Multilocus Sequence Typing (MLST) and Phylogenetic Analysis of Group B Streptococcus Isolates from Different Malaysian Hospitals

Abd Aziz, Nur Aimi Liyana (2021) Multilocus Sequence Typing (MLST) and Phylogenetic Analysis of Group B Streptococcus Isolates from Different Malaysian Hospitals. [Project Paper] (Submitted)

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Abstract

Introduction: Group B streptococcus (GBS) or also known as Streptococcus agalactiae is a normal flora that can be found in gastrointestinal and genitourinary tracts of healthy adults. However, invasive disease attributable to infection with GBS results in increasing incidence with a large variety of clinical diseases among newborn children, pregnant women and healthy adults. In Malaysia, literature research on GBS infections in human identified a low number of articles with regard to its serotypes distribution, sequence types (STs) and phylogenetic analysis. Objective: Therefore, this study aims to determine the serotypes distribution, sequence types (STs) and phylogenetic tree of GBS isolated from different hospitals origin in Malaysia in relation to the infected subjects. Methodology: A total of 40 GBS isolates were collected from 5 hospitals in Malaysia. The isolates were characterized on its strains by capsular serotyping using multiplex PCR, while the locus of seven housekeeping genes are characterized by using monoplex PCR. In addition, GBS isolates were analysed by multilocus sequence typing (MLST) to find the sequence type (ST) prior constructing the phylogenetic tree using Mega software to analyse the genetic relationship. Results: The most common serotype was III (n = 11), followed by VI (n = 7), Ia, Ib, II, V (n = 4 each), VII (n = 3), IV (n = 2), and IX (n = 1). The seven housekeeping genes were effectively amplified in 38 GBS isolates, while only six were identified in the other two isolates. MLST analysis revealed 15 different allelic profiles and STs. On the list of 15 STs, ST1 was the most common (n = 13), followed by ST17 (n = 5) and ST283 (n = 2). The sequences of seven housekeeping genes of each isolates were aligned and phylogenetically compared to 15 MLST reference sequences. There are two big branches with Clade I and II that mainly composed of the most isolates which are 25 and 6 respectively in the first branch. On the second branch that consisting of Clade III and IV, each of the clade has 2 and 5 isolates respectively. They were classified based on their resemblance to the isolates studied. Discussion: There is a variation in the serotypes distribution and sequence types (STs) by looking at the patterns in constructed phylogenetic tree of GBS strains that isolates from different Malaysian hospitals. The genotypic distribution patterns and MLST analysis on GBS in this research were mostly consistent with earlier findings from other countries. Conclusion: This implies that some specific genotypes tend to predominate in human infection settings. Therefore, for epidemiological research and vaccine development in Malaysia, further monitoring of GBS from different geographical regions is necessary.

Item Type:	Project Paper
Faculty:	Faculty of Medicine and Health Science
Depositing User:	Ms. Nor Safa'aton Saidin
Date Deposited:	22 Aug 2023 07:06
Last Modified:	22 Aug 2023 07:06
URI:	http://psaspb.upm.edu.my/id/eprint/1000

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