Dataset Information

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

ABSTRACT:

Background

Burkholderia pseudomallei is the causative agent of melioidosis, a severe infectious disease in tropical regions. It is necessary to understand the risk of acquiring this infection from the environment.

Methodology /principal findings

The prevalence, concentration and genetic diversity of B. pseudomallei isolates collected from two sites in Buriram, Northeast Thailand were investigated. Forty-four environmental samples (18 from soil, 14 from rice rhizosphere, and 12 from water) were collected; of those 44 samples, 19 were collected from near a patient's residence and 25 from suspected exposure sites and compared with 10 clinical isolates of the patient. Quantitative culture was performed, and B. pseudomallei was identified using the latex agglutination test and matrix-laser absorption ionisation mass spectrometry. Genotyping was performed in 162 colonies from clinical (N = 10) and environmental samples (N = 152) using pulse-field gel electrophoresis (PFGE) followed by multi-locus sequence typing (MLST) of the clinical strain. B. pseudomallei was detected in 11 of the 44 environmental samples (1 from soil, 4 from rice rhizosphere, and 6 from water). The bacterial count in the positive soil sample was 115 CFU/g. The mean concentrations ± SDs of B. pseudomallei in the positive water and rhizosphere samples were 5.1 ± 5.5 CFU/ml and 80 ± 49 CFU/g, respectively. Six water samples with positive results were collected from a pond and water sources for drinking and daily use. All colonies isolated from the patient shared the same PFGE type (PT) indicating monoclonal infection of ST99. Although the 152 colonies from environmental isolates exhibited 25 PTs, none were identical to the patient's isolates. PT5 and PT7 were most common genotype among the environmental samples.

Conclusions/significance

Diverse genotypes of B. pseudomallei were prevalent in the environment. However, the patient may have been infected with a low-density genotype. Intervention strategies for preventing B. pseudomallei infection are required.

SUBMITTER: Seng R

PROVIDER: S-EPMC6493765 | biostudies-literature | 2019 Apr

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

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

Seng Rathanin R Saiprom Natnaree N Phunpang Rungnapa R Baltazar Christine Joy CJ Boontawee Sarika S Thodthasri Thanatchanan T Silakun Wirayut W Chantratita Narisara N

PLoS neglected tropical diseases 20190419 4

<h4>Background</h4>Burkholderia pseudomallei is the causative agent of melioidosis, a severe infectious disease in tropical regions. It is necessary to understand the risk of acquiring this infection from the environment.<h4>Methodology /principal findings</h4>The prevalence, concentration and genetic diversity of B. pseudomallei isolates collected from two sites in Buriram, Northeast Thailand were investigated. Forty-four environmental samples (18 from soil, 14 from rice rhizosphere, and 12 fro ...[more]

PMID: 31002718

Similar Datasets

Project description:Melioidosis, a severe bacterial illness caused by Burkholderia pseudomallei, is prevalent in most parts of Thailand, including its southern region situated within the Malay Peninsula. Despite a lower reported incidence rate of melioidosis in the South compared to the Northeast, the mortality rate remains persistently high. This study aimed to better understand the epidemiology and investigate the presence of B. pseudomallei in the natural environment of southern Thailand. Using multi-locus sequence typing (MLST), we characterized B. pseudomallei isolates derived from human cases and compared them with previously reported sequence types (STs) from the same region. A total of 263 clinical isolates retrieved from 156 melioidosis patients between 2014 and 2020 were analyzed, revealing 72 distinct STs, with 25 (35%) matching STs from Finkelstein's environmental isolates collected in southern Thailand during 1964-1967. Notably, strains bearing STs 288, 84, 54, 289, and 46 were frequently found among patients. Additionally, we observed strain diversity with multiple STs in 13 of 59 patients, indicating exposure to various B. pseudomallei genotypes in the environmental sources of the infection. Environmental surveys were conducted in Songkhla Province to detect B. pseudomallei in soil and water samples where local patients lived. Of the 2737 soil samples from 208 locations and 244 water samples from diverse sources, 52 (25%) soil sampling locations and 63 (26%) water sources were cultured positive for B. pseudomallei. Positive soil samples were predominantly found in animal farming area and non-agricultural zones like mountains and grasslands, while water samples were frequently positive in waterfalls, streams, and surface runoffs, with only 9% of rice paddies testing positive. Collectively, a significant proportion of recent melioidosis cases in Songkhla Province can be attributed to known B. pseudomallei STs persisting in the environment for at least the past six decades. Further characterization of B. pseudomallei isolates from recent environment surveys is warranted. These findings illuminate the contemporary landscape of B. pseudomallei infections and their environmental prevalence in southern Thailand, contributing to the regional threat assessment in Thailand and Southeast Asia.

Project description:Accurate identification of pathogens with biowarfare importance requires detection tools that specifically differentiate them from near-neighbor species. Burkholderia pseudomallei, the causative agent of a fatal disease melioidosis, is one such biothreat agent whose differentiation from its near-neighbor species is always a challenge. This is because of its phenotypic similarity with other Burkholderia species which have a wide spread geographical distribution with shared environmental niches. Melioidosis is a major public health concern in endemic regions including Southeast Asia and northern Australia. In India, the disease is still considered to be emerging. Prevalence surveys of this saprophytic bacterium in environment are under-reported in the country. A major challenge in this case is the specific identification and differentiation of B. pseudomallei from the growing list of species of Burkholderia genus. The objectives of this study included examining the prevalence of B. pseudomallei and near-neighbor species in coastal region of South India and development of a novel detection tool for specific identification and differentiation of Burkholderia species. Briefly, we analyzed soil and water samples collected from Malabar coastal region of Kerala, South India for prevalence of B. pseudomallei. The presumptive Burkholderia isolates were identified using recA PCR assay. The recA PCR assay identified 22 of the total 40 presumptive isolates as Burkholderia strains (22.72% and 77.27% B. pseudomallei and non-pseudomallei Burkholderia respectively). In order to identify each isolate screened, we performed recA and 16S rDNA sequencing. This two genes sequencing revealed that the presumptive isolates included B. pseudomallei, non-pseudomallei Burkholderia as well as non-Burkholderia strains. Furthermore, a gene termed D-beta hydroxybutyrate dehydrogenase (bdha) was studied both in silico and in vitro for accurate detection of Burkholderia genus. The optimized bdha based PCR assay when evaluated on the Burkholderia isolates of this study, it was found to be highly specific (100%) in its detection feature and a clear detection sensitivity of 10 pg/μl of purified gDNA was recorded. Nucleotide sequence variations of bdha among interspecies, as per in silico analysis, ranged from 8 to 29% within the target stretch of 730 bp highlighting the potential utility of bdha sequencing method in specific detection of Burkholderia species. Further, sequencing of the 730 bp bdha PCR amplicon of each Burkholderia strain isolated could differentiate the species and the data was comparable with recA sequence data of the strains. All sequencing results obtained were submitted to NCBI database. Bayesian phylogenetic analysis of bdha in comparison with recA and 16S rDNA showed that the bdha gene provided comparable identification of Burkholderia species.

Dataset Information

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

Background

Methodology /principal findings

Conclusions/significance

Publications

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

Similar Datasets

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