PDF
ePub
Citation
Print
Abstract
Background
The prevalence of neonatal group B streptococcal infection depends mainly on the colonization rate of pregnant women by group B streptococci (GBS). Although the colonization rate of Korean women by GBS is considered lower than in other countries, recent data on the maternal colonization rate of GBS are sparse.
Methods
From August 2008 to June 2009, swab specimens from the anorectus, vagina, and urethral orifice of a sample of 234 pregnant Korean women were placed in new Granada medium (NGM-H), tube medium (NGM-T), commercial NGM (NGM-B), and selective Todd-Hewitt broth (S-THB) for 18∼24 hours in 5% CO2 at 35oC. Agar dilutional antimicrobial susceptibility tests, serotyping, and PCR were performed for GBS isolates.
Results
The colonization rate of GBS in pregnant women was 11.5% (27/234). Of the specimen cultures, 9.8% of anorectal cultures were positive, 8.1% of urethral orifice cultures were positive, and 7.3% of vagina cultures were positive. The detection rate of GBS in the different culture media was S-THB (96.3%), NGM-B (92.6%), NGM-H (88.9%), and NGM-T (85.2%). The distribution of GBS serotypes was as follows: III (29.6%), V and VI (22.2%), Ib and II (11.1%), and Ia (3.7%). 33.3% of GBS isolates were resistant to erythromycin and 44.4% to clindamycin. Among the nine erythromycin-resistant isolates, eight were serotype V and VI, which are erm(B) positive serotypes.
Conclusion
The colonization of pregnant women by GBS, and the incidence of resistance of the GBS isolates to erythromycin and clindamycin were higher than those previously reported. Serotypes V and VI, GBS serotypes that carry the erm(B), are novel serotypes that have not previously been identified in pregnant Korean women.
REFERENCES
1. Boyer KM, Gadzala CA, Burd LI, Fisher DE, Paton JB, Gotoff SP. Selective intrapartum chemoprophylaxis of neonatal group B streptococcal early-onset disease. I. Epidemiologic rationale. J Infect Dis. 1983; 148:795–801.
2. Gray BM, Pass MA, Dillon HC Jr. Laboratory and field evaluation of selective media for isolation of group B streptococci. J Clin Microbiol. 1979; 9:466–70.
3. Pasnick M, Mead PB, Philip AG. Selective maternal culturing to identify group B streptococcal infection. Am J Obstet Gynecol. 1980; 138:480–4.
4. Gjerdingen DK. Premature labor, Part I: Risk assessment, etiologic factors, and diagnosis. J Am Board Fam Pract. 1992; 5:495–509.
5. Wilkinson HW. Group B streptococcal infection in humans. Ann Rev Microbiol. 1978; 32:41–57.
6. Burman LG, Christensen P, Christensen K, Fryklund B, Helgesson AM, Svenningsen NW, et al. Prevention of excess neonatal morbidity associated with group B streptococci by vaginal chlorhexidine disinfection during labour. Lancet. 1992; 340:65–9.
7. Campbell JR, Baker CJ, Edwards MS. Influence of serotype of group B streptococci on C3 degradation. Infect Immun. 1992; 60:4558–62.
8. Uh Y, Jang IH, Hwang GY, Yoon KJ. Antimicrobial resistance and serotypes in the clinical isolates of group B streptococci. Korean J Clin Microbiol. 1999; 2:64–70.
9. Uh Y, Jang IH, Hwang GY, Lee MK, Yoon KJ, Kim HY. Serotypes and genotypes of erythromycin-resistant group B streptococci in Korea. J Clin Microbiol. 2004; 42:3306–8.
10. Uh Y, Kwon JY, Jang IH, Yoon KJ, Kim HG. Colonization rate of group B Streptococcus in pregnant women and neonates. Korean J Clin Pathol. 1994; 14:447–53.
11. Uh Y, Jang IH, Yoon KJ, Lee CH, Kwon JY, Kim MC. Colonization rates and serotypes of group B streptococci isolated from pregnant women in a Korean tertiary hospital. Eur J Clin Microbiol Infect Dis. 1997; 16:753–6.
12. Uh Y, Jang IH, Yoon KJ, Kwon JY. Colonization rate and serotypes of group B streptococci in first trimester of pregnancy. Korean J Clin Pathol. 1998; 18:183–6.
13. Uh Y, Jang IH, Kwon JY, Kim NS, Kim MC, Park DW, et al. Studies on the usefulness of new Granada selective medium for the detection of group B streptococci in pregnant women. J Wonju Med Coll. 1996; 9:7–15.
14. Clinical and Laboratory Standards Institute. Methods for dilution antimicrobial susceptibility tests for bacteria that grow aerobically. 8th ed., Approved standard M07-A8. Clinical and Laboratory Standards Institute, Wayne, PA.,. 2009.
15. CDC. Prevention of perinatal group B streptococcal Disease. MMWR. 2002; 51:1–22.
16. Centers for Disease Control and Prevention (CDC). Laboratory practices for prenatal group B streptococcal screening and reporting-Connecticut, Georgia, and Minnesota, 1997-1998. MMWR Morb Mortal Wkly Rep. 1999; 48:426–8.
17. Dillon HC Jr, Gray E, Pass MA, Gray BM. Anorectal and vaginal carriage of group B streptococci during pregnancy. J Infect Dis. 1982; 145:794–9.
18. Boyer KM, Gadzala CA, Kelly PD, Burd LI, Gotoff SP. Selective intrapartum chemoprophylaxis of neonatal group B streptococcal early-onset disease. II. Predictive value of prenatal cultures. J Infect Dis. 1983; 148:802–9.
19. Lachenauer CS, Kasper DL, Shimada J, Ichiman Y, Ohtsuka H, Kaku M, et al. Serotypes VI and VIII predominate among group B streptococci isolated from pregnant Japanese women. J Infect Dis. 1999; 179:1030–3.
20. Uh Y, Kim HY, Jang IH, Hwang GY, Yoon KJ. Correlation of serotypes and genotypes of macrolide-resistant Streptococcus agalactiae. Yonsei Med J. 2005; 46:480–3.
Table 1.
Colonization incidence of 234 pregnant women by GBS according to specimen type and culture method
Table 2.
Activities of antimicrobial agents against 27 isolates of group B streptococci from pregnant women
Table 3.
Distribution of MLSB gene and serotypes of GBS isolated from pregnant women
| MLSB gene | No. (%) of serotype | Total | |||||
|---|---|---|---|---|---|---|---|
| Ia | Ib | II | III | V | VI | ||
| erm(B) | 0 (0) | 0 (0) | 0 (0) | 0 (0) | 4 (50.0) | 4 (50.0) | 8 |
| mef(A) | 0 (0) | 0 (0) | 0 (0) | 1 (100) | 0 (0) | 0 (0) | 1 |
| ND∗ | 1 (5.6) | 3 (16.7) | 3 (16.7) | 7 (38.9) | 2 (11.1) | 2 (11.1) | 18 |
| Total | 1 (3.7) | 3 (11.1) | 3 (11.1) | 8 (29.6) | 6 (22.2) | 6 (22.2) | 27 |
XML Download