scholarly journals Iron Acquisition and Siderophore Release by Carbapenem-Resistant Sequence Type 258 Klebsiella pneumoniae

mSphere ◽  
2018 ◽  
Vol 3 (2) ◽  
pp. e00125-18 ◽  
Author(s):  
Victoria I. Holden ◽  
Meredith S. Wright ◽  
Sébastien Houle ◽  
Abigail Collingwood ◽  
Charles M. Dozois ◽  
...  
Keyword(s):  
Klebsiella Pneumoniae ◽  
Iron Acquisition ◽  
Expression Patterns ◽  
The United States ◽  
Sequence Type ◽  
Iron Limitation ◽  
Transcriptional Responses ◽  
Content Type ◽  
Carbapenem Resistant ◽  
Wide Range

ABSTRACT Klebsiella pneumoniae is rapidly acquiring resistance to all known antibiotics, including carbapenems. Multilocus sequence type ST258 (sequence type 258), carrying a gene encoding the K. pneumoniae carbapenemase (blaKPC) on a transmissible plasmid, is the most prevalent carbapenem-resistant Enterobacteriaceae (CRE) in the United States and has disseminated worldwide. Previously, whole-genome sequencing identified core genome single nucleotide variants that divide ST258 into two distinct clades, ST258a and ST258b. Furthermore, a subset of ST258b strains have a 347-base deletion within the enterobactin (Ent) exporter gene entS. Despite the predicted inability of these strains to secrete the siderophore Ent, this clade is prevalent among clinical isolates, indicating that a full-length entS gene is not necessary for infection. To compare the transcriptional responses of ST258 subtypes to iron limitation, we performed transcriptome sequencing (RNA-Seq) in minimal medium alone or supplemented with iron or human serum and measured gene expression patterns. Iron limitation induced differential expression of distinct iron acquisition pathways when comparing ST258a and ST258b strains, including the upregulation of the hemin transport operon in entS partial deletion isolates. To measure how K. pneumoniae strains vary in iron chelation and siderophore production, we performed in vitro chrome azurol S (CAS) and Arnow assays as well as mass spectrometry. We determined that both ST258a and ST258b strains grow under iron-depleted conditions, can utilize hemin for growth, and secrete Ent, despite the partial entS deletion in a subset of ST258b strains. All carbapenem-resistant (CR) K. pneumoniae strains tested were susceptible to growth inhibition by the Ent-sequestering innate immune protein lipocalin 2. IMPORTANCE Carbapenem-resistant Enterobacteriaceae, including K. pneumoniae, are a major health care concern worldwide because they cause a wide range of infection and are resistant to all or nearly all antibiotics. To cause infection, these bacteria must acquire iron, and a major mechanism of acquiring iron is by secreting a molecule called enterobactin that strips iron from host proteins. However, a subset of carbapenem-resistant K. pneumoniae strains that lack a portion of the entS gene that is required for enterobactin secretion was recently discovered. To understand how these mutant strains obtain iron, we studied their transcriptional responses, bacterial growth, and enterobactin secretion under iron-limited conditions. We found that strains both with mutated and intact entS genes grow under iron-limiting conditions, secrete enterobactin, and utilize an alternate iron source, hemin, for growth. Our data indicate that carbapenem-resistant K. pneumoniae can use varied methods for iron uptake during infection.

scholarly journals Multiplex PCR Analysis for Rapid Detection of Klebsiella pneumoniae Carbapenem-Resistant (Sequence Type 258 [ST258] and ST11) and Hypervirulent (ST23, ST65, ST86, and ST375) Strains

2018 ◽  
Vol 56 (9) ◽  
Author(s):  
Fangyou Yu ◽  
Jingnan Lv ◽  
Siqiang Niu ◽  
Hong Du ◽  
Yi-Wei Tang ◽  
...  
Keyword(s):  
United States ◽  
Klebsiella Pneumoniae ◽  
Multiplex Pcr ◽  
Virulence Genes ◽  
The United States ◽  
Sequence Type ◽  
Pcr Assay ◽  
Content Type ◽  
Carbapenem Resistant ◽  
Resistant Strains

