Multi locus sequence typing of Burkholderia pseudomallei isolates from India unveils molecular diversity and confers regional association in Southeast Asia

Abstract

ObjectivesBurkholderia pseudomallei, the causative agent for melioidosis, has become a public health problem in India and across the world. Melioidosis can be difficult to diagnose because of the inconsistent clinical presentations of the disease. This study aims to determine the genetic diversity among the clinical isolates of B. pseudomaelli from India in order to establish a molecular epidemiology and elucidate the Southeast Asian association.MethodsMolecular typing using multi locus sequence typing was performed on thirty one archived B. pseudomallei clinical isolates, previously characterised from specimens obtained from patients admitted to the Christian Medical College & Hospital, Vellore from 2015 to 2016. Further investigations into the genetic heterogeneity and evolution at a regional and global level were performed using insilico tools.ResultsMulti locus sequence typing (MLST) of the isolates from systemic and localized forms of melioidosis, including blood, pus, tissue, and urine specimens, revealed twenty isolates with novel sequence types and eleven with previously reported sequence types. High genetic diversity was observed using MLST with a strong association within the Southeast Asian region.ConclusionsMolecular typing of B. pseudomallei clinical isolates using MLST revealed high genetic diversity and provided a baseline molecular epidemiology of the disease in India with a strong Southeast Asian association of the strains. Future studies should focus on whole genome based Single-Nucleotide-Polymorphism (SNP) which has the advantage of a high discriminatory power, to further understand the novel sequence types reported in this study.

Molecular analysis of clinical Burkholderia pseudomallei isolates from southwestern coastal region of India, using multi-locus sequence typing

“…Recently, association of Indian B . pseudomallei isolates with Southeast Asian isolates have been reported by others as well [ 20 ].…”

“…Only 18 Indian STs were found to be singleton and were outliers. These singleton STs also included ST300 which was reported to be group founder in above study [ 20 ]. Topology and grouping of all Indian STs with other Asian and Australian STs by MEGA showed that majority of Indian isolates grouped together in one large group, however few STs were distant and unique particularly ST1636.…”

“…When analysed by eBURST, an algorithm which provides a hypothetical pattern of descent for the analyzed strains, most of the isolates of this study (or all Indian isolates available in MLST database) formed one clonal complex suggesting limited genotypic diversity. One of a predominant ST (ST1630) reported as singleton in a recent study [ 20 ], which was isolated from southern states of Tamil Nadu and Andhra Pradesh, also appeared to be part of this clonal complex. Only 18 Indian STs were found to be singleton and were outliers.…”

Prevalence and genetic diversity of Burkholderia pseudomallei isolates in the environment near a patient’s residence in Northeast Thailand

“…In addition, it is unknown if diverse genotypes differ in virulence, which might influence successful infection. This clinical isolate was belonged to ST99 which was previously reported in human in Philippines, Thailand, Malaysia and Bangladesh [36, 37]. ST99 was one of the most common stain in Taiwan, found in 24.7% (48/194) of clinical isolates collected during 2004 to 2010 [38].…”

“…ST99 was one of the most common stain in Taiwan, found in 24.7% (48/194) of clinical isolates collected during 2004 to 2010 [38]. In Thailand, ST99 was recovered from two soil samples and clinical specimens of two patients in Ubon Ratchathani, Northeast Thailand and in a patient in Songkhla province located in South Thailand [36]. The widespread dissemination distribution of this strain indicated that B .…”