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Complete sequences of KPC-2-encoding plasmid p628-KPC and CTX-M-55-encoding p628-CTXM coexisted in Klebsiella pneumoniae.

Wang L, Fang H, Feng J, Yin Z, Xie X, Zhu X, Wang J, Chen W, Yang R, Du H, Zhou D - Front Microbiol (2015)

Bottom Line: A carbapenem-resistant Klebsiella pneumoniae strain 628 was isolated from a human case of intracranial infection in a Chinese teaching hospital.ΔTn3-ISKpn27-bla KPC-2-ΔISKpn6-ΔTn1722 and this transposon together with a mercury resistance (mer) gene locus constitutes a 34 kb acquired drug-resistance region. bla KPC-2 has two transcription starts (nucleotides G and C located at 39 and 250 bp upstream of its coding region respectively) which correspond to two promoters, i.e., the intrinsic P1 and the upstream ISKpn27/Tn3-provided P2 with the core -35/-10 elements TAATCC/TTACAT and TTGACA/AATAAT respectively. bla CTX-M-55 is mobilized in an ISEcp1-bla CTX-M-55-Δorf477 transposition unit and appears to be the sole drug-resistant determinant in p628-CTXM. bla CTX-M-55 possesses a single transcription start (nucleotides G located at 116 bp upstream of its coding region) corresponding to the ISEcp1-provided P1 promoter with the core -35/-10 element TTGAAA/TACAAT.All the above detected promoters display a characteristic of constitutive expression.

View Article: PubMed Central - PubMed

Affiliation: Department of Clinical Laboratory, The First Hospital Affiliated to Henan University Kaifeng, China.

ABSTRACT
A carbapenem-resistant Klebsiella pneumoniae strain 628 was isolated from a human case of intracranial infection in a Chinese teaching hospital. Strain 628 produces KPC-2 and CTX-M-55 encoded by two different conjugative plasmids, i.e., the IncFIIK plasmid p628-KPC and the IncI1 plasmid p628-CTXM respectively. bla KPC-2 is captured by a Tn1722-based unit transposon with a linear structure. ΔTn3-ISKpn27-bla KPC-2-ΔISKpn6-ΔTn1722 and this transposon together with a mercury resistance (mer) gene locus constitutes a 34 kb acquired drug-resistance region. bla KPC-2 has two transcription starts (nucleotides G and C located at 39 and 250 bp upstream of its coding region respectively) which correspond to two promoters, i.e., the intrinsic P1 and the upstream ISKpn27/Tn3-provided P2 with the core -35/-10 elements TAATCC/TTACAT and TTGACA/AATAAT respectively. bla CTX-M-55 is mobilized in an ISEcp1-bla CTX-M-55-Δorf477 transposition unit and appears to be the sole drug-resistant determinant in p628-CTXM. bla CTX-M-55 possesses a single transcription start (nucleotides G located at 116 bp upstream of its coding region) corresponding to the ISEcp1-provided P1 promoter with the core -35/-10 element TTGAAA/TACAAT. All the above detected promoters display a characteristic of constitutive expression. Coexistence of bla KPC and bla CTX-M in K. pneumoniae has been reported many times but this is the first report to gain deep insights into genetic platforms, promoters, and expression of the two coexisting bla genes with determination of entire nucleotide sequences of the two corresponding plasmids.

No MeSH data available.


Related in: MedlinePlus

Linear comparison of blaKPC−2 genetic surroundings. Genes are denoted by arrows and colored based on gene function classification.
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Figure 3: Linear comparison of blaKPC−2 genetic surroundings. Genes are denoted by arrows and colored based on gene function classification.

Mentions: As shown in Table 2 and Figure 3, the blaKPC−2 genetic environments from China can be assigned into three main categories: Tn4401 with the ISKpn7-blaKPC−2-ISKpn6 core structure (pKPC-NY79), the Tn1722-based unit transposons with the ISKpn27-blaKPC−2-ΔISKpn6 core structure [pKP048, p628-KPC, pHS062105-3, pKPHS2, pKPC-LK30, and pHS102707; ISKpn27 is initially named in the ISfinder database (Siguier et al., 2006)], and the IS26-based composite transposons with the ISKpn27-blaKPC−2-ΔISKpn6 core structure (pKPC-LKEc, pECN580, and pKo6). The Tn4401 of pKPC-NY79 is a novel isoform of Tn4401a with tnpR truncated. The prototype Tn1722-based transposon as observed in pKP048 has a linear structure Δmcp-Tn3-ISKpn27-blaKPC−2-ΔISKpn6-korC-klcA-unkown ORF-ΔrepB- Tn1722. Various truncations within the 5′ terminal Δmcp-Tn3 region can be identified for different KPC-encoding plasmids from China; in p628-KPC, a truncation within Δmcp-Tn3 leaves only a 402 bp remnant of the Tn3 tnpR gene at the 5′ end of Tn1722-based transposon. Interestingly, an IS26-based composite transposon, which is almost identical to the counterpart in pHK23 (recovered from pig-derived E. coli in China) and harbors the fosfomycin resistance gene fosA3 (Ho et al., 2013a), is inserted into the tnpRA locus of Tn1722 in pHS102707, leaving tnpR and tnpA truncated. The IS26-based blaKPC−2-carrying transposons have a basic linear structure IS26-ΔTn3-ISKpn27-blaKPC−2-ΔISKpn6-IS26, for which presence of two IS26 elements at both ends truncates ISKpn6 and Tn3; notably, different lengths of truncated ISKpn6 can be observed for these IS26-based transposons from different plasmids.


