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Klebsiella pneumoniae carbapenemase (KPC)-producing K. pneumoniae at a single institution: insights into endemicity from whole-genome sequencing.

Mathers AJ, Stoesser N, Sheppard AE, Pankhurst L, Giess A, Yeh AJ, Didelot X, Turner SD, Sebra R, Kasarskis A, Peto T, Crook D, Sifri CD - Antimicrob. Agents Chemother. (2015)

Bottom Line: Using WGS-based analysis of clinical isolates and plasmid transformants, we demonstrate the unexpected dispersal of blaKPC to many non-ST258 lineages in a hospital through spread of at least two novel blaKPC plasmids.In contrast, ST258 KPC-Kp was imported into the institution on numerous occasions, with other blaKPC plasmid vectors and without sustained transmission.Instead, a newly recognized KPC-Kp strain, ST941, became associated with both novel blaKPC plasmids and spread locally, making it a future candidate for clinical persistence and dissemination.

View Article: PubMed Central - PubMed

Affiliation: Division of Infectious Diseases and International Health, Department of Medicine, University of Virginia Health System, Charlottesville, Virginia, USA Clinical Microbiology, Department of Pathology, University of Virginia Health System, Charlottesville, Virginia, USA ajm5b@virginia.edu.

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Maximum likelihood phylogeny of core study Klebsiella pneumoniae carbapenemase (KPC)-producing K. pneumoniae sequences, in association with blaKPC allele, characterized Tn4401 isoforms, blaKPC plasmids (pKPC_UVA01 and pKPC_UVA02), and risk of within-hospital acquisition. Black circles at the nodes represent bootstrap values of >70% with the size of the circle reflecting the degree of support. The largest circles have bootstrap values of 100%. Tn4401 isoforms (a to e) and unclassified Tn4401 isoforms (*) are shown. Abbreviations: ST, sequence type; UVaHS/LTACH, University of Virginia Health System/long-term acute care hospital; SNVs, single-nucleotide variants.
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Figure 1: Maximum likelihood phylogeny of core study Klebsiella pneumoniae carbapenemase (KPC)-producing K. pneumoniae sequences, in association with blaKPC allele, characterized Tn4401 isoforms, blaKPC plasmids (pKPC_UVA01 and pKPC_UVA02), and risk of within-hospital acquisition. Black circles at the nodes represent bootstrap values of >70% with the size of the circle reflecting the degree of support. The largest circles have bootstrap values of 100%. Tn4401 isoforms (a to e) and unclassified Tn4401 isoforms (*) are shown. Abbreviations: ST, sequence type; UVaHS/LTACH, University of Virginia Health System/long-term acute care hospital; SNVs, single-nucleotide variants.

Mentions: Sixteen distinct STs were identified, two of which were novel, from the 37 K. pneumoniae isolates (Fig. 1; see Table S2 in the supplemental material). For the 11 and 13 isolates that had previously undergone traditional MLST and PFGE, respectively, the in silico MLST results matched the prior results, and the diversity seen on PFGE was also congruent with the WGS phylogeny (4, 36). Forty-six percent (17/37) of the isolates belonged to discrete STs with two or fewer isolates per ST. There were two STs represented by more than two isolates: ST941 (13/37 [35%]), which has not previously been described in association with blaKPC, and the epidemic ST258 (7/37 [19%]). None of the patients with ST258 KPC-Kp isolates were considered high risk for acquisition within UVaMC; five of the isolates were imported, and two patients had indeterminate risk (Fig. 1). All of the patients with ST941 were considered at high risk for acquisition within UVaMC. Excluding the indeterminate acquisition cases, patients with ST258 were more likely to acquire KPC-Kp outside UVaMC than non-ST258 (5/5 versus 2/26; P = 0.0001 by Fisher's exact test).


Klebsiella pneumoniae carbapenemase (KPC)-producing K. pneumoniae at a single institution: insights into endemicity from whole-genome sequencing.

Mathers AJ, Stoesser N, Sheppard AE, Pankhurst L, Giess A, Yeh AJ, Didelot X, Turner SD, Sebra R, Kasarskis A, Peto T, Crook D, Sifri CD - Antimicrob. Agents Chemother. (2015)

Maximum likelihood phylogeny of core study Klebsiella pneumoniae carbapenemase (KPC)-producing K. pneumoniae sequences, in association with blaKPC allele, characterized Tn4401 isoforms, blaKPC plasmids (pKPC_UVA01 and pKPC_UVA02), and risk of within-hospital acquisition. Black circles at the nodes represent bootstrap values of >70% with the size of the circle reflecting the degree of support. The largest circles have bootstrap values of 100%. Tn4401 isoforms (a to e) and unclassified Tn4401 isoforms (*) are shown. Abbreviations: ST, sequence type; UVaHS/LTACH, University of Virginia Health System/long-term acute care hospital; SNVs, single-nucleotide variants.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4325807&req=5

Figure 1: Maximum likelihood phylogeny of core study Klebsiella pneumoniae carbapenemase (KPC)-producing K. pneumoniae sequences, in association with blaKPC allele, characterized Tn4401 isoforms, blaKPC plasmids (pKPC_UVA01 and pKPC_UVA02), and risk of within-hospital acquisition. Black circles at the nodes represent bootstrap values of >70% with the size of the circle reflecting the degree of support. The largest circles have bootstrap values of 100%. Tn4401 isoforms (a to e) and unclassified Tn4401 isoforms (*) are shown. Abbreviations: ST, sequence type; UVaHS/LTACH, University of Virginia Health System/long-term acute care hospital; SNVs, single-nucleotide variants.
Mentions: Sixteen distinct STs were identified, two of which were novel, from the 37 K. pneumoniae isolates (Fig. 1; see Table S2 in the supplemental material). For the 11 and 13 isolates that had previously undergone traditional MLST and PFGE, respectively, the in silico MLST results matched the prior results, and the diversity seen on PFGE was also congruent with the WGS phylogeny (4, 36). Forty-six percent (17/37) of the isolates belonged to discrete STs with two or fewer isolates per ST. There were two STs represented by more than two isolates: ST941 (13/37 [35%]), which has not previously been described in association with blaKPC, and the epidemic ST258 (7/37 [19%]). None of the patients with ST258 KPC-Kp isolates were considered high risk for acquisition within UVaMC; five of the isolates were imported, and two patients had indeterminate risk (Fig. 1). All of the patients with ST941 were considered at high risk for acquisition within UVaMC. Excluding the indeterminate acquisition cases, patients with ST258 were more likely to acquire KPC-Kp outside UVaMC than non-ST258 (5/5 versus 2/26; P = 0.0001 by Fisher's exact test).

Bottom Line: Using WGS-based analysis of clinical isolates and plasmid transformants, we demonstrate the unexpected dispersal of blaKPC to many non-ST258 lineages in a hospital through spread of at least two novel blaKPC plasmids.In contrast, ST258 KPC-Kp was imported into the institution on numerous occasions, with other blaKPC plasmid vectors and without sustained transmission.Instead, a newly recognized KPC-Kp strain, ST941, became associated with both novel blaKPC plasmids and spread locally, making it a future candidate for clinical persistence and dissemination.

View Article: PubMed Central - PubMed

Affiliation: Division of Infectious Diseases and International Health, Department of Medicine, University of Virginia Health System, Charlottesville, Virginia, USA Clinical Microbiology, Department of Pathology, University of Virginia Health System, Charlottesville, Virginia, USA ajm5b@virginia.edu.

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Related in: MedlinePlus