-onset diseases likely engender meningitis in newborn infants.

Albeit different structures have been identified as group B Streptococcus virulence factors, a polysaccharide capsule is known to carry the most important role in this regard (4). It has antiphagocytic function. Other virulence factors include secreted hemolysin, superoxide dismutase, D-alanylated lipoteichoic acid, and some of the surface proteins such as the surface-localized protease CspA. Although surface proteins of Streptococcus agalactiae may have considerable roles during various stages of infection, they attract more and more importance regarding the development of a vaccine. Adhesion to epithelial cells, interactions with human extracellular matrix or plasma proteins, and escape from host immunity are other possible roles of surface proteins of group B Streptococcus (5).

Based on the proportion of cps, group B Streptococcus has been classified into 10 serotypes; Ia, Ib, and II-IX (1, 6). The prevalence rate of group B Streptococcus infections in both pregnant and non-pregnant women varies widely depending on the population studied; however, group B Streptococcus is usually isolated from 10% - 30% of women. In Iran, an estimated average of 9.8% of women is rectovaginally infected; however, the colonization rate of their neonates at birth is not clearly known (7). Some authors believe that about 50 - 75% of infants are exposed to the organism during the birth process (8-10). The major infant’s diseases are attributed to meningitis and septicemia (11, 12). Furthermore, transmission of group B Streptococcus infection to infants at the time of birth, other group B Streptococcus-related infection complications, including premature rupture of membrane, low birth weight, and preterm labor may develop during pregnancy (13).

2. Evidence Acquisition

In the present study, almost all of the literature published from 1992 to July 2019 were reviewed to determine the prevalence of group B Streptococcus carrier state in different regions of Iran. In addition, this study shows the relative frequency of group B Streptococcus positivity with respect to geographical area, date of sampling, and type of the swab specimen.

2.1. Search Strategy

The strategy employed for identifying group B Streptococcus prevalence was searching in PubMed, Scopus, Web of Science (ISI), ScienceDirect, Google Scholar, and domestic databases for papers published in English or Persian. Terms such as S. agalactiae, group B Streptococcus, S. agalactiae, Streptococcus group B, and Iran were used as keywords to find the relevant published works. In order to find the maximum number of related papers and also gray literature, three local search engines, including the Iranian Scientific Information Database (, Medlib (, and Magiran ( were used. No limitations were applied when searching the mentioned databases. Extracted references were all reviewed, and the irrelevant titles/abstracts were excluded from the collection. The study selection process was handled by three researchers (MS, AS, NA). To reach a consensus on the selection of the relevant articles, any disagreement was discussed by the team members.

2.2. Inclusion Criteria

The following publications were identified as eligible to be included in the present systematic review and meta-analysis:

A) Investigations assessing the prevalence of S. agalactiae in the Iranian women,

B) Group B Streptococcus sampling from the vaginal, rectovaginal, endocervical, and rectal regions as well as the urine, and

C) Using culturing and/or PCR method as techniques applied for the detection of group B Streptococcus.

2.3. Exclusion Criteria

Studies were excluded if:

A) They had failed to use a standard method for group B Streptococcus isolation,

B) They had an irrelevant source of sampling (from men, animal, etc.),

C) They were review, meta-analysis or systematic review, or a duplicate publication of the same study.

2.4. Data Collection

Two authors conducted the data extraction, and the following information was collected: The first author’s name and the date of publication, the participants’ status, including the pregnancy period, geographic location, group B Streptococcus isolation, and finally, the number of group B Streptococcus carriers were all noted for further investigation. Any disagreement as for data collection was discussed by the colleagues to reach the final decision (Figure 1).

2.5. Quality Assessment

In this study, a checklist recommended by Hoy et al. (14) was used for the evaluation of the methodological quality. The checklist consisted of nine questions, representing the sampling-related information, technique of sampling, the response rate, the technique applied for data collection, tools for measurement, definition of cases, and the statistical method. Each question was scored 1 or 0, defined as low- or high-risk bias, respectively. Scores 0 to 9 were selected and defined as follows: 0 to 3 as “high-risk”, 4 to 6 “moderate-risk”, and 7 to 9 as “low-risk” bias.

2.6. Limitations

The overall prevalence of group B Streptococcus carriers in our query could not be determined comprehensively. Different factors such as geographical region, collection of samples, site of sampling, socioeconomic status, and microbiological methods all contributed to the results obtained. Also, due to lack of group B Streptococcus prevalence works in some provinces such as Golestan, Semnan, Mazandaran, Zanjan, Qom, South Khorasan, North Khorasan, Sistan and Baluchestan, Hormozgan, Kohgiluyeh and Boyer-Ahmad, Alborz, Qazvin, and West Azarbaijan, this review paper failed to present a full account of group B Streptococcus prevalence in Iran (Figure 2).

