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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. [PMID: 33446117 PMCID: PMC7807883 DOI: 10.1186/s12879-020-05603-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Accepted: 11/09/2020] [Indexed: 01/31/2023] Open
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.
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Affiliation(s)
- Fernando J Bobadilla
- Facultad de Ciencias Exactas, Químicas y Naturales (FCEQyN), Departamento de Microbiología, Universidad Nacional de Misiones (UNaM), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Posadas, Argentina. .,Facultad de Ciencias Exactas, Químicas y Naturales (FCEQyN), Instituto de Biotecnología de Misiones (InBioMis), Universidad Nacional de Misiones (UNaM), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Posadas, Argentina.
| | - Marina G Novosak
- Facultad de Ciencias Exactas, Químicas y Naturales (FCEQyN), Departamento de Microbiología, Universidad Nacional de Misiones (UNaM), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Posadas, Argentina.,Facultad de Ciencias Exactas, Químicas y Naturales (FCEQyN), Instituto de Biotecnología de Misiones (InBioMis), Universidad Nacional de Misiones (UNaM), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Posadas, Argentina
| | - Iliana J Cortese
- Facultad de Ciencias Exactas, Químicas y Naturales (FCEQyN), Instituto de Biotecnología de Misiones (InBioMis), Universidad Nacional de Misiones (UNaM), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Posadas, Argentina
| | - Osvaldo D Delgado
- Facultad de Ciencias Exactas y Naturales (FACEN), Universidad Nacional de Catamarca (UNCa), Centro de Investigación y Transferencia Catamarca (CITCA-CONICET), San Fernando del Valle de Catamarca, Argentina
| | - Margarita E Laczeski
- Facultad de Ciencias Exactas, Químicas y Naturales (FCEQyN), Departamento de Microbiología, Universidad Nacional de Misiones (UNaM), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Posadas, Argentina.,Facultad de Ciencias Exactas, Químicas y Naturales (FCEQyN), Instituto de Biotecnología de Misiones (InBioMis), Universidad Nacional de Misiones (UNaM), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Posadas, Argentina
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