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Full sequence and comparative analysis of the plasmid pAPEC-1 of avian pathogenic E. coli chi7122 (O78:K80:H9).

Mellata M, Touchman JW, Curtiss R - PLoS ONE (2009)

Bottom Line: The full length of the transfer region in pAPEC-1 (11 kb) is shorter compared to the tra region of other sequenced F plasmids; the absence of some tra genes in pAPEC-1 affects its self-transferability, and the conjugative function of the plasmid was effective only in the presence of other plasmids.The presence of pAPEC-1-associated genes is assessed in human ExPEC by PCR.Many patterns of association between genes are found.

View Article: PubMed Central - PubMed

Affiliation: The Biodesign Institute, Arizona State University, Tempe, Arizona, United States of America.

ABSTRACT

Background: Extra-intestinal pathogenic E. coli (ExPEC), including Avian Pathogenic E. coli (APEC), are very diverse. They cause a complex of diseases in Human, animals, and birds. Even though large plasmids are often associated with the virulence of ExPEC, their characterization is still in its infancy.

Methodology/principal findings: We fully sequenced and analyzed the large plasmid pAPEC-1 (103,275-bp) associated with the APEC strain chi7122, from worldwide serogroup O78ratioK80ratioH9. A putative virulence region spanning an 80-kb region of pAPEC-1 possesses four iron acquisition systems (iutA iucABCD, sitABCD, iroBCDN, and temperature-sensitive hemagglutinin tsh), a colicin V operon, increasing serum sensitivity iss, ompT, hlyF, and etsABC. Thirty three ORFs in pAPEC-1 are identified as insertion sequences (ISs) that belong to nine families with diverse origins. The full length of the transfer region in pAPEC-1 (11 kb) is shorter compared to the tra region of other sequenced F plasmids; the absence of some tra genes in pAPEC-1 affects its self-transferability, and the conjugative function of the plasmid was effective only in the presence of other plasmids. Two-replicon systems, repFIIA-repFIC and repFIB, and two post-segregational systems, srnB and hok/sok, are also present in the sequence of pAPEC-1. The comparison of the pAPEC-1 sequence with the two available plasmid sequences reveals more gene loss and reorganization than previously appreciated. The presence of pAPEC-1-associated genes is assessed in human ExPEC by PCR. Many patterns of association between genes are found.

Conclusions/significance: The pathotype typical of pAPEC-1 was present in some human strains, which indicates a horizontal transfer between strains and the zoonotic risk of APEC strains. ColV plasmids could have common virulence genes that could be acquired by transposition, without sharing genes of plasmid function.

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Plasmid profiles of strains on 0.5% agarose gel (A).Four plasmids (147 kb, 63 kb, 35.85 kb, and 6.9 kb) of the strain 39R681 [83] were used as a ladder (L). Each lane contained plasmids from the following bacterial strains: (1) χ7122, (2) χ7273, (3) χ7277, (4) 7345, (5) 7346, (6) χ7396, (7) χ833, (8) χ2934, (9) χ6092, (10) MGN-617, and (11) TOP10; Colicin production of strains (B). (1) χ7122, (2) χ6092, (3) χ7346.
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pone-0004232-g001: Plasmid profiles of strains on 0.5% agarose gel (A).Four plasmids (147 kb, 63 kb, 35.85 kb, and 6.9 kb) of the strain 39R681 [83] were used as a ladder (L). Each lane contained plasmids from the following bacterial strains: (1) χ7122, (2) χ7273, (3) χ7277, (4) 7345, (5) 7346, (6) χ7396, (7) χ833, (8) χ2934, (9) χ6092, (10) MGN-617, and (11) TOP10; Colicin production of strains (B). (1) χ7122, (2) χ6092, (3) χ7346.

Mentions: APEC strain χ7122 (O78∶K80∶H9), isolated from liver of a deceased Turkey [22], possesses three large plasmids [[16], Fig. 1]; the largest of these three plasmids is termed pAPEC-1 and is considered to be the virulence plasmid of χ7122 [16]. The APEC strain χ7122 (Nalr) was mated with an E. coli K-12 χ6092 (Tcr), an avirulent strain lacking plasmids. The transconjugant χ7346 was selected on MacConkey agar containing tetracycline and colicin V synthesized in vitro from the χ7122 as described before [23].