Figure 2. Incidence of Group B streptococcus-positive in different cities in Iran. Source: Map of Iran powered by (Note: Rect, rectovaginal; Vag, vaginal)

2.7. Statistical Analysis

The total number of the participants and the number of samples with S. agalactiae were used to calculate the event rate and confidence interval. The summary estimates were derived using the DerSimonial and Laird random effects model by taking inter-study heterogeneity into account. The I-squared and Cochran’s Q tests were used to assess heterogeneity between the studies. Subgroup analysis was used to explore the prevalence rates according to the sampling year, the province in which the study was conducted, and the quality of studies. Sensitivity analysis was carried out to explore the extent to which the overall calculations might depend on a specific study. All analyses were performed using the STATA software version 11.2 (STATA Corp, College Station, TX, USA).

3. Results

According to Databases, 927 articles were selected, among which 563 duplicated articles were excluded. Following reviewing all abstracts of the published works, 292 articles were deleted because of being irrelevant. Full texts of 82 articles were carefully considered, and again, 21 articles that were directly related to infertile women, neonates, adults, and those with ambiguous methods were all excluded from the study. Overall, the remaining 61 articles were approved for further investigation (Figure 1).

3.1. Prevalence of Group B Streptococcus in Iranian Women

Extraction of the information of these articles revealed 36,807 pregnant and non-pregnant women had been examined for group B Streptococcus detection during 1992 - 2018, out of which 2,930 cases (9.7%) were found positive for group B Streptococcus (Table 1). Observed data demonstrated the prevalence of group B Streptococcus among pregnant women to be 11.9% (95% CI: 0.103 - 0.135). Based on swab sampling technique, positive cases were found as the following: (1) vaginal samples with 34 studies (12.9%) (95% CI: 0.103 - 0.155), (2) recto-vaginal samples with 25 studies (9.7%) (95% CI: 0.075 - 0.120), rectum samples with 10 studies (18.5%) (95% CI: 0.096 - 0.275), endocervical samples with one study (3.7%) (95% CI: -0.003 - 0.077), vaginal and urine with one study (6.1%) (95% CI: 0.030 - 0.092), and urine with three studies (2.3%) (95% CI: 0.001 - 0.044). When the recorded data regarding distribution of group B Streptococcus among non-pregnant women were extracted, 5.3% (95% CI: 0.034 - 0.072) of the cases were identified as group B Streptococcus colonized.

