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Fulltext Molecular investigations of a locally acquired case of melioidosis in Southern AZ, USA

Engelthaler DM, Bowers J, Schupp JA, Pearson T, Ginther J, Hornstra HM, et al.

PLoS Negl Trop Dis, 2011 Oct;5(10):e1347.
PMID: 22028940 DOI: 10.1371/journal.pntd.0001347

Melioidosis is caused by Burkholderia pseudomallei, a Gram-negative bacillus, primarily found in soils in Southeast Asia and northern Australia. A recent case of melioidosis in non-endemic Arizona was determined to be the result of locally acquired infection, as the patient had no travel history to endemic regions and no previous history of disease. Diagnosis of the case was confirmed through multiple microbiologic and molecular techniques. To enhance the epidemiological analysis, we conducted several molecular genotyping procedures, including multi-locus sequence typing, SNP-profiling, and whole genome sequence typing. Each technique has different molecular epidemiologic advantages, all of which provided evidence that the infecting strain was most similar to those found in Southeast Asia, possibly originating in, or around, Malaysia. Advancements in new typing technologies provide genotyping resolution not previously available to public health investigators, allowing for more accurate source identification.

Matched MeSH terms: Burkholderia pseudomallei/classification*
DNA fingerprinting of septicemic and localized Burkholderia pseudomallei isolates from Malaysian patients

Azura MN, Norazah A, Kamel AG, Zorin SA

Southeast Asian J. Trop. Med. Public Health, 2011 Jan;42(1):114-21.
PMID: 21323173

We have analysed DNA fingerprinting patterns by pulsed-field gel electrophoresis (PFGE) of 52 unrelated Burkholderia pseudomallei strains isolated from septicemic and localized infections from Malaysian subjects. A total of 38 PFGE types were observed among 36 septicemic and 16 localized strains with no predominant pattern. Type 25 was seen in 2 epidemiologically related strains, suggesting human to human transmission. Twelve PFGE types were shared among 26 strains (21 septicemic and 5 localized) showing close genetic relatedness with coefficient of similarity of 0.81 to 1.0. The other 26 strains (15 septicemic and 11 localized) were unrelated as shown by the similarity coefficient of < 0.8. This study showed that our B. pseudomallei strains in Malaysia were mainly heterogenous with no predominant type both in septicemic or localized strains.

Matched MeSH terms: Burkholderia pseudomallei/classification
SpeI restriction enzyme displays greater discriminatory power than XbaI enzyme does in a pulsed-field gel electrophoresis study on 146 clinical Burkholderia pseudomallei isolates

Chua KH, See KH, Thong KL, Puthucheary SD

Jpn J Infect Dis, 2011;64(3):228-33.
PMID: 21617308

Restriction enzymes SpeI and XbaI were used in a pulsed-field gel electrophoresis (PFGE) study for molecular characterization of 146 clinical Burkholderia pseudomallei isolates. The PFGE parameters were optimized to enable comparable, reproducible, and robust results. The optimized parameters for both SpeI and XbaI restriction enzymes used in this study were 200 V and a pulse time of 5 to 65 s for a 28-h runtime. Using SpeI, 9 different clusters were identified, whereas 6 clusters were identified by XbaI digestion, which exhibited 85% similarity to SpeI. SpeI (discrimination index [D]=0.854) showed higher discriminatory power than XbaI did (D=0.464).

Matched MeSH terms: Burkholderia pseudomallei/classification*
Stability of strain genotypes of Burkholderia pseudomallei from patients with single and recurrent episodes of melioidosis

Vadivelu J, Puthucheary SD, Drasar BS, Dance DA, Pitt TL

Trop Med Int Health, 1998 Jul;3(7):518-21.
PMID: 9705184

The constancy of strain genotypes of multiple isolates of Burkholderia pseudomallei from 13 patients with melioidosis was examined by BamHI ribotyping and pulsed-field gel electrophoresis (PFGE) of XbaI digests of DNA. Seven of 8 patients with single episodes of melioidosis each yielded genetically identical isolates and only one of five patients with recurrent episodes was infected with a new strain clearly distinct from the original primary strain. Variation was observed in PFGE patterns of primary and relapse isolates of another patient but this was insufficient to define genetically distinct strains. We conclude that most patients with single or multiple episodes of melioidosis retain a single strain.

