1. Background

Streptococcus agalactiae (S. agalactiae), also known as group B Streptococcus (GBS) is a commensal bacteria of human intestine and genital tract. It can intermittently colonialize the vaginal cavity and women’s bladder. Infections with group B streptococcus in women are mild (urinary infections). However, this bacterium could be responsible for serious infections in pregnant women, foetuses and the newborns. The first cases of GBS neonatal infections have been reported by Eickhoff ^[1]. Group B Streptococcus infection represents a major cause of neonatal mortality and morbidity ^[2]. The public health burden of these infections on newborns as well as on women is important. That is mainly, neurological sequelae for the newborn and maternal sterility following postpartum endometritis. Because of its frequency and complications, GBS foetomaternal infection remains a major concern for perinatal care professionals. Its (GBS) mother-to-child transmission depends on the presence of the bacteria during the pregnancy ^{[2, 3, 4]}. The prevalence of vaginal colonization by GBS among women varies across the world: 19% - 35% in North America, 20% in Africa and 8% - 15% in Europe. The frequency of vertical mother-to-child transmission ranges from 40 to 70% ^[4].

Confronted with the importance of maternal colonization and the pathogenic power potential of this bacterium, screening, prevention and treatment strategies have been developed. The goal was to identify the GBS carrying patients at the third trimester of pregnancy and offer them an antibiotherapy, the only effective mean to prevent neonatal infections ^[5].

In Togo, there is no national guideline for systematic screening of GBS in pregnant women receiving for prenatal care. The objective of this study was to measure the prevalence of GBS genital carriage among pregnant women in Lomé, and to treat the bacteria carrying – patients.

2. Materials and Methods

Design of the study. Our study took place in the Sylvanus Olympio University Hospital (CHU-SO), Service of Obstetrics – Gynecology and Microbiology Laboratory Service.

We conducted a cross-sectional study during the period of March 2012 through Mai 2012. We included all pregnant women received for their third trimester consultation and who had a gestational age ranging from 34 to 38 weeks of amenorrhea.

Samples have been collected in a prenatal consultation room and have been processed in the microbiology laboratory of the hospital.

Laboratory method. In the laboratory, vaginal swabs were seeded in petri dishes containing sheep blood agar and incubated at 37°C during 24 hours. The serogrouping has been performed on suspected bacteria colonies after incubation. This serogrouping consisted of a latex particles agglutination test for the identification of streptococcus groups A, B, C, D, E, F and G according to the Lancefield classification ^{[6, 7]}. The streptococcal extracts were prepared using the method set-up by Maxted ^[8]. The reaction was considered positive when agglutination appeared with one of the reagents or when agglutination was more important with one of the reagents than the five others. When no agglutination appeared, the reaction was considered negative.

We performed the antibiogram by using the agar diffusion assay also known as disc diffusion method, which consisted in dropping antibiotic discs on an agar media previously inoculated with an isolated GBS strain. Petri dishes are incubated between 35 and 37°C for 16 to 18h. Once the incubation completed, the diameters of inhibition areas were measured. The reading and interpretation of the antibiogram was performed according to The French Society of Microbiology guidelines ^[9].

Statistical analysis. We collected and analyzed the following variables: age, gestational age, education level, marital status, religion and pregnancy, medical, gyneco-obstetric and chirurgical history.

Table 1. Distribution of women according to marital status, religion and education level

Download as

PowerPoint Slide

Larger image(png format)

Tables index

Veiw figure

View current table in a new window

View next table

3. Results

During the study, 200 pregnant women were screened, at a minimum, maximum and average age of 19, 40 and 28 years old respectively. Most of the women were married (88%) and christian (85%). With reference to the level of education, the percentage was 12.5%, 30.5%, 49% and 8% corresponding to uneducated, primary, secondary and university level respectively (Table 1). Upon bacteriological assay completion, five (5) strains of GBS have been isolated from 5 pregnant women, representing a bacterial carriage rate of 2.5% (5/200), 95% CI (0.3-4.7). The sociodemographic characteristics of GBS carriers (women) were shown on (Table 2). Any risk factor associated with the carriage was identified. The GBS strains isolated were susceptible to penicillin G, erythromycin, co-amoxiclav and levofloxacin (Table 3). The five GBS carriers delivered by cesarean section for various reasons (Table 4).