Table 1. Characteristics of the Studies Included in the Systematic Review and Meta-Analysis
First Author (Ref. No.)Place (City)Year (yr)AgePregnancyPregnancy Age (wk)Swab SamplesIdentification MethodSample SizeNo. Positive GBSCarriers (%)Quality Assessment
Aali (15)Kerman200525.6Preg38-40VagCult10576.7Low-risk
Absalan (16)Yazd200215-40PregRecto-VagCult. PCR2504919.6Low-risk
Ahmadi (17)Sanandaj201719-43Preg35-37EndocervicalPCR10943.7Moderate-risk
Akhlaghi (18)Mashhad2007NAPreg33-37VagCult4337Moderate-risk
Arzanlou (2)Ardabil2008NAPreg35-37Recto- VagCult4205613.3Low-risk
Bakhtiari (19)Tehran2011NAPreg28-38Recto- VagCult. PCR375359.3Moderate-risk
Bidgani (20)Ahvaz2013-201416-45Preg28-38VagCult. PCR1373827.7Moderate-risk
PregRectCult. PCR1374230.7Moderate-risk
Bornasi (21)Arak2012NAPreg35-37VagCult. PCR5006012Moderate-risk
Soltan Dalal (22)Tehran2008NAPreg35-37Recto- VagCult. PCR125108Low-Risk
Darabi (23)Tehran2014-201518-35Preg35-37Recto- VagCult1862211.8Moderate-risk
Daramroodi (24)Kermanshah2017NAPreg35-37VagCult. PCR10055Moderate-risk
Fatemi (25)Tehran200816-40Preg35-37VagCult, PCR3306820.6Moderate-risk
Fazeli (26)Amol2013NAPreg35-37VagCult, PCR10044Moderate-risk
RectCult, PCR10033Moderate-risk
Recto- VagCult, PCR10033Moderate-risk
Frouhesh (27)Tehran2011-2012NANon-preg-UrineCult50001042.1High-risk
Ghanbarzadeh (28)Birjand2013-201416-37Preg30Recto- VagCult500265.2Moderate-risk
Goudarzi (29)Khorramabad2012NAPreg35-37Recto- VagCult, Real-time PCR1001717Moderate-risk
Habibzadeh (30)Ardabil2010NAPreg35-37VagCult420194.5Moderate-risk
Recto- VagCult420245.7Moderate-risk
Hadavand (31)Tehran2010-1115-44Preg35-37Recto- VagCult21073.3Moderate-risk
Hamedi (32)Mashhad2008-200915-39Preg34-40Recto- VagCult200126Moderate-risk
Hassanzadeh (33)Shiraz2006-200719-35Preg< 20Recto- VagCult3104313.9Low-risk
Jannati (2)Ardabil2012NAPreg35-37Recto- VagCult4205613.3Moderate-risk
Javadi (34) Isfahan2004NAPreg35-37Recto- VagCult1703118.2
Javanmanesh (35)Tehran201216-42Preg35-37Recto- VagCult102823422.8Low-risk
Kabiri (36)Jahrom201416-40Preg35-37VagCult4036616.4Low-risk
Recto- Vag71.7Low-risk
Kalantar (37)Sanandaj2011-201218-37Preg28-38VagPCR20012361.5Moderate-risk
Kasraeian (38)Shiraz200718-36Preg18UrineCult38910.3Low-risk
Khoshkhoutabar (39)Arak2013Preg35-37Recto- VagCult268145.2Moderate-risk
Malek-Jafarian (40)Mashhad201515-40Non-pregUrine VagCult1200463.8Moderate-risk
Mansouri (41)Kerman2006-200720-35Preg35-37VagCult602559.1Moderate-risk
Mashouf (42)Hamadan2013-2014NAPreg35-37VagCult. PCR203157.4Moderate-risk
Mobasheri (43)Ardal201017-38Preg0-40VagCult8522.3Moderate-risk
Nakhaei Moghaddam (44)Mashhad2005-200716-40Preg35-37VagCult2012210.9Moderate-risk
Mohamadi (45)Ilam,2014-201516-42Preg< 35VagCult9044.4Moderate-risk
Mousavi (46)Hamadan2013-2014NAPreg35-37VagCult. PCR203157.4Moderate-risk
Saghafi (47)Mashhad2015-201615-42Preg27-37VagCult20032Moderate-risk
Nahaei (13)Tabriz2001-2002NAPregNA*VagCult965171.8Moderate-risk
Namavar Jahromi (48)Shiraz200314-45Preg> 24Recto- VagCult11971109.2Moderate-risk
Nasri (49)Arak201016-39Preg35-37VagCult1863016.1Moderate-risk
Nazari (50)Yazd2015-201615-40PregNAVagCult3465716.5Moderate-risk
Nazer (51)Khorram Abad200918-39Preg28-37VagCult1001414Low-risk
Pirouz (52)Tehran199215-43Preg> 37VagCult2003417Moderate-risk
Rabiee (53)Hamadan200618-35Preg> 20VagCult54414526.7Moderate-risk
Rahbar (54)Tehran201026.6 ± 19.37 (mean)PregNAUrineCult11800190.2Moderate-risk
Sadeh (9)Yazd2013-201415-40PregNARecto- VagCult. PCR2373012.7Moderate-risk
Non-Preg-Recto- VagCult. PCR4137016.9Moderate-risk
Zarean Seyyed (55)Isfahan2010-201117-42Preg37RectCult1783016.9Low-risk
17-3620-37 (Preterm labor)RectCult1515536.4Low-risk
17-3620-37 (Preterm labor)VagCult1515939.1Low-risk
Sharifi (56)Tehran2011NAPreg35-37Recto- VagCult250218.4Moderate-risk
Shirazi (57)Tehran2009-201119-50Preg35-37VagCult980484.9Low-risk
Tajbakhsh (58)Bushehr2010-201126.39 ± 5.33 meanPreg35-42VagCult285279.5Low-risk
Yasini (59)Kashan2011-201216-45Preg28-37VagCult382369.4Moderate-risk
Zamanzad (60) (unpublished Persian article)Shahrekord2000NAPregVagCult62411017.6Moderate-risk
Amirmozafari (61)Rasht2005Preg28-37VagCult1001515High-risk
Haghshenas Mojaveri (62)Babol201425.9 ± 4.2 (mean)Preg35-37VagCult400317.8Low-risk
Recto- VagCult400102.5Low-risk
Jahed (63)Tehran2008NAPreg35-37Recto- VagCult246135.3Moderate-risk
Khataie (64)Tehran1998NAPreg37VagCult1912814.7Moderate-risk
Nasrollahi1 (65)Sari2018< 25-30 >Preg35-37Vag, UrineCult, PCR246156.1Moderate-risk
Rostami (66)Isfahan201529.35 ± 5.509 (mean)Preg35-37VagCult, PCR2002211Low-risk
RectCult, PCR20073.5Low-risk
Sahraee (67)Rasht2017-2018NAPreg35-37VagCult, PCR245197.8Moderate-risk
Abdollahi Fard (68)Tabriz200622.96 ± 3.89 (mean)Preg35-37Vag, RectCult250249.6Moderate-risk
Akbarian Rad (69)Babol2012-201425.7 ± 5.55 (mean)Preg> 26Vag, RectCult4104611.2Moderate-risk
Shahbazian (70)Ahvaz2007NAPreg35-37Vag, RectCult2503313.2High-risk
Sarafrazi (71)Kashan2000NAPreg35-37VagCult400325.8High-risk