Matched MeSH terms: Burkholderia pseudomallei/classification
Fulltext Reliability of automated biochemical identification of Burkholderia pseudomallei is regionally dependent

Podin Y, Kaestli M, McMahon N, Hennessy J, Ngian HU, Wong JS, et al.

J Clin Microbiol, 2013 Sep;51(9):3076-8.
PMID: 23784129 DOI: 10.1128/JCM.01290-13

Misidentifications of Burkholderia pseudomallei as Burkholderia cepacia by Vitek 2 have occurred. Multidimensional scaling ordination of biochemical profiles of 217 Malaysian and Australian B. pseudomallei isolates found clustering of misidentified B. pseudomallei isolates from Malaysian Borneo. Specificity of B. pseudomallei identification in Vitek 2 and potentially other automated identification systems is regionally dependent.

Matched MeSH terms: Burkholderia pseudomallei/classification
Fulltext Sequence polymorphism and PCR-restriction fragment length polymorphism analysis of the flagellin gene of Burkholderia pseudomallei

Tay ST, Cheah PC, Puthucheary SD

J Clin Microbiol, 2010 Apr;48(4):1465-7.
PMID: 20089759 DOI: 10.1128/JCM.01131-09

Four flagellin allelic types (I to IV) of Burkholderia pseudomallei were identified based on their sequence variation and restriction fragment length polymorphism (RFLP) analysis of the amplified flagellin gene. Flagellin allelic type I was the most predominantly (75.0%) found among the 100 clinical isolates of B. pseudomallei investigated in this study.

Matched MeSH terms: Burkholderia pseudomallei/classification*
Fulltext An imported case of acute melioidosis caused by ST881 Burkholderia pseudomallei

Zong Z, Wang X, Deng Y

Southeast Asian J. Trop. Med. Public Health, 2016 Mar;47(2):219-22.
PMID: 27244959

A previously healthy Chinese male working in Malaysia returned to China with high fever. A blood culture showed Burkholderia pseudomallei strain WCBP1. This isolate was sequenced, showing type, ST881, which appears to be present in Malaysia. WCP1 had unusual susceptibility to aminoglycosides and habored the Yersinia-like fimbrial gene cluster for virulence. The patient's condition deteriorated rapidly but he recovered after receiving meropenem and intensive care support. Melioidosis is a potential problem among Chinese imigrant workers with strains new to China being identified.

Matched MeSH terms: Burkholderia pseudomallei/classification
Characterization of Burkholderia pseudomallei isolated in Thailand and Malaysia

Radua S, Ling OW, Srimontree S, Lulitanond A, Hin WF, Yuherman, et al.

Diagn Microbiol Infect Dis, 2000 Nov;38(3):141-5.
PMID: 11109011

A total of 35 Burkholderia pseudomallei isolates from Thailand (16 clinical and eight soil isolates) and Malaysia (seven animal, two isolate each from clinical and soil) were investigated by their antimicrobial resistance, plasmid profiles and were typed by randomly amplified polymorphic DNA analysis. All isolates were found to be resistant to six or more of the 12 antimicrobial agents tested. Only two small plasmids of 1.8 and 2.4 megadalton were detected in two clinical isolates from Thailand. RAPD analysis with primer GEN2-60-09 resulted in the identification of 35 RAPD-types among the 35 isolates. The constructed dendrogram differentiated the 35 isolates into two main clusters and a single isolate. The wide genetic biodiversity among the 35 isolates indicate that RAPD-PCR can be a useful method to differentiate unrelated B. pseudomallei in epidemiological investigation.

Matched MeSH terms: Burkholderia pseudomallei/classification*
Misidentification of Burkholderia pseudomallei as Burkholderia cepacia by the VITEK 2 system

Zong Z, Wang X, Deng Y, Zhou T

J Med Microbiol, 2012 Oct;61(Pt 10):1483-1484.
PMID: 22820689 DOI: 10.1099/jmm.0.041525-0

A previously healthy Chinese male returned from working in the Malaysian jungle with a fever. A blood culture grew Gram-negative bacilli that were initially identified as Burkholderia cepacia by the VITEK 2 system but were subsequently found to be Burkholderia pseudomallei by partial sequencing of the 16S rRNA gene. The identification of B. pseudomallei using commercially available automated systems is problematic and clinicians in non-endemic areas should be aware of the possibility of melioidosis in patients with a relevant travel history and blood cultures growing Burkholderia spp.

