Genotyping of Clinical Streptococcus agalactiae Strains Based on Molecular Serotype of Capsular (cps) Gene Cluster Sequences Using Polymerase Chain Reaction

Abstract

Background: Group B Streptococcus (GBS) is major cause of serious life threatening infections including sepsis, pneumonia and meningitis in neonates as well as in pregnant women. Capsular polysaccharide typing is significant and essential for epidemiological studies of GBS. Objectives:The aim of the current study was to differentiate genotypes of GBS clinical isolates based on the polymerase chain reaction (PCR) to acquire information about distribution of GBS types in Hamedan, Iran. Methods: In this experimental study we used sixty-two GBS clinical strains isolated from vaginal swabs (n = 16), urine cultures (n = 45) and blood culture (n = 1) of patients, who had referred to educational hospitals and private clinic centers during nine months from June 2013 to February 2014 in Hamedan, Iran, for genotyping using multiplex PCR assay. Results: Among the 62 GBS isolates examined, all capsular types except for VI, VII and VIII were found. Types III and V were the most prevalent types with a sum of 46 isolates (74.2%). Type III was the predominant type with 35 (56.5%) isolates, followed by type V (11 isolates; 17.7%), type II (seven isolates; 11.3%), type Ia (five isolates; 8.1%) and Ib and IV with similar prevalence of two isolates (3.2%). Conclusions:The results of the current study demonstrated that type III is the predominant type in Hamedan, followed by types V, type II, type Ia, Ib and IV, respectively. Use of the molecular serotyping (MS) method such as PCR assay as an alternative to conventional serotyping (CS) method leads to accurate, sensitive, specific, and fast typing of GBS isolates.

Capsular gene distribution and RAPD typing of Streptococcus agalactiae isolated from pregnant women

“…Streptococcus agalactiae is detected as a vaginal and intestinal microbiota in women causing concerning health associated problems in newborns (do Nascimento et al 2019 ; Arabestani et al 2017 ; Khademi and Sahebkar 2020 ). This bacterium is the cause of the early onset disease and late onset disease in neonates delivered by mothers with risk factors, including the delivery before the 37th week of pregnancy, the membrane rupture at least 18 h before delivery, an unexplained fever (≥ 38 °C) during delivery, and a S. agalactiae caused a history of invasive disease in a previous infant or urinary tract infection in the current pregnancy (Genovese et al 2020 ; Khademi and Sahebkar 2020 ).…”

“…S. agalactiae is classified based on capsular polysaccharide antigens, and ten serotypes are currently determined, including Ia, Ib, and II-IX (Botelho et al 2018 ; Haimbodi et al 2021 ; Huang et al 2019 ). Serotypes Ia, II, III, and V are the more prevalent S. agalactiae in USA and Europe, causing human diseases (Arabestani et al 2017 ). Also, serotypes III, Ia, Ib, II, and V are the most prevalent S. agalactiae in neonatal disease, while type III has been associated with severe infections (Arabestani et al 2017 ; Barros et al 2023 ).…”

“…Serotypes Ia, II, III, and V are the more prevalent S. agalactiae in USA and Europe, causing human diseases (Arabestani et al 2017 ). Also, serotypes III, Ia, Ib, II, and V are the most prevalent S. agalactiae in neonatal disease, while type III has been associated with severe infections (Arabestani et al 2017 ; Barros et al 2023 ). On the other hand, according to a meta-analysis of 390 articles, serotypes Ia, Ib, II, III, and V were the most prevalent S. agalactiae serotypes colonizing almost 98% of all pregnant women (Huang et al 2019 ; Alzayer et al 2023 ).…”

“…An Iranian research reported that serotypes III, V, II, and Ib were the most prevalent S. agalactiae isolated from the clinical samples (Emaneini et al 2014 ). The prevalence of different capsular serotypes in various isolates of S. agalactiae is varied in different parts of the world (Arabestani et al 2017 ; Emaneini et al 2014 ; Haimbodi et al 2021 ; Huang et al 2019 ). Because the polysaccharide capsule is one of the most important antigens of this bacterium, determining the capsular serotype seems necessary to determine the suitable candidate for vaccine production in each region (Botelho et al 2018 ; do Nascimento et al 2019 ; Barros et al 2023 ).…”

Molecular Characterization of Streptococcus agalactiae Isolates from Pregnant Women in Kathmandu City

“…Based on the capsular polysaccharide (CPS) antigens, GBS are classified into 13 serotypes. Among 13 variants, 9 variants, Ia, Ib, II, III, IV, V, VI, VII, and VIII, are considered as clinically important [ 6 ]. The capsular polysaccharides of GBS isolates are the important virulence factors with antiphagocytic purposes and therefore are used as the key components of developing new multivalent GBS vaccines [ 4 ].…”