Abbreviations: Cult, culture; GBS, Group B Streptococcus; NA, not available; Preg, pregnant; Rect, rectal; Rect-Vag, rectovaginal; Vag, vaginal.

3.2. Prevalence of Group B Streptococcus in Vaginal and Rectovaginal Swabs of Pregnant Women

The majority of group B Streptococcus research works were based on vaginal or rectovaginal samples. Therefore, an effort was made to analyze and record the data in terms of city, quality assessment index, and year of publication (Tables 1 and 2). The papers were then classified into high-, moderate-, and low-quality index, and consequently, we found vaginal swab samples were in the low-risk (13.7%) group, while rectovaginal cases were in the high-risk (13%) group. Further observation indicated the prevalence of group B Streptococcus from vaginal samples was 15.8% before the year 2000; the city of Sanandaj carried the highest rate with 61.5%, and Tabriz recorded the lowest incidence with 1.8% (Table 2). Data observed from rectovaginal samples (Table 3) revealed that the highest incidence of group B Streptococcus had been observed in 2000 - 2009, during which Isfahan had suffered from the highest rate (18.2%), but Jahrom had the lowest rate (1.7%).

Table 2. Status of Group B Streptococcus Prevalence in Vaginal Samples
SampleNumber of StudiesPrevalence95% CIHeterogeneityP Value
Q- StatisticI-Squared (%)P Value
Experiment date
< 2000215.80.122-0.1940.400.00.528< 0.001
2000 - 20091211.80.076-0.160339.1296.80.000
≥ 20102013.40.096-0.172454.2495.60.000
City< 0.001
Quality assessment< 0.001
Overall3412.90.103-0.155865.9196.10.000< 0.001
Table 3. Status of Group B Streptococcus Prevalence in Rectovaginal Samples
SampleNumber of StudiesPrevalence95% CIHeterogeneityP Value
Q- StatisticI-Squared (%)P Value
Experiment date< 0.001
< 20000---
2000 - 20091011.30.087-0.13949.3981.80.000
≥ 2010158.70.056-0.117286.0095.10.000
City< 0.001
Quality assessment< 0.001
Overall259.70.075-0.120373.4193.60.000< 0.001

4. Discussion and Conclusions

The present systematic review and meta-analysis has summarized 61 published works on group B Streptococcus distribution in Iran. Among 36,807 samples examined, 2,930 samples (9.7%) were reported positive for group B Streptococcus. The prevalence was estimated to be 11.9% in pregnant and 5.3% in non-pregnant women (Table 1). The worldwide investigations show that a total of 11% - 30% of women are carriers of group B Streptococcus in their genital system. The important point is that contaminated women may transfer the bacterium to their fetus or neonates (9, 45, 72).

The knowledge resulting from the present review of group B Streptococcus colonization allows us to conclude that since up to 9.7% of females have been found to be group B Streptococcus-positive, it seems reasonable to suggest a strengthened program for screening the pregnant women to illuminate the more accurate prevalence of group B Streptococcus among the Iranian population. Moreover, a variation was discovered in the reported data, which could be mainly due to different methods for group B Streptococcus detection. Therefore, it is essential to document a more sensitive method for the studies to come. Furthermore, more serious measures are needed to represent an account of group B Streptococcus in infected pregnant women for preventing the transmission of bacterium to their neonates. Additionally, a treatment program must be optimized to eradicate the infection in pregnant women and carriers. Finally, despite controversy in reported data from different populations, group B Streptococcus is surely present in different races around our country. As a result, documenting a legal program is highly recommended for screening pregnant women in rural and low-income populations in this country.


