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Discovering and differentiating new and emerging clonal populations of Chlamydia trachomatis with a novel shotgun cell culture harvest assay.

Somboonna N, Mead S, Liu J, Dean D - Emerging Infect. Dis. (2008)

Bottom Line: We developed a novel shotgun cell culture harvest assay for this purpose because we found that recent clinical samples do not form plaques.Clones were strain-typed by using outer membrane protein A and 16S rRNA sequences.Three clonal variants of reference strain Ba/Apache-2 were also identified.

View Article: PubMed Central - PubMed

Affiliation: Children's Hospital, Oakland Research Institute, Oakland, California, USA.

ABSTRACT
Chlamydia trachomatis is the leading cause of preventable blindness and bacterial sexually transmitted diseases worldwide. Plaque assays have been used to clonally segregate laboratory-adapted C. trachomatis strains from mixed infections, but no assays have been reported to segregate clones from recent clinical samples. We developed a novel shotgun cell culture harvest assay for this purpose because we found that recent clinical samples do not form plaques. Clones were strain-typed by using outer membrane protein A and 16S rRNA sequences. Surprisingly, ocular trachoma reference strain A/SA-1 contained clones of Chlamydophila abortus. C. abortus primarily infects ruminants and pigs and has never been identified in populations where trachoma is endemic. Three clonal variants of reference strain Ba/Apache-2 were also identified. Our findings reflect the importance of clonal isolation in identifying constituents of mixed infections containing new or emerging strains and of viable clones for research to more fully understand the dynamics of in vivo strain-mixing, evolution, and disease pathogenesis.

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Related in: MedlinePlus

Neighbor-joining trees representing evolutionary relatedness of the 19 reference strains, Chlamydophila abortus and 5 clonal variants based on ompA nucleotide (A) and amino acid (B) sequence alignments. The trees were constructed from ClustalW 1.8 alignment (www.ebi.ac.uk/Tools/clustalw2/index.html), and the values at the nodes are the bootstrap confidence levels calculated from 1,000 bootstrap resamplings. See Materials and Methods for details.
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Figure 4: Neighbor-joining trees representing evolutionary relatedness of the 19 reference strains, Chlamydophila abortus and 5 clonal variants based on ompA nucleotide (A) and amino acid (B) sequence alignments. The trees were constructed from ClustalW 1.8 alignment (www.ebi.ac.uk/Tools/clustalw2/index.html), and the values at the nodes are the bootstrap confidence levels calculated from 1,000 bootstrap resamplings. See Materials and Methods for details.

Mentions: Phylogenetics of ompA nucleotide and amino acid sequence alignments were performed to evaluate divergence of 5 clonal variants of Ba/Apache-2 and F/IC-Cal3. The trees showed the clustering of the 5 clonal variants with their respective parental strains (Figure 4, panels A and B).


Discovering and differentiating new and emerging clonal populations of Chlamydia trachomatis with a novel shotgun cell culture harvest assay.

Somboonna N, Mead S, Liu J, Dean D - Emerging Infect. Dis. (2008)

Neighbor-joining trees representing evolutionary relatedness of the 19 reference strains, Chlamydophila abortus and 5 clonal variants based on ompA nucleotide (A) and amino acid (B) sequence alignments. The trees were constructed from ClustalW 1.8 alignment (www.ebi.ac.uk/Tools/clustalw2/index.html), and the values at the nodes are the bootstrap confidence levels calculated from 1,000 bootstrap resamplings. See Materials and Methods for details.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2570839&req=5

Figure 4: Neighbor-joining trees representing evolutionary relatedness of the 19 reference strains, Chlamydophila abortus and 5 clonal variants based on ompA nucleotide (A) and amino acid (B) sequence alignments. The trees were constructed from ClustalW 1.8 alignment (www.ebi.ac.uk/Tools/clustalw2/index.html), and the values at the nodes are the bootstrap confidence levels calculated from 1,000 bootstrap resamplings. See Materials and Methods for details.
Mentions: Phylogenetics of ompA nucleotide and amino acid sequence alignments were performed to evaluate divergence of 5 clonal variants of Ba/Apache-2 and F/IC-Cal3. The trees showed the clustering of the 5 clonal variants with their respective parental strains (Figure 4, panels A and B).

Bottom Line: We developed a novel shotgun cell culture harvest assay for this purpose because we found that recent clinical samples do not form plaques.Clones were strain-typed by using outer membrane protein A and 16S rRNA sequences.Three clonal variants of reference strain Ba/Apache-2 were also identified.

View Article: PubMed Central - PubMed

Affiliation: Children's Hospital, Oakland Research Institute, Oakland, California, USA.

ABSTRACT
Chlamydia trachomatis is the leading cause of preventable blindness and bacterial sexually transmitted diseases worldwide. Plaque assays have been used to clonally segregate laboratory-adapted C. trachomatis strains from mixed infections, but no assays have been reported to segregate clones from recent clinical samples. We developed a novel shotgun cell culture harvest assay for this purpose because we found that recent clinical samples do not form plaques. Clones were strain-typed by using outer membrane protein A and 16S rRNA sequences. Surprisingly, ocular trachoma reference strain A/SA-1 contained clones of Chlamydophila abortus. C. abortus primarily infects ruminants and pigs and has never been identified in populations where trachoma is endemic. Three clonal variants of reference strain Ba/Apache-2 were also identified. Our findings reflect the importance of clonal isolation in identifying constituents of mixed infections containing new or emerging strains and of viable clones for research to more fully understand the dynamics of in vivo strain-mixing, evolution, and disease pathogenesis.

Show MeSH
Related in: MedlinePlus