Table 2. Sociodemographic characteristics of GBS carriers (women)

Download as

PowerPoint Slide

Larger image(png format)

Tables index

Veiw figure

View current table in a new window

View previous table

View next table

Table 3. Reasons of cesarean among the GBS carriers

Download as

PowerPoint Slide

Larger image(png format)

Tables index

Veiw figure

View current table in a new window

View previous table

View next table

Table 4. Characteristics of antibiotics tested on GBS strains isolated

Download as

PowerPoint Slide

Larger image(png format)

Tables index

Veiw figure

View current table in a new window

View previous table

4. Discussions

The GBS vaginal carriage is intermittent and transitory. The Centers for Disease Control and Prevention (CDC) recommends a screening between the 35^thand 37^thweeks of amenorrhea ^[10]; and the French “Agence Nationale d'Accréditation et d'Evaluation en Santé (ANAES)”, recommends a screening at the 34^th and the 38^th week of amenorrhea ^[11]. The vaginal colonization by GBS is estimated around 10 to 20% across the world. However this rate varies in great proportions according to the country, the study population, testing sites, the testing period, and the technic for bacterial isolation used ^[4].

In our study, we estimated the GBS vaginal carriage between the 34^th and the 38^th week of amenorrhea. We found a rate of 2.5%, which represents a low carriage. This rate is close to the 3.7% found in 1991 in the same Hospital of Lomé renamed nowadays Centre Hosptalier et Universitaire Sylvanus Olympio ^[12]. However, our finding is very low as compared to those reported in others African countries such as Nigeria (6.6-17.6%) [13-18]^[13], Côte d’Ivoire. (7.30-19%) ^{[4, 19]}; Gambia (22%) ^[20], Zimbabwe (20-30%) ^[21], Malawi (16,5%) ^[22]. Tunisia (13%) ^[23]. In European countries, the prevalence of rectovaginal colonization varies from 6.5 to 36% ^[24]. Studies carried out in United Kingdom ^[25] and in Belgium ^[26] reported respectively 21.3% and 22%, data are higher than the carriage rate in this study. The prevalence of GBS carriage found in our study, remains low compared to data from India (16%) ^[27], south east Asia (12%) ^[28], Iran (6%) ^[29] Brazil (15,6%) ^[30] and USA(12.2%) ^[31]. Single vaginal culture and lack of rectal culture can partly explain the low prevalence in our study. Higher prevalence rates have been reported in studies that involved rectovaginal sample collections and also women with preterm rupture of membranes ^[32]. Although, this may not be a limitation of this study, one recent study showed that perianal and rectal cultures yield similar results ^[33]. There are various bacteriologic techniques for GBS identification. The low prevalence showed in this study can be also related to our culture methods for detection of group B streptococcus carriage in pregnant women ^[34]. The colonization rate by culture is low when compared with antigen detection method and PCR. Although we cannot rule out the possibility of detection of non viable GBS by antigen detection and PCR assays, several conditions can explain the false negative culture results. These include antibiotics, feminine hygiene products and scanty colonization, which would be difficult to obtain in culture ^{[35, 36]}. Besides being time consuming, culture requires an experienced technician to identify the suspected colonies, which are not always beta-hemolytic ^[37] and effect of storage conditions can impact sensitivity and specificity GBS culture methods because detection of GBS by culture requires viable organisms ^[38].

Our sample size is small and we found a low GBS carriage rate. This fact does not give us the possibility to draw any conclusion regarding the characteristics (sociodemographic and medical) of the bacteria carriers and the antibiogram profile of GBS isolates

5. Conclusion

Through this research activity, we have been able to estimate the prevalence of GBS carriage among women at the last stage of pregnancy receiving prenatal care at the CHU-SO, Lomé. We found a carriage rate of 2.5%. In the settings of maternal and foetal infection by this bacterium, the greatest concern is to identify the quickest and most reliable diagnostic technique. Neonatal infection is a therapeutic emergency and the severe outcome resulting in neonatal meningitis justifies the need to screen the GBS vaginal carriage at the last stage of pregnancy and a preventive treatment in case of vaginal colonization by the bacteria.

Conflict of Interest

All authors declare that none of them have any conflict of interest

Acknowledgment

We thank all the women who participated to the study. We thank the CHU SO Gynecology staff and the Microbiology laboratory Staff especially Mr. Tigossou Segla for his help. We also thank M. KAO Kpatcha who bought the latex particles agglutination test and the Petri dishes.