  • 1.

    Imperi M, Pataracchia M, Alfarone G, Baldassarri L, Orefici G, Creti R. A multiplex PCR assay for the direct identification of the capsular type (Ia to IX) of Streptococcus agalactiae. J Microbiol Methods. 2010;80(2):212-4. doi: 10.1016/j.mimet.2009.11.010. [PubMed: 19958797].

  • 2.

    Jannati E, Roshani M, Arzanlou M, 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. [PubMed: 23066487]. [PubMed Central: PMC3465538].

  • 3.

    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):S100-11. doi: 10.1093/cid/cix658. [PubMed: 29117327]. [PubMed Central: PMC5848259].

  • 4.

    Baker CJ. The spectrum of perinatal group B streptococcal disease. Vaccine. 2013;31 Suppl 4:D3-6. doi: 10.1016/j.vaccine.2013.02.030. [PubMed: 23973344].

  • 5.

    Lindahl G, Stalhammar-Carlemalm M, Areschoug T. Surface proteins of Streptococcus agalactiae and related proteins in other bacterial pathogens. Clin Microbiol Rev. 2005;18(1):102-27. doi: 10.1128/CMR.18.1.102-127.2005. [PubMed: 15653821]. [PubMed Central: PMC544178].

  • 6.

    Clouse K, Shehabi A, Suleimat AM, Faouri S, Khuri-Bulos N, Al Jammal A, et al. High prevalence of Group B Streptococcus colonization among pregnant women in Amman, Jordan. BMC Pregnancy Childbirth. 2019;19(1):177. doi: 10.1186/s12884-019-2317-4. [PubMed: 31109301]. [PubMed Central: PMC6528311].

  • 7.

    Emaneini M, Jabalameli F, van Leeuwen WB, Beigverdi R. Prevalence of group B Streptococcus in pregnant women in Iran: a systematic review and meta-analysis. Pediatr Infect Dis J. 2018;37(2):186-90. doi: 10.1097/INF.0000000000001713. [PubMed: 28767617].

  • 8.

    Madzivhandila M, Adrian PV, Cutland CL, Kuwanda L, Schrag SJ, Madhi SA. Serotype distribution and invasive potential of group B streptococcus isolates causing disease in infants and colonizing maternal-newborn dyads. PLoS One. 2011;6(3). e17861. doi: 10.1371/journal.pone.0017861. [PubMed: 21445302]. [PubMed Central: PMC3061872].

  • 9.

    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. doi: 10.5812/jjm.30412. [PubMed: 27127592]. [PubMed Central: PMC4842249].

  • 10.

    Najarian N, Khalili MB, Astani A, Vakili M, Sadeh M. Serotype determination of Streptococcus agalactiae detected from vagina and urine of pregnant women in Yazd, Iran-2015. Int J Med Lab. 2018;5(1):49-57.

  • 11.

    Hansen SM, Uldbjerg N, Kilian M, Sorensen UB. Dynamics of Streptococcus agalactiae colonization in women during and after pregnancy and in their infants. J Clin Microbiol. 2004;42(1):83-9. doi: 10.1128/jcm.42.1.83-89.2004. [PubMed: 14715736]. [PubMed Central: PMC321715].

  • 12.

    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. Lancet Infect Dis. 2016;16(9):1076-84. doi: 10.1016/S1473-3099(16)30055-X. [PubMed: 27236858].

  • 13.

    Nahaei MR, Ghandchilar N, Bilan N, Ghahramani P. Maternal carriage and neonatal colonization of Streptococcus agalactiae in Tabriz, Northwest Iran. Iran J Med Sci. 2007;32(3):177-81.

  • 14.

    Hoy D, Brooks P, Woolf A, Blyth F, March L, Bain C, et al. Assessing risk of bias in prevalence studies: modification of an existing tool and evidence of interrater agreement. J Clin Epidemiol. 2012;65(9):934-9. doi: 10.1016/j.jclinepi.2011.11.014. [PubMed: 22742910].

  • 15.

    Aalei B, Nakhaei N, Davazdah EZ, Mahdizadeh A. The association of preterm labor with vaginal colonization of group B streptococci. Int J Reprod Biomed. 2007;5(4):191-4.

