Abstract
Abstract
Background
In pregnant women Streptococcus agalactiae (GBS) can be transmitted to newborn causing severe infections. It is classified into 10 serotypes (Ia, Ib, II-IX). The severity of neonatal disease is determined by the capsular serotype and virulence factors such as the polysaccharide capsule, encoded by the cps gene, protein C, which includes the Cα surface proteins (bca gene), Rib (rib gene) and Cβ (bac gene); the proteins Lmb (lmb gene), FbsB (fbsB gene), FbsA (fbsA gene), the cyl operon encoding a β-hemolysin (hylB gene), the CAMP factor (cfb gene) and the C5a peptidase (scpB gene). The aim of this work was to determine the degree of GBS colonization in pregnant women, the serotypes distribution and to investigate virulence-associated genes.
Methods
We worked with 3480 samples of vagino-rectal swabs of women with 35–37 weeks of gestation. The identification of the strains was carried out using conventional biochemical tests and group confirmatory serology using a commercial latex particle agglutination kit. Two hundred GBS strains were selected. Their serotype was determined by agglutination tests. The monoplex PCR technique was used to investigate nine virulence-associated genes (cps, bca, rib, bac, lmb, fbsB, fbsA, hylB and scpB).
Results
The maternal colonization was 9.09%. The serotypes found were: Ia (33.50%), III (19.00%), Ib (15.50%), II (14.00%), V (7.00%) and IX (5.50%). 5.50% of strains were found to be non-serotypeable (NT). The nine virulence genes investigated were detected simultaneously in 36.50% of the strains. The genes that were most frequently detected were scpB (100.00%), fbsA (100.00%), fbsB (100.00%), cylB (95.00%), lmb (94.00%) and bca (87.50%). We found associations between serotype and genes bac (p = 0.003), cylB (p = 0.02), rib (p = 0.01) and lmb (p < 0.001).
Conclusions
The frequency of vaginal-rectal colonization, serotypes distribution and associated virulence genes, varies widely among geographical areas. Therefore, epidemiological surveillance is necessary to provide data to guide decision-making and planning of prevention and control strategies.
Publisher
Springer Science and Business Media LLC
Reference62 articles.
1. Jackson L, Hilsdon R, Farley M, Harrison L, Reingold A, Plikaytis B, et al. Risk factors for group B streptococcal disease in adults. Ann Intern Med. 1995;123(6):415–20. https://doi.org/10.7326/0003-4819-123-6-199509150-00003.
2. Centers for Disease Control and Prevention (CDC). Perinatal group B streptococcal disease after universal screening recommendations-United States, 2003–2005. MMWR Morb Mortal Wkly Rep. 2007;56(28):701–5.
3. ARGENTINA, HONORABLE CONGRESO DE LA NACION. Ley Nacional 26.369. [on line] https://www.argentina.gob.ar/normativa/nacional/ley-26369-140274/texto.
4. Misiones., Cámara de Representantes de la Provincia de. Digesto Jurídico. [on line] 2007. http://digestomisiones.gob.ar/buscador?page=92.
5. Tudela C, Stewart R, Roberts S, Wendel G, Stafford I, McIntire D, Sheffield J. Intrapartum evidence of early-onset group B streptococcus. Obstet Gynecol. 2012;119(3):626–9. https://doi.org/10.1097/AOG.0b013e31824532f6.