Matched MeSH terms: Burkholderia pseudomallei/classification*
Fulltext DNA fingerprinting of human isolates of Burkholderia pseudomallei from different geographical regions of Malaysia

Chua KH, See KH, Thong KL, Puthucheary SD

Trop Biomed, 2010 Dec;27(3):517-24.
PMID: 21399594 MyJurnal

Melioidosis is an infectious disease caused by Burkholderia pseudomallei and endemic in Southeast Asia. One hundred and forty six clinical isolates of B. pseudomallei from different states in Malaysia were obtained and molecular typing was carried out using pulsed-field gel electrophoresis (PFGE). Overall, nine clusters were successfully identified. Burkholderia pseudomallei isolates used in this study were found to be genetically diverse and there were differences in the clusters of isolates from peninsular and east Malaysia. BS9 cluster was the most common cluster and found in all the states while BS2 cluster only existed in a particular state. Based on the PFGE analysis, the distribution of different B. pseudomallei clinical isolates in Malaysia was mapped.

Matched MeSH terms: Burkholderia pseudomallei/classification*
Fulltext Whole-genome comparative analysis of Malaysian Burkholderia pseudomallei clinical isolates

Ghazali AK, Eng SA, Khoo JS, Teoh S, Hoh CC, Nathan S

Microb Genom, 2021 02;7(2).
PMID: 33565959 DOI: 10.1099/mgen.0.000527

Burkholderia pseudomallei, a soil-dwelling Gram-negative bacterium, is the causative agent of the endemic tropical disease melioidosis. Clinical manifestations of B. pseudomallei infection range from acute or chronic localized infection in a single organ to fulminant septicaemia in multiple organs. The diverse clinical manifestations are attributed to various factors, including the genome plasticity across B. pseudomallei strains. We previously characterized B. pseudomallei strains isolated in Malaysia and noted different levels of virulence in model hosts. We hypothesized that the difference in virulence might be a result of variance at the genome level. In this study, we sequenced and assembled four Malaysian clinical B. pseudomallei isolates, UKMR15, UKMPMC2000, UKMD286 and UKMH10. Phylogenomic analysis showed that Malaysian subclades emerged from the Asian subclade, suggesting that the Malaysian strains originated from the Asian region. Interestingly, the low-virulence strain, UKMH10, was the most distantly related compared to the other Malaysian isolates. Genomic island (GI) prediction analysis identified a new island of 23 kb, GI9c, which is present in B. pseudomallei and Burkholderia mallei, but not Burkholderia thailandensis. Genes encoding known B. pseudomallei virulence factors were present across all four genomes, but comparative analysis of the total gene content across the Malaysian strains identified 104 genes that are absent in UKMH10. We propose that these genes may encode novel virulence factors, which may explain the reduced virulence of this strain. Further investigation on the identity and role of these 104 proteins may aid in understanding B. pseudomallei pathogenicity to guide the design of new therapeutics for treating melioidosis.

Matched MeSH terms: Burkholderia pseudomallei/classification*
Fulltext Multilocus sequence types of clinical Burkholderia pseudomallei isolates from peninsular Malaysia and their associations with disease outcomes

Zueter AR, Rahman ZA, Abumarzouq M, Harun A

BMC Infect Dis, 2018 01 02;18(1):5.
PMID: 29291714 DOI: 10.1186/s12879-017-2912-9

BACKGROUND: Previous studies on the Burkholderia pseudomallei genetic diversity among clinical isolates from melioidosis-endemic areas have identified genetic factors contributing to differential virulence. Although it has been ruled out in Australian and Thai B. pseudomallei populations, it remains unclear whether B. pseudomallei sequence types (STs) correlate with disease in Malaysian patients with melioidosis.
METHODS: In this study, multi-locus sequence typing (MLST) was performed on clinical B. pseudomallei isolates collected from Kelantan state of Malaysia, patients' clinical data were reviewed and then genotype-risk correlations were investigated.
RESULTS: Genotyping of 83 B. pseudomallei isolates revealed 32 different STs, of which 13(40%) were novel. The frequencies of the STs among the 83 isolates ranged from 1 to 12 observations, and ST54, ST371 and ST289 were predominant. All non-novel STs reported in this study have also been identified in other Asian countries. Based on the MLST data analysis, the phylogenetic tree showed clustering of the STs with each other, as well as with the STs from Southeast Asia and China. No evidence for associations between any of B. pseudomallei STs and clinical melioidosis presentation was detected. In addition, the bacterial genotype clusters in relation with each clinical outcome were statistically insignificant, and no risk estimate was reported. This study has expanded the data for B. pseudomallei on MLST database map and provided insights into the molecular epidemiology of melioidosis in Peninsular Malaysia.
CONCLUSION: This study concurs with previous reports concluding that infecting strain type plays no role in determining disease presentation.