ABSTRACT Carbapenem-resistant and hypervirulent Klebsiella pneumoniae strains have emerged recently. These strains are both hypervirulent and multidrug resistant and may also be highly transmissible and able to cause severe infections in both the hospital and the community. Clinical and public health needs require a rapid and comprehensive molecular detection assay to identify and track the spread of these strains and provide timely infection control information. Here, we develop a rapid multiplex PCR assay capable of distinguishing K. pneumoniae carbapenem-resistant isolates of sequence type 258 (ST258) and ST11, and hypervirulent ST23, ST65/ST375, and ST86 clones, as well as capsular types K1, K2, K locus type 47 (KL47), and KL64, and virulence genes rmpA, rmpA2, iutA, and iroN. The assay demonstrated 100% concordance with 118 previously genotyped K. pneumoniae isolates and revealed different populations of carbapenem-resistant and hypervirulent strains in two collections in China and the United States. The results showed that carbapenem-resistant and hypervirulent K. pneumoniae strains are still rare in the United States, whereas in China, ∼50% of carbapenem-resistant strains carry rmpA/rmpA2 and iutA virulence genes, which are largely associated with the epidemic ST11 strains. Similarly, a high prevalence of hypervirulent strains was found in carbapenem-susceptible isolates in two Chinese hospitals, but these primarily belong to ST23, ST65/ST375, and ST86, which are distinct from the carbapenem-resistant strains. Taken together, our results demonstrated that this PCR assay can be a useful tool for molecular surveillance of carbapenem-resistant and hypervirulent K. pneumoniae strains.

scholarly journals Colistin Resistance in Carbapenem-Resistant Klebsiella pneumoniae Mediated by Chromosomal Integration of Plasmid DNA

2017 ◽  
Vol 61 (8) ◽  
Author(s):  
Astrid V. Cienfuegos-Gallet ◽  
Liang Chen ◽  
Barry N. Kreiswirth ◽  
J. Natalia Jiménez
Keyword(s):  
Klebsiella Pneumoniae ◽  
Plasmid Dna ◽  
Clonal Expansion ◽  
Genetic Alterations ◽  
Sequence Type ◽  
Chromosomal Integration ◽  
Colistin Resistance ◽  
Content Type ◽  
Carbapenem Resistant ◽  
Single Locus Variant

ABSTRACT Here we describe the spread of colistin resistance in clinical isolates of carbapenem-resistant Klebsiella pneumoniae in Medellín, Colombia. Among 32 isolates collected between 2012 and 2014, 24 showed genetic alterations in mgrB. Nineteen isolates belonged to sequence type 512 (ST512) (or its single locus variant [SLV]) and harbored an 8.1-kb hsdMSR insertion corresponding to ISKpn25, indicating a clonal expansion of the resistant strain. The insertion region showed 100% identity to several plasmids, suggesting that the colistin resistance is mediated by chromosomal integration of plasmid DNA.

scholarly journals Colistin Heteroresistance Is Largely Undetected among Carbapenem-Resistant Enterobacterales in the United States

mBio ◽  
2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Victor I. Band ◽  
Sarah W. Satola ◽  
Richard D. Smith ◽  
David A. Hufnagel ◽  
Chris Bower ◽  
...  
Keyword(s):  
United States ◽  
Klebsiella Pneumoniae ◽  
Diagnostic Testing ◽  
Cladistic Analysis ◽  
The United States ◽  
Clinical Diagnostics ◽  
Infection Model ◽  
Content Type ◽  
Carbapenem Resistant ◽  
Clinical Diagnostic

