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

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.