  • 16.

    Absalan M, Eslami G, Zandi H, Mosaddegh A, Vakili M, Khalili MB. Prevalence of recto-vaginal colonization of group B Streptococcus in pregnant women. J Isfahan Med Sch. 2013;30(220).

  • 17.

    Ahmadi A, Farhadifar F, Rezaii M, Zandvakili F, Seyedoshohadaei F, Zarei M, et al. Group B Streptococci and Trichomonas vaginalis infections in pregnant women and those with spontaneous abortion at Sanandaj, Iran. Iran J Microbiol. 2018;10(3):166-70. [PubMed: 30112154]. [PubMed Central: PMC6087698].

  • 18.

    Akhlaghi F, Hamedi A, Naderi NM. Comparison of group B streptococcal colonization in the pregnant diabetic and non-diabetic women. Acta Med Iran. 2009;47(2):103-8.

  • 19.

    Bakhtiari R, Dallal MS, Mehrabadi J, Heidarzadeh S, Pourmand M. Evaluation of culture and PCR methods for diagnosis of group B streptococcus carriage in Iranian pregnant women. Iran J Public Health. 2012;41(3):65-70. [PubMed: 23113150]. [PubMed Central: PMC3481701].

  • 20.

    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. doi: 10.1016/j.jcma.2015.06.021. [PubMed: 26803202].

  • 21.

    Bornasi H, Ghaznavi-Rad E, Fard-Mousavi N, Zand S, Abtahi H. Antibiotic resistance profile and capsular serotyping of Streptococcus agalactiae isolated from pregnant women between 35 to 37 weeks of pregnancy. Koomesh. 2016;17(2).

  • 22.

    Dallal MS, Bakhtiari R, Yazdi JZ, Fallah J, Pourmand M, Yazdchi SB, et al. Carriage of group B streptococcus in pregnant women from Tehran, Iran: P1716. Clin Microbiol Infect. 2008;14. S498.

  • 23.

    Darabi R, Tadi S, Mohit M, Sadeghi E, Hatamizadeh G, Kardeh B, et al. The prevalence and risk factors of group B streptococcus colonization in Iranian pregnant women. Electron Physician. 2017;9(5):4399-404. doi: 10.19082/4399. [PubMed: 28713513]. [PubMed Central: PMC5498706].

  • 24.

    Daramroodi AK, Keshavarzi F, Raissi F. The investigation of antibiotic resistance and rapid detection of group B Streptococcus (Bca) from vaginal specimens of pregnant women by colony PCR method. J Basic Res Med Sci. 2018;5(2):27-32. doi: 10.29252/jbrms.5.2.27.

  • 25.

    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 Med Iran. 2009;47(1):25-30.

  • 26.

    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.

  • 27.

    Frouhesh-Tehrani H, Ashrafi-Hafez A, Sharifi Z, Farahzadi H. Assessment of clindamycin and erythromycin resistance, and inducible clindamycin resistance in Streptococcus group B isolated from urinary samples of outpatient women in Tehran. Nov Biomed. 2015;3(2):79-83.

  • 28.

    Ghanbarzadeh N, Mehramiz M, Gannadkafi M, Namaei MH. The prevalence of group B Streptococcus rectovaginal colonization and antimicrobial susceptibility pattern among pregnant women: A descriptive-analytical study. Modern Care J. 2017;14(3). doi: 10.5812/modernc.66391.

  • 29.

    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. Glob J Health Sci. 2015;7(6):233-9. doi: 10.5539/gjhs.v7n6p233. [PubMed: 26153188]. [PubMed Central: PMC4803879].

  • 30.

    Habibzadeh S, Arzanlou M, Jannati E, Asmar M, Azari M, Fardiazar Z. Maternal carriage of Group B Streptococcus in Ardabil, prevalence and antimicrobial resistance. J Ardabil Univ Med Sci. 2010;10(1):14-20.

  • 31.

    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. [PubMed: 26351472]. [PubMed Central: PMC4539761].

  • 32.

    Hamedi A, Akhlaghi F, Seyedi SJ, Kharazmi A. Evaluation of group B Streptococci colonization rate in pregnant women and their newborn. Acta Med Iran. 2012;50(12):805-8. [PubMed: 23456521].

  • 33.

    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. doi: 10.1159/000323754. [PubMed: 21455000].

  • 34.

    Javadi A, Khourvash F, Tabibian A, Darvishi M, Narimani T. Vaginal and anorectal carriage of group B streptococci in late pregnancy. J Isfahan Med Sch. 2005;22(74-75):89-94.

