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Burkholderia pseudomallei sequence type 562 in China and Australia.

Chen H, Xia L, Zhu X, Li W, Du X, Wu D, Hai R, Shen X, Liang Y, Cai H, Zheng X - Emerging Infect. Dis. (2015)

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Melioidosis is increasingly being recognized in tropical and subtropical areas worldwide; the world’s 2 major endemic foci are Thailand and northern Australia... Phylogenetic analyses of Burkholderia pseudomallei isolates, performed by using multilocus sequence typing (MLST), have led to phylogeographic associations that can be used to track melioidosis epidemics... However, in contrast to the previous separation of B. pseudomallei into 2 phylogenetic groups (Australia and Southeast Asia/rest of the world), we report an MLST sequence type (ST) that seems to be present in northern Australia, Taiwan, and southern China... We characterized clinical isolates of B. pseudomallei from the 110 cases by using MLST, pulsed-field gel electrophoresis (PFGE), and 4-locus multilocus variable-number tandem-repeat analysis (MLVA-4)... ST167 accounted for 1 of the 110 B. pseudomallei strains from Hainan... The narK locus of ST167contains allele 3 instead of allele 29, as seen in ST562; 3 base differences are found in allele 3: C72T (C→T position 72), C126T, and A435G... Two mutually exclusive gene clusters, B. thailandensis–like flagellar gene cluster (BTFC) and Yersinia-like fimbrial gene cluster (YLF), have been linked to geographic origin and have been suggested for differentiating groups of B. pseudomallei... By PCR we found that ST562 isolates of Hainan were all YLF positive... Presence of YLF was also observed in strains from Papua New Guinea, possibly reflecting that country’s location, intermediate between major foci of melioidosis... In conclusion, by using MLST and the online MLST database, we revealed that B. pseudomallei ST562 is present in southern China as well as in Australia and Taiwan... The intercontinental character of this ST raises new questions about the epidemiology and control of melioidosis... Given the usual geographic separation of B. pseudomallei STs, we suggest that this wide-ranging presence of ST562 might result from more recent spread caused by transmission between regions... Increasing farming exchanges and trade of agricultural products between melioidosis-endemic regions might facilitate breaking of the geographic barrier; clonal introduction of B. pseudomallei could potentially occur in new locations... Improved and cooperative surveillance is required for elucidating the current and future global dispersion range of B. pseudomallei and for monitoring the consequent melioidosis infections... Geographic distribution of 43 Burkholderia pseudomallei sequence type 562 strains identified in Australia; Taiwan; and Hainan, China, during 2004–2012.

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Pulsed-field gel electrophoresis (PFGE) patterns for 3 sequence type (ST) 562 and 1 ST167 Burkholderia pseudomallei strains isolated during 2008–2012, Hainan, China. The isolate source, isolation time, ST, and 4-locus multilocus variable-number tandem-repeat analysis (4-MLVA) profiles are indicated for each strain. Scale bar indicates percentage similarity.
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Figure 1: Pulsed-field gel electrophoresis (PFGE) patterns for 3 sequence type (ST) 562 and 1 ST167 Burkholderia pseudomallei strains isolated during 2008–2012, Hainan, China. The isolate source, isolation time, ST, and 4-locus multilocus variable-number tandem-repeat analysis (4-MLVA) profiles are indicated for each strain. Scale bar indicates percentage similarity.

Mentions: Of the 3 patients from Hainan from whom ST562 strains were isolated, 2 resided in the city of Sanya and 1 in the neighboring city of Lingshui (Technical Appendix); all denied a history of foreign travel, they shared no common risk factors, and all survived the infection. Further analysis of ST562, performed by using eBURST-based (http://eburst.mlst.net/) population analysis of the MLST dataset, showed that ST562 is a single-locus variant of ST167, which is represented on the MLST dataset by multiple human and environmental isolates from Thailand and to date by 1 human isolate from Cambodia. ST167 accounted for 1 of the 110 B. pseudomallei strains from Hainan. The narK locus of ST167contains allele 3 instead of allele 29, as seen in ST562; 3 base differences are found in allele 3: C72T (C→T position 72), C126T, and A435G. According to PFGE, the 3 ST562 isolates from Hainan displayed a single pulsotype, and the other 107 isolates from Hainan belonged to distinct and diverse pulsotypes, similar to those observed in Taiwan. The uniformity of PFGE patterns in the Hainan and Taiwan isolates supports the possibility that ST562 might be a recently emerging clone. PFGE patterns of Hainan ST562 exhibited 86% similarity with ST167, differing by 6 bands (Figure).


Burkholderia pseudomallei sequence type 562 in China and Australia.

