Multiple phylogenetically-diverse, differentially-virulent Burkholderia pseudomallei isolated from a single soil sample collected in Thailand
Issued Date
2022-02-01
Resource Type
ISSN
19352727
eISSN
19352735
Scopus ID
2-s2.0-85125212551
Pubmed ID
35143500
Journal Title
PLoS Neglected Tropical Diseases
Volume
16
Issue
2
Rights Holder(s)
SCOPUS
Bibliographic Citation
PLoS Neglected Tropical Diseases Vol.16 No.2 (2022)
Suggested Citation
Roe C. Multiple phylogenetically-diverse, differentially-virulent Burkholderia pseudomallei isolated from a single soil sample collected in Thailand. PLoS Neglected Tropical Diseases Vol.16 No.2 (2022). doi:10.1371/journal.pntd.0010172 Retrieved from: https://repository.li.mahidol.ac.th/handle/123456789/86134
Title
Multiple phylogenetically-diverse, differentially-virulent Burkholderia pseudomallei isolated from a single soil sample collected in Thailand
Author(s)
Author's Affiliation
Other Contributor(s)
Abstract
Burkholderia pseudomallei is a soil-dwelling bacterium endemic to Southeast Asia and northern Australia that causes the disease, melioidosis. Although the global genomic diversity of clinical B. pseudomallei isolates has been investigated, there is limited understanding of its genomic diversity across small geographic scales, especially in soil. In this study, we obtained 288 B. pseudomallei isolates from a single soil sample (~100g; intensive site 2, INT2) collected at a depth of 30cm from a site in Ubon Ratchathani Province, Thailand. We sequenced the genomes of 169 of these isolates that represent 7 distinct sequence types (STs), including a new ST (ST1820), based on multi-locus sequence typing (MLST) analy-sis. A core genome SNP phylogeny demonstrated that all identified STs share a recent common ancestor that diverged an estimated 796–1260 years ago. A pan-genomics analysis demonstrated recombination between clades and intra-MLST phylogenetic and gene differ-ences. To identify potential differential virulence between STs, groups of BALB/c mice (5 mice/isolate) were challenged via subcutaneous injection (500 CFUs) with 30 INT2 isolates representing 5 different STs; over the 21-day experiment, eight isolates killed all mice, 2 isolates killed an intermediate number of mice (1–2), and 20 isolates killed no mice. Although the virulence results were largely stratified by ST, one virulent isolate and six attenuated isolates were from the same ST (ST1005), suggesting that variably conserved genomic regions may contribute to virulence. Genomes from the animal-challenged isolates were subjected to a bacterial genome-wide association study to identify genomic regions associated with differential virulence. One associated region is a unique variant of Hcp1, a component of the type VI secretion system, which may result in attenuation. The results of this study have implications for comprehensive sampling strategies, environmental exposure risk assessment, and understanding recombination and differential virulence in B. pseudomallei.