ABSTRACT Heteroresistance is a form of antibiotic resistance where a bacterial strain is comprised of a minor resistant subpopulation and a majority susceptible subpopulation. We showed previously that colistin heteroresistance can mediate the failure of colistin therapy in an in vivo infection model, even for isolates designated susceptible by clinical diagnostics. We sought to characterize the extent of colistin heteroresistance among the highly drug-resistant carbapenem-resistant Enterobacterales (CRE). We screened 408 isolates for colistin heteroresistance. These isolates were collected between 2012 and 2015 in eight U.S. states as part of active surveillance for CRE. Colistin heteroresistance was detected in 10.1% (41/408) of isolates, and it was more common than conventional homogenous resistance (7.1%, 29/408). Most (93.2%, 38/41) of these heteroresistant isolates were classified as colistin susceptible by standard clinical diagnostic testing. The frequency of colistin heteroresistance was greatest in 2015, the last year of the study. This was especially true among Enterobacter isolates, of which specific species had the highest rates of heteroresistance. Among Klebsiella pneumoniae isolates, which were the majority of isolates tested, there was a closely related cluster of colistin-heteroresistant ST-258 isolates found mostly in Georgia. However, cladistic analysis revealed that, overall, there was significant diversity in the genetic backgrounds of heteroresistant K. pneumoniae isolates. These findings suggest that due to being largely undetected in the clinic, colistin heteroresistance among CRE is underappreciated in the United States. IMPORTANCE Heteroresistance is an underappreciated phenomenon that may be the cause of some unexplained antibiotic treatment failures. Misclassification of heteroresistant isolates as susceptible may lead to inappropriate therapy. Heteroresistance to colistin was more common than conventional resistance and was overwhelmingly misclassified as susceptibility by clinical diagnostic testing. Higher proportions of colistin heteroresistance observed in certain Enterobacter species and clustering among heteroresistant Klebsiella pneumoniae strains may inform colistin treatment recommendations. Overall, the rate of colistin nonsusceptibility was more than double the level detected by clinical diagnostics, suggesting that the prevalence of colistin nonsusceptibility among CRE may be higher than currently appreciated in the United States.

scholarly journals Sequence Type 273 Carbapenem-Resistant Klebsiella pneumoniae Carrying bla NDM-1 and bla IMP-4

2018 ◽  
Vol 62 (6) ◽  
Author(s):  
Lu Liu ◽  
Yu Feng ◽  
Haiyan Long ◽  
Alan McNally ◽  
Zhiyong Zong
Keyword(s):  
Klebsiella Pneumoniae ◽  
Southeast Asia ◽  
Human Blood ◽  
Sequence Type ◽  
Whole Genome Sequence ◽  
Whole Genome ◽  
Content Type ◽  
Carbapenem Resistant ◽  
Transmissible Plasmid ◽  
Long Read

ABSTRACT A carbapenem-resistant Klebsiella pneumoniae isolate was recovered from human blood. Its whole-genome sequence was obtained using Illumina and long-read MinION sequencing. The strain belongs to sequence type 273 (ST273), which was found recently and caused an outbreak in Southeast Asia. It has two carbapenemase genes, bla NDM-1 (carried by an ST7 IncN self-transmissible plasmid) and bla IMP-4 (located on a self-transmissible IncHI5 plasmid). Non-KPC-producing ST237 may represent a lineage of carbapenem-resistant K. pneumoniae , which warrants further monitoring.

scholarly journals Vaccine Protection against Multidrug-Resistant Klebsiella pneumoniae in a Nonhuman Primate Model of Severe Lower Respiratory Tract Infection

mBio ◽  
2019 ◽  
Vol 10 (6) ◽  
Author(s):  
Natalia Malachowa ◽  
Scott D. Kobayashi ◽  
Adeline R. Porter ◽  
Brett Freedman ◽  
Patrick W. Hanley ◽  
...  
Keyword(s):  
United States ◽  
Risk Factors ◽  
Health Care ◽  
Lower Respiratory Tract ◽  
The United States ◽  
Multidrug Resistant ◽  
Sequence Type ◽  
Content Type ◽  
Carbapenem Resistant ◽  
Cynomolgus Macaques