Matched MeSH terms: Burkholderia pseudomallei/classification
Multilocus sequence typing of historical Burkholderia pseudomallei isolates collected in Southeast Asia from 1964 to 1967 provides insight into the epidemiology of melioidosis

McCombie RL, Finkelstein RA, Woods DE

J Clin Microbiol, 2006 Aug;44(8):2951-62.
PMID: 16891516

A collection of 207 historically relevant Burkholderia pseudomallei isolates was analyzed by multilocus sequence typing (MLST). The strain collection contains environmental isolates obtained from a geographical distribution survey of B. pseudomallei isolates in Thailand (1964 to 1967), as well as stock cultures and colony variants from the U.S. Army Medical Research Unit (Malaysia), the Walter Reed Army Institute for Research, and the Pasteur Institute (Vietnam). The 207 isolates of the collection were resolved into 80 sequence types (STs); 56 of these were novel. eBURST diagrams predict that the historical-collection STs segregate into three complexes when analyzed separately. When added to the 760 isolates and 365 STs of the B. pseudomallei MLST database, the historical-collection STs cluster significantly within the main complex of the eBURST diagram in an ancestral pattern and alter the B. pseudomallei "population snapshot." Differences in colony morphology among reference isolates were found not to affect the STs assigned, which were consistent with the original isolates. Australian ST84 is likely characteristic of B. pseudomallei isolates of Southeast Asia rather than Australia, since multiple environmental isolates from Thailand and Malaysia share this ST with the single Australian clinical isolate in the MLST database. Phylogenetic evidence is also provided suggesting that Australian isolates may not be distinct from those of Thailand, since ST60 is common to environmental isolates from both countries. MLST and eBURST are useful tools for the study of population biology and epidemiology, since they provide methods to elucidate new genetic relationships among bacterial isolates.

Matched MeSH terms: Burkholderia pseudomallei/classification*
Burkholderia pseudomallei animal and human isolates from Malaysia exhibit different phenotypic characteristics

Lee SH, Chong CE, Lim BS, Chai SJ, Sam KK, Mohamed R, et al.

Diagn Microbiol Infect Dis, 2007 Jul;58(3):263-70.
PMID: 17350202

Burkholderia pseudomallei is a Gram-negative saprophytic soil bacterium, which is the etiologic agent of melioidosis, a severe and fatal infectious disease occurring in human and animals. Distinct clinical and animal isolates have been shown to exhibit differences in phenotypic trait such as growth rate, colony morphology, antimicrobial resistance, and virulence. This study was carried out to gain insight into the intrinsic differences between 4 clinical and 6 animal B. pseudomallei isolates from Malaysia. The 16S rRNA-encoding genes from these 10 isolates of B. pseudomallei were sequenced to confirm the identity of these isolates along with the avirulent Burkholderia thailandensis. The nucleotide sequences indicated that the 16S rRNA-encoding genes among the 10 B. pseudomallei isolates were identical to each other. However, the nucleotide sequence differences in the 16S rRNA-encoding genes appeared to be B. pseudomallei and B. thailandensis specific. The growth rate of all B. pseudomallei isolates was determined by generating growth curves at 37 degrees C for 72 h. The isolates were found to differ in growth rates with doubling time varying from 1.5 to 2.3 h. In addition, the B. pseudomallei isolates exhibited considerable variation in colony morphology when grown on Ashdown media, brain-heart infusion agar, and Luria-Bertani agar over 9 days of observation. Antimicrobial susceptibility tests indicated that 80% of the isolates examined were Amp(R) Cb(R) Kn(R) Gm(R) Chl(S) Te(S). Virulence of the B. pseudomallei clinical and animal isolates was evaluated in B. pseudomallei-susceptible BALB/c mice. Most of the clinical isolates were highly virulent. However, virulence did not correlate with isolate origin since 2 of the animal isolates were also highly virulent.

Matched MeSH terms: Burkholderia pseudomallei/classification*

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