Chen H, Xia L, Zhu X, Li W, Du X, Wu D, Hai R, Shen X, Liang Y, Cai H, Zheng X - Emerging Infect. Dis. (2015)

Pulsed-field gel electrophoresis (PFGE) patterns for 3 sequence type (ST) 562 and 1 ST167 Burkholderia pseudomallei strains isolated during 2008–2012, Hainan, China. The isolate source, isolation time, ST, and 4-locus multilocus variable-number tandem-repeat analysis (4-MLVA) profiles are indicated for each strain. Scale bar indicates percentage similarity.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4285272&req=5

Figure 1: Pulsed-field gel electrophoresis (PFGE) patterns for 3 sequence type (ST) 562 and 1 ST167 Burkholderia pseudomallei strains isolated during 2008–2012, Hainan, China. The isolate source, isolation time, ST, and 4-locus multilocus variable-number tandem-repeat analysis (4-MLVA) profiles are indicated for each strain. Scale bar indicates percentage similarity.
Mentions: Of the 3 patients from Hainan from whom ST562 strains were isolated, 2 resided in the city of Sanya and 1 in the neighboring city of Lingshui (Technical Appendix); all denied a history of foreign travel, they shared no common risk factors, and all survived the infection. Further analysis of ST562, performed by using eBURST-based (http://eburst.mlst.net/) population analysis of the MLST dataset, showed that ST562 is a single-locus variant of ST167, which is represented on the MLST dataset by multiple human and environmental isolates from Thailand and to date by 1 human isolate from Cambodia. ST167 accounted for 1 of the 110 B. pseudomallei strains from Hainan. The narK locus of ST167contains allele 3 instead of allele 29, as seen in ST562; 3 base differences are found in allele 3: C72T (C→T position 72), C126T, and A435G. According to PFGE, the 3 ST562 isolates from Hainan displayed a single pulsotype, and the other 107 isolates from Hainan belonged to distinct and diverse pulsotypes, similar to those observed in Taiwan. The uniformity of PFGE patterns in the Hainan and Taiwan isolates supports the possibility that ST562 might be a recently emerging clone. PFGE patterns of Hainan ST562 exhibited 86% similarity with ST167, differing by 6 bands (Figure).

View Article: PubMed Central - PubMed

AUTOMATICALLY GENERATED EXCERPT
Please rate it.

Melioidosis is increasingly being recognized in tropical and subtropical areas worldwide; the world’s 2 major endemic foci are Thailand and northern Australia... Phylogenetic analyses of Burkholderia pseudomallei isolates, performed by using multilocus sequence typing (MLST), have led to phylogeographic associations that can be used to track melioidosis epidemics... However, in contrast to the previous separation of B. pseudomallei into 2 phylogenetic groups (Australia and Southeast Asia/rest of the world), we report an MLST sequence type (ST) that seems to be present in northern Australia, Taiwan, and southern China... We characterized clinical isolates of B. pseudomallei from the 110 cases by using MLST, pulsed-field gel electrophoresis (PFGE), and 4-locus multilocus variable-number tandem-repeat analysis (MLVA-4)... ST167 accounted for 1 of the 110 B. pseudomallei strains from Hainan... The narK locus of ST167contains allele 3 instead of allele 29, as seen in ST562; 3 base differences are found in allele 3: C72T (C→T position 72), C126T, and A435G... Two mutually exclusive gene clusters, B. thailandensis–like flagellar gene cluster (BTFC) and Yersinia-like fimbrial gene cluster (YLF), have been linked to geographic origin and have been suggested for differentiating groups of B. pseudomallei... By PCR we found that ST562 isolates of Hainan were all YLF positive... Presence of YLF was also observed in strains from Papua New Guinea, possibly reflecting that country’s location, intermediate between major foci of melioidosis... In conclusion, by using MLST and the online MLST database, we revealed that B. pseudomallei ST562 is present in southern China as well as in Australia and Taiwan... The intercontinental character of this ST raises new questions about the epidemiology and control of melioidosis... Given the usual geographic separation of B. pseudomallei STs, we suggest that this wide-ranging presence of ST562 might result from more recent spread caused by transmission between regions... Increasing farming exchanges and trade of agricultural products between melioidosis-endemic regions might facilitate breaking of the geographic barrier; clonal introduction of B. pseudomallei could potentially occur in new locations... Improved and cooperative surveillance is required for elucidating the current and future global dispersion range of B. pseudomallei and for monitoring the consequent melioidosis infections... Geographic distribution of 43 Burkholderia pseudomallei sequence type 562 strains identified in Australia; Taiwan; and Hainan, China, during 2004–2012.

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Related in: MedlinePlus