  • 35.

    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 Islam Repub Iran. 2013;27(1):7-11. [PubMed: 23483827]. [PubMed Central: PMC3592944].

  • 36.

    Kabiri S, Kargar-Jahromi Z, Solhjoo K, Sadeghi-Jahromi S. Frequency of Group B Streptococcus colonization in pregnant women in Jahrom, 2014. Pars Jahrom Univ Med Sci. 2016;14(1):19-26. doi: 10.29252/jmj.14.1.19.

  • 37.

    Kalantar E. High burden of Group B Streptococcus: an invasive bacterium among pregnant women referring to Health Centers of Sanandaj, Iran. Infec Epidemiol Microbiol. 2013;1(1):15-8.

  • 38.

    Kasraeian M, Asadi N, Ghaffarpasand F. Prevalence of asymptomatic bacteriuria among pregnant women in Shiraz, Iran. Saudi Med J. 2009;30(7):917-20. [PubMed: 19618007].

  • 39.

    Khoshkhoutabar T, Zand S, Abtahi H, Rafiei M. Frequency and drug resistance of Group B Streptococcus in pregnant women in Markazi Province, Iran. Med Lab J. 2015;8(4):75-80.

  • 40.

    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. [PubMed: 26989743]. [PubMed Central: PMC4757047].

  • 41.

    Mansouri S, Ghasami E, Najad N. Vaginal colonization of group B Streptococci during late pregnancy in southeast of Iran: incidence, serotype distribution and susceptibility to antibiotics. J Med Sci. 2008;8(6):574-8. doi: 10.3923/jms.2008.574.578.

  • 42.

    Yousefi Mashouf R, Mousavi SM, Rabiee S, Alikhani MY, Arabestani MR. Direct identification of Streptococcus agalactiae at vaginal colonization in pregnant women by PCR. Iran J Public Health. 2014;43(2):69.

  • 43.

    Mobasheri M, Saeedi Varnamkhast N, Karimi A, Banaeiyan S. Prevalence study of genital tract infections in pregnant women referred to health centers in Iran. Turk J Med Sci. 2014;44(2):232-6. doi: 10.3906/sag-1208-33. [PubMed: 25536729].

  • 44.

    Nakhaei Mo M. Recto-vaginal colonization of group B Streptococcus in pregnant women referred to a hospital in Iran and its effect on Lactobacillus normal flora. J Biol Sci. 2010;10(2):166-9. doi: 10.3923/jbs.2010.166.169.

  • 45.

    Mohamadi J, Pakzad I, Khodai Z, Havasian MR. The prevalence of vaginal carrier of group B Streptococcal (GBS) among pregnant women attending maternity at Mustafa-Khomeini Hospital, Ilam. J Exp Biol Agric Sci. 2017;(Spl-1- SAFSAW):561-7. doi: 10.18006/2017.5(4).561.567.

  • 46.

    Mousavi SM, Hosseini SM, Mashouf RY, Arabestani MR. Identification of group B Streptococci using 16S rRNA, cfb, scpB, and atr Genes in pregnant women by PCR. Acta Med Iran. 2016;54(12):765-70. [PubMed: 28120587].

  • 47.

    Saghafi N, Pourali L, Ghazvini K, Maleki A, Ghavidel M, Karbalaeizadeh Babaki M. Cervical bacterial colonization in women with preterm premature rupture of membrane and pregnancy outcomes: A cohort study. Int J Reprod Biomed. 2018;16(5):341-8. [PubMed: 30027150]. [PubMed Central: PMC6046208].

  • 48.

    Namavar Jahromi B, Poorarian S, Poorbarfehee S. The prevalence and adverse effects of group B streptococcal colonization during pregnancy. Arch Iran Med. 2008;11(6):654-7. [PubMed: 18976037].

  • 49.

    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. [PubMed: 24639726]. [PubMed Central: PMC3941399].

  • 50.

    Nazari A, Khalili MB, Astani A, Vakili M, Sadeh M, Mojibiyan M, et al. Determination of genotypes of Streptococcus agalactiae isolated from both urine and vagina of pregnant women referred to gynecology clinics of Yazd, Iran-2015. Int J Med Lab. 2017;4(3):180-8.

  • 51.

    Nazer MR, Rafiei Alavi E, 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.

  • 52.

    Pirooz T, Farsi S, Foroohesh Tehrani H. Group B Streptococci colonization in pregnant women in labor. Razi J Med Sci. 2000;6(4):275-80.

  • 53.