References

[1]	Eickhoff TC, Klein, JO, Daly AK et al Neonatal sepsis and other infections due to group B beta-hemolytic streptococci. New England Journal of Medicine, 1964: 271(24): 1221-1228.
	In article		CrossRef
[2]	Krohn MA, Sharon L. Hillier, Carol JB Maternal peripartum complications associated with vaginal group B streptococci colonization. Journal of Infectious Diseases.1999, 179(6): 1410-1415.
	In article		CrossRef
[3]	Regan JA, Klebanoff M A., Nugent RP et al. Colonization with group B streptococci in pregnancy and adverse outcome. American journal of obstetrics and gynecology. 1996, 174 (4): 1354-1360.
	In article		CrossRef
[4]	Stoll BJ and Schuchat A Maternal carriage of group B streptococci in developing countries. Pediatric infectious disease journal.1998, 17(6): 499-503.
	In article		CrossRef
[5]	Schrag S, Gorwitz R, Fultz-Butts K, Schuchat, A. Prevention of perinatal group B streptococcal disease MMWR Recomm Rep51.2002, (11): 1-22.
	In article
[6]	Lancefield, Rebecca C. A serological differentiation of specific types of bovine hemolytic streptococci (group B). J Exp Med 1934;(59): 441-448.
	In article		CrossRef
[7]	Baker CJ, Clark DJ, Barrett FF Selective broth medium for isolation of group B streptococci. Applied microbiology. 1973, 26(6): 884-885.
	In article
[8]	Maxted, Wr R. Preparation of streptococcal extracts for Lancefield grouping. The Lancet. 1948, 252(6520): 255-256.
	In article		CrossRef
[9]	Bonnet R, Cavallo JD, Chardon H et al. Comité de l'antibiogramme de la Société Française de Microbiologie.2012, Recommandations 2011. Société Française de Microbiologie.
	In article
[10]	Verani, Jennifer R., Lesley McGee, and Stephanie J. Schrag Prevention of perinatal group B streptococcal disease. Morbidity and Mortality Weekly Report (MMWR), Revised Guidelines from CDC, Recommendations and Reports 59.RR10 (2010): 1-32.
	In article
[11]	ANAES : Prévention anténatale du risque infectieux bactérien néonatal précoce. ANAES, Service Recommandations et Références Professionnelles. Septembre 2001. IBSN 2-910653-00-0.
	In article
[12]	David-Prince M, Ategbo S, De Souza A E, Eklu-Avlassu EK, Grunitzky-Bekele M, Schmidt-Ehry G, Hodonou K, et. Assimadi K. Portage du streptocoque B dans le couple mère-enfant à la naissance: a propos de 106 cas. Bulletin de la Société de pathologie exotique. 1991, 84(5-5BIS): 522-531.
	In article
[13]	Nsagha, D.S.; Bello, C.S.S. and Kahdakai- Olukemi, V.T. Maternal Carriage in Pregnancy of Group B Streptococcs in Jos: Relation of Endocervical Anorectal Colonization. Nig. Qt. J. Hosp. Med. 1997, 7: 53-56.
	In article
[14]	Nwachukwu, N.C.; Utsalo, S. J.; Kanu, I. and Anyanwu, E.C. Genital Colonization of Group B Streptococcus at Term Pregnancy in Calabar, Nigeria. The Internet Journal of Pediatrics and Neonatology.2007. ISSN: 1528-8374.
	In article
[15]	Onile, B.A. Group B Streptococcus carriage in Nigeria. Trans. Rovy. Sco. Trop. Med. & Hyg. 1980: 74: 367-370. Onile 1980 (13).
	In article
[16]	Uhiara, J.E. Group B Streptococcal carriage among parturient and their neonates in Zaria, Nigeria. Afr. J. Med. 1993 Sci. 22(3): 79-83.
	In article
[17]	Donbraye-Emmanuel, O.O.B.; Okonko, I.D.; Donbraye, E.; Fadeyi, A.; Abubakar, M.J, Adebiyi, O.E. and Fashina, N.A. Isolation and characterization of Group B Steptococci and other pathogens among pregnant women in Ibadan Southwest Nigeria. Journal of Applied Biosciences. 2010, 29: 1781-1792.
	In article
[18]	Onipede A., Adefusi O, Adeyemi A., Adejuyigbe E., Oyelese A., Ogunniyi*T. Group B streptococcus carriage during late pregnancy in ile-ife, Nigeria. Afr. j. cln. exper. microbiol. 2012, 13(3): 135-143.
	In article
[19]	Kacou, A, Faye-kette A H, Sylla-koko FD et al. Distribution des streptocoques dans les produits biologiques analysés à Abidjan de 1982 à 1988. Médecine d'Afrique noire. 1991, 38 (7): 538-540.
	In article
[20]	Suara, RO, Adegbola RA, Baker C J et al. Carriage of group B streptococci in pregnant Gambian mothers and their infants. Journal of Infectious Diseases. 1994, 170(5): 1316-1319.
	In article		CrossRef
[21]	Moyo, S.R.; Modzori, J.; Tswana, S.A.; Mealand, J.A. Prevalence, capsular type distribution, authropometric and obstetric factors of group B Streptococcus (Streptococcus agalactiae) colonization in pregnancy. Central Africa Journal of Medicine. 2000: 40(5): 115-120.