Complete sequences of KPC-2-encoding plasmid p628-KPC and CTX-M-55-encoding p628-CTXM coexisted in Klebsiella pneumoniae.

Wang L, Fang H, Feng J, Yin Z, Xie X, Zhu X, Wang J, Chen W, Yang R, Du H, Zhou D - Front Microbiol (2015)

Linear comparison of blaKPC−2 genetic surroundings. Genes are denoted by arrows and colored based on gene function classification.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4541600&req=5

Figure 3: Linear comparison of blaKPC−2 genetic surroundings. Genes are denoted by arrows and colored based on gene function classification.
Mentions: As shown in Table 2 and Figure 3, the blaKPC−2 genetic environments from China can be assigned into three main categories: Tn4401 with the ISKpn7-blaKPC−2-ISKpn6 core structure (pKPC-NY79), the Tn1722-based unit transposons with the ISKpn27-blaKPC−2-ΔISKpn6 core structure [pKP048, p628-KPC, pHS062105-3, pKPHS2, pKPC-LK30, and pHS102707; ISKpn27 is initially named in the ISfinder database (Siguier et al., 2006)], and the IS26-based composite transposons with the ISKpn27-blaKPC−2-ΔISKpn6 core structure (pKPC-LKEc, pECN580, and pKo6). The Tn4401 of pKPC-NY79 is a novel isoform of Tn4401a with tnpR truncated. The prototype Tn1722-based transposon as observed in pKP048 has a linear structure Δmcp-Tn3-ISKpn27-blaKPC−2-ΔISKpn6-korC-klcA-unkown ORF-ΔrepB- Tn1722. Various truncations within the 5′ terminal Δmcp-Tn3 region can be identified for different KPC-encoding plasmids from China; in p628-KPC, a truncation within Δmcp-Tn3 leaves only a 402 bp remnant of the Tn3 tnpR gene at the 5′ end of Tn1722-based transposon. Interestingly, an IS26-based composite transposon, which is almost identical to the counterpart in pHK23 (recovered from pig-derived E. coli in China) and harbors the fosfomycin resistance gene fosA3 (Ho et al., 2013a), is inserted into the tnpRA locus of Tn1722 in pHS102707, leaving tnpR and tnpA truncated. The IS26-based blaKPC−2-carrying transposons have a basic linear structure IS26-ΔTn3-ISKpn27-blaKPC−2-ΔISKpn6-IS26, for which presence of two IS26 elements at both ends truncates ISKpn6 and Tn3; notably, different lengths of truncated ISKpn6 can be observed for these IS26-based transposons from different plasmids.

Bottom Line: A carbapenem-resistant Klebsiella pneumoniae strain 628 was isolated from a human case of intracranial infection in a Chinese teaching hospital.ΔTn3-ISKpn27-bla KPC-2-ΔISKpn6-ΔTn1722 and this transposon together with a mercury resistance (mer) gene locus constitutes a 34 kb acquired drug-resistance region. bla KPC-2 has two transcription starts (nucleotides G and C located at 39 and 250 bp upstream of its coding region respectively) which correspond to two promoters, i.e., the intrinsic P1 and the upstream ISKpn27/Tn3-provided P2 with the core -35/-10 elements TAATCC/TTACAT and TTGACA/AATAAT respectively. bla CTX-M-55 is mobilized in an ISEcp1-bla CTX-M-55-Δorf477 transposition unit and appears to be the sole drug-resistant determinant in p628-CTXM. bla CTX-M-55 possesses a single transcription start (nucleotides G located at 116 bp upstream of its coding region) corresponding to the ISEcp1-provided P1 promoter with the core -35/-10 element TTGAAA/TACAAT.All the above detected promoters display a characteristic of constitutive expression.

View Article: PubMed Central - PubMed

Affiliation: Department of Clinical Laboratory, The First Hospital Affiliated to Henan University Kaifeng, China.

ABSTRACT
A carbapenem-resistant Klebsiella pneumoniae strain 628 was isolated from a human case of intracranial infection in a Chinese teaching hospital. Strain 628 produces KPC-2 and CTX-M-55 encoded by two different conjugative plasmids, i.e., the IncFIIK plasmid p628-KPC and the IncI1 plasmid p628-CTXM respectively. bla KPC-2 is captured by a Tn1722-based unit transposon with a linear structure. ΔTn3-ISKpn27-bla KPC-2-ΔISKpn6-ΔTn1722 and this transposon together with a mercury resistance (mer) gene locus constitutes a 34 kb acquired drug-resistance region. bla KPC-2 has two transcription starts (nucleotides G and C located at 39 and 250 bp upstream of its coding region respectively) which correspond to two promoters, i.e., the intrinsic P1 and the upstream ISKpn27/Tn3-provided P2 with the core -35/-10 elements TAATCC/TTACAT and TTGACA/AATAAT respectively. bla CTX-M-55 is mobilized in an ISEcp1-bla CTX-M-55-Δorf477 transposition unit and appears to be the sole drug-resistant determinant in p628-CTXM. bla CTX-M-55 possesses a single transcription start (nucleotides G located at 116 bp upstream of its coding region) corresponding to the ISEcp1-provided P1 promoter with the core -35/-10 element TTGAAA/TACAAT. All the above detected promoters display a characteristic of constitutive expression. Coexistence of bla KPC and bla CTX-M in K. pneumoniae has been reported many times but this is the first report to gain deep insights into genetic platforms, promoters, and expression of the two coexisting bla genes with determination of entire nucleotide sequences of the two corresponding plasmids.

No MeSH data available.


Related in: MedlinePlus