Full sequence and comparative analysis of the plasmid pAPEC-1 of avian pathogenic E. coli chi7122 (O78:K80:H9).

Mellata M, Touchman JW, Curtiss R - PLoS ONE (2009)

Plasmid profiles of strains on 0.5% agarose gel (A).Four plasmids (147 kb, 63 kb, 35.85 kb, and 6.9 kb) of the strain 39R681 [83] were used as a ladder (L). Each lane contained plasmids from the following bacterial strains: (1) χ7122, (2) χ7273, (3) χ7277, (4) 7345, (5) 7346, (6) χ7396, (7) χ833, (8) χ2934, (9) χ6092, (10) MGN-617, and (11) TOP10; Colicin production of strains (B). (1) χ7122, (2) χ6092, (3) χ7346.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2626276&req=5

pone-0004232-g001: Plasmid profiles of strains on 0.5% agarose gel (A).Four plasmids (147 kb, 63 kb, 35.85 kb, and 6.9 kb) of the strain 39R681 [83] were used as a ladder (L). Each lane contained plasmids from the following bacterial strains: (1) χ7122, (2) χ7273, (3) χ7277, (4) 7345, (5) 7346, (6) χ7396, (7) χ833, (8) χ2934, (9) χ6092, (10) MGN-617, and (11) TOP10; Colicin production of strains (B). (1) χ7122, (2) χ6092, (3) χ7346.
Mentions: APEC strain χ7122 (O78∶K80∶H9), isolated from liver of a deceased Turkey [22], possesses three large plasmids [[16], Fig. 1]; the largest of these three plasmids is termed pAPEC-1 and is considered to be the virulence plasmid of χ7122 [16]. The APEC strain χ7122 (Nalr) was mated with an E. coli K-12 χ6092 (Tcr), an avirulent strain lacking plasmids. The transconjugant χ7346 was selected on MacConkey agar containing tetracycline and colicin V synthesized in vitro from the χ7122 as described before [23].

Bottom Line: The full length of the transfer region in pAPEC-1 (11 kb) is shorter compared to the tra region of other sequenced F plasmids; the absence of some tra genes in pAPEC-1 affects its self-transferability, and the conjugative function of the plasmid was effective only in the presence of other plasmids.The presence of pAPEC-1-associated genes is assessed in human ExPEC by PCR.Many patterns of association between genes are found.

View Article: PubMed Central - PubMed

Affiliation: The Biodesign Institute, Arizona State University, Tempe, Arizona, United States of America.

ABSTRACT

Background: Extra-intestinal pathogenic E. coli (ExPEC), including Avian Pathogenic E. coli (APEC), are very diverse. They cause a complex of diseases in Human, animals, and birds. Even though large plasmids are often associated with the virulence of ExPEC, their characterization is still in its infancy.

Methodology/principal findings: We fully sequenced and analyzed the large plasmid pAPEC-1 (103,275-bp) associated with the APEC strain chi7122, from worldwide serogroup O78ratioK80ratioH9. A putative virulence region spanning an 80-kb region of pAPEC-1 possesses four iron acquisition systems (iutA iucABCD, sitABCD, iroBCDN, and temperature-sensitive hemagglutinin tsh), a colicin V operon, increasing serum sensitivity iss, ompT, hlyF, and etsABC. Thirty three ORFs in pAPEC-1 are identified as insertion sequences (ISs) that belong to nine families with diverse origins. The full length of the transfer region in pAPEC-1 (11 kb) is shorter compared to the tra region of other sequenced F plasmids; the absence of some tra genes in pAPEC-1 affects its self-transferability, and the conjugative function of the plasmid was effective only in the presence of other plasmids. Two-replicon systems, repFIIA-repFIC and repFIB, and two post-segregational systems, srnB and hok/sok, are also present in the sequence of pAPEC-1. The comparison of the pAPEC-1 sequence with the two available plasmid sequences reveals more gene loss and reorganization than previously appreciated. The presence of pAPEC-1-associated genes is assessed in human ExPEC by PCR. Many patterns of association between genes are found.

Conclusions/significance: The pathotype typical of pAPEC-1 was present in some human strains, which indicates a horizontal transfer between strains and the zoonotic risk of APEC strains. ColV plasmids could have common virulence genes that could be acquired by transposition, without sharing genes of plasmid function.

Show MeSH
Related in: MedlinePlus