	In article
[22]	Dzowela, T.; Komolafe, O.O. and Igbigbi, A. Prevalence of Group B Streptococcus colonization in antenatal women at the Queen Elizabeth Central Hospital, Blantyre,a preliminary study. Malawi Medical Journal. 2005. 17 (3): 97-99.
	In article
[23]	Ferjani A, Abdallah H B., Saida NB et al. Portage vaginal de Streptococcus agalactiae chez la femme enceinte en Tunisie: facteurs de risque et sensibilité aux antibiotiques des isolats. Bull Soc Pathol Exot. 2006, 99 (2): 99-102.
	In article
[24]	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: 260-271.
	In article		CrossRef
[25]	Jones N, Oliver K., Jones Y et al., Carriage of group B streptococcus in pregnant women from Oxford, UK. Journal of clinical pathology.2006, 59 (4): 363-366.
	In article		CrossRef
[26]	El Aila NA, Tency I, Claeys G, Saerens B, Cool P, Verstraelen H, Temmerman M, Verhelst R, Vaneechoutte M. Comparison of different sampling techniques and of different culture methods for detection of group B streptococcus carriage in pregnant women BMC Infectious Diseases 2010, 10: 285 https://www.biomedcentral.com/1471-2334/10/285.
	In article		CrossRef
[27]	Kavitha PK, Shrikala B, Suchithra S, Bharati B. Evaluation of Culture, Antigen Detection and Polymerase Chain Reaction for Detection of Vaginal Colonization of Group B Streptococcus (GBS) in Pregnant Women Journal of Clinical and Diagnostic Research. 2014 Feb, Vol-8 (2): 47-49.
	In article
[28]	Turner C, Turner P, Po L, Maner N, De Zoysa A, Baharak Afshar, Androulla Efstratiou, Paul T Heath and François Nosten. Group B streptococcal carriage, serotype distribution and antibiotic susceptibilities in pregnant women at the time of delivery in a refugee population on the Thai-Myanmar border turner et al. BMC Infectious Diseases 2012, 12: 34 https://www.biomedcentral.com/1471-2334/12/34.
	In article
[29]	Abdolkarim Hamedi, Farideh Akhlaghi, Seyed Javad Seyedi, and Abdolali Kharazmi. Evaluation of Group B Streptococci Colonization Rate in Pregnant Women and Their Newborn Acta Medica Iranica. 2012: 50, 12.
	In article
[30]	Paulo Cesar Giraldo EdilsonD.Araujo,Jose ́ Eleute ́rio Junior, Rose Luce Gomes do Amaral, Mauro R. L. Passos, and Ana Katherine Gonc ̧alves The Prevalence of Urogenital Infections in Pregnant Women Experiencing Preterm and Full-Term Labor.
	In article
[31]	Infectious Diseases in Obstetrics and Gynecology 2012, Article ID 878241, 4 pages.
	In article
[32]	Chohan, L.; Hollier, L.M.; Bishop, K. and Kilpatrick, C.C. Patterns of antibiotic resistance among group B streptococcus isolates: 2001-2004. Infect. Dis. Obstet. Gynecol. 2006, 57492.
	In article
[33]	Gupta C, Briski LE: Comparison of two culture media and three sampling techniques for sensitive and rapid screening of vaginal colonization by group B streptococcus in pregnant women. J Clin Microbiol 2004, 42(9): 3975-3977.
	In article		CrossRef
[34]	Trappe KL, Shaffer LE, Stempel LE. Vaginal-perianal compared with vaginal-rectal cultures for detecting group B streptococci during pregnancy. Obstet Gynecol. 2011, 8:313-317.
	In article		CrossRef
[35]	El Aila N.A, Tency I, Claeys G, Saerens B, De Backer E, Temmerman M, Verhelst R and Vaneechoutte M. Genotyping of Streptococcus agalactiae (group B Streptococci) isolated from vaginal and rectal swabs of women at 35-37 weeks of pregnancy BMC Infectious Diseases 2009, 9: 153.
	In article		CrossRef
[36]	Rallu F, Barriga P, Scrivo C, Martel – Laferriere V, Laferriere C. Sensitivities of antigen detection and PCR assays greatly increased compared to that of the standard culture method for screening for Group B Streptococcus carriage in pregnant women. J Clin Microbiol. 2006, 44: 725-28.
	In article		CrossRef
[37]	Werneke M, Mullen C, Sharma V, Morrison J, Barry T, Maher M et al. Evaluation of a novel Real-time PCR test based on ssrA gene for the identification of Group B Streptococci in vaginal swabs. BMC Infect Dis. 2009; 9: 148.
	In article		CrossRef
[38]	Winn W, Allen S, Janda W. Koneman’s Color Atlas and Text book of Diagnostic Microbiology. 6th edition. 2006; 683-717.
	In article
[39]	Rachel M. Ostroff and Jeffrey W. Steaffens. Effect of Specimen Storage, Antibiotics, and Feminine Hygiene Products on the Detection of Group B Streptococcus by Culture and the STREP B OIA Test Diagn Microbiol infect dis. 1995, 22: 25-259.
	In article