    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.

  • 54.

    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.

  • 55.

    Seyyed EZ, Toossi E, Jalalvand A, Sajadi M. Group B Streptococci investigation in pre-term labors. Med Arch. 2013;67(2):124-5. doi: 10.5455/medarh.2013.67.124-125. [PubMed: 24341060].

  • 56.

    Sharifi Yazdi M, Bakhtiari R, Mobasseri G, Soltan Dallal M, Khalili MB. Study of molecular epidemiologic of Group B Streptococcus colonization in pregnant women by PCR method. J Payavard Salamat. 2011;5(2):51-60.

  • 57.

    Shirazi M, Abbariki E, Hafizi A, Shahbazi F, Bandari M, Dastgerdy E. The prevalence of group B Streptococcus colonization in Iranian pregnant women and its subsequent outcome. Int J Fertil Steril. 2014;7(4):267-70. [PubMed: 24520495]. [PubMed Central: PMC3901181].

  • 58.

    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;13:420. doi: 10.1186/1471-2334-13-420. [PubMed: 24010831]. [PubMed Central: PMC3846163].

  • 59.

    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. Med J Mashhad Univ Med Sci. 2014;57(5):676-83.

  • 60.

    Zamanzad B. Prevalence of group B Streptococcal vaginal carriers in pregnant women referred to the maternity ward of Shahrekord hospital (Year 2000). J Shahid Sadoughi Univ Med Sci. 2000;3:27-31.

  • 61.

    Amirmozafari N, Mansour Ghanaei M, Sadr Nouri B, Farhadi Tooli L. Survey prevalence of group B Streptococci in genital tract women in 28-37 weeks pregnancy. J Guilan Univ Med Sci. 2006;15(59):91-6.

  • 62.

    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.

  • 63.

    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. Pajoohandeh J. 2011;16(3):139-43.

  • 64.

    Khataie G, Shahrokhi N. Bacteriologic and serologic diagnosis of group B streptococci in pregnant women, neonates and infants. Tehran Univ Med J. 1998;56(6):54-60.

  • 65.

    Nasrollahi M, Moghadaszadeh M, Abdollahi M, Marzhoseyni Z, Salehian M, Nazar E, et al. Comparison of culture and PCR methods for diagnosis of group B Streptococcus in women. Curr Sci. 2018;114(8):1738. doi: 10.18520/cs/v114/i08/1738-1741.

  • 66.

    Rostami S, Rahim Khorasani M, Ahmadi M, Naghshineh E, Zamanpour M. Evaluating of molecular diagnostic accuracy of pregnant women colonization with Group B Streptococcus after bacterial enrichment culture. Iran J Obstetr Gynecol Infertil. 2019;21(12):16-22.

  • 67.

    Sahraee S, Milani F, Roushan ZA, Rostami S, Shoja S, Sheikhi R. The prevalence of recto vaginal colonization and antibiotic susceptibility pattern of Streptococcus agalactiae in pregnant women in Al-Zahra Hospital, Rasht, Iran. Infect Dis Clin Prac. 2019;27(3):143-7.

  • 68.

    Abdollahi-Fard S, Ghotasloo R, Zafardoost S. Study on colonization of group В Streptococcus (GBS) and relationship with perinatal complication in pregnant women referred to Alzahra Hospital. Int J Obstetr Gynaecol. 2008;3(7):726-8.

  • 69.

    Akbarian Rad Z, Haghshenas Mojaveri M, Esmaeilzadeh S, Firouzjahi A, Laegh M, Khafri S, et al. Colonization of rectovaginal Escherichia coli and group B streptococci in mothers and on infants' body surface and their related risk factors. Caspian J Pediatr. 2016;2(2):148-52.

  • 70.

    Shahbazian N, Rajabzadeh A, Alavi SM. Prevalence of group-bstreptococcal colonization in vagina and rectum of 35-37 weeks pregnant women and its sensitivity to antibiotics. Jundishapur J Microbiol. 2007;6(3):294-8.

  • 71.

    Sarafrazi N, Mesdaghinia E, Moniri R, Mousavi SGA. Evaluation of vaginal Streptococcus hemolytic type B in pregnant women and its relationship with early neonatal infection. Feyz. 2001;5(2):22-7.

  • 72.

    Fatemi F, Pakzad P, Zeraati H, Talebi S, Asgari S, Chamani TL. Comparative molecular and microbiologic diagnosis of vaginal colonization by group b streptococcus in pregnant women during Labor. Iran J Basic Med Sci. 2010.

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