ABSTRACT Klebsiella pneumoniae is a human gut communal organism and notorious opportunistic pathogen. The relative high burden of asymptomatic colonization by K. pneumoniae is often compounded by multidrug resistance—a potential problem for individuals with significant comorbidities or other risk factors for infection. A carbapenem-resistant K. pneumoniae strain classified as multilocus sequence type 258 (ST258) is widespread in the United States and is usually multidrug resistant. Thus, treatment of ST258 infections is often difficult. Inasmuch as new preventive and/or therapeutic measures are needed for treatment of such infections, we developed an ST258 pneumonia model in cynomolgus macaques and tested the ability of an ST258 capsule polysaccharide type 2 (CPS2) vaccine to moderate disease severity. Compared with sham-vaccinated animals, those vaccinated with ST258 CPS2 had significantly less disease as assessed by radiography 24 h after intrabronchial installation of 108 CFU of ST258. All macaques vaccinated with CPS2 ultimately developed ST258-specific antibodies that significantly enhanced serum bactericidal activity and killing of ST258 by macaque neutrophils ex vivo. Consistent with a protective immune response to CPS2, transcripts encoding inflammatory mediators were increased in infected lung tissues obtained from CPS-vaccinated animals compared with control, sham-vaccinated macaques. Taken together, our data provide support for the idea that vaccination with ST258 CPS can be used to prevent or moderate infections caused by ST258. As with studies performed decades earlier, we propose that this prime-boost vaccination approach can be extended to include multiple capsule types. IMPORTANCE Multidrug-resistant bacteria continue to be a major problem worldwide, especially among individuals with significant comorbidities and other risk factors for infection. K. pneumoniae is among the leading causes of health care-associated infections, and the organism is often resistant to multiple classes of antibiotics. A carbapenem-resistant K. pneumoniae strain known as multilocus sequence type 258 (ST258) is the predominant carbapenem-resistant Enterobacteriaceae in the health care setting in the United States. Infections caused by ST258 are often difficult to treat and new prophylactic measures and therapeutic approaches are needed. To that end, we developed a lower respiratory tract infection model in cynomolgus macaques in which to test the ability of ST258 CPS to protect against severe ST258 infection.

scholarly journals Nacubactam Enhances Meropenem Activity against Carbapenem-Resistant Klebsiella pneumoniae Producing KPC

2019 ◽  
Vol 63 (8) ◽  
Author(s):  
Melissa D. Barnes ◽  
Magdalena A. Taracila ◽  
Caryn E. Good ◽  
Saralee Bajaksouzian ◽  
Laura J. Rojas ◽  
...  
Keyword(s):  
Molecular Modeling ◽  
Klebsiella Pneumoniae ◽  
The United States ◽  
Alternative Mechanism ◽  
Enhancer Activity ◽  
Content Type ◽  
Class A ◽  
Carbapenem Resistant ◽  
Biochemical Analyses ◽  
Molecular Modeling And Docking

ABSTRACT Carbapenem-resistant Enterobacteriaceae (CRE) are resistant to most antibiotics, making CRE infections extremely difficult to treat with available agents. Klebsiella pneumoniae carbapenemases (KPC-2 and KPC-3) are predominant carbapenemases in CRE in the United States. Nacubactam is a bridged diazabicyclooctane (DBO) β-lactamase inhibitor that inactivates class A and C β-lactamases and exhibits intrinsic antibiotic and β-lactam “enhancer” activity against Enterobacteriaceae. In this study, we examined a collection of meropenem-resistant K. pneumoniae isolates carrying blaKPC-2 or blaKPC-3; meropenem-nacubactam restored susceptibility. Upon testing isogenic Escherichia coli strains producing KPC-2 variants with single-residue substitutions at important Ambler class A positions (K73, S130, R164, E166, N170, D179, K234, E276, etc.), the K234R variant increased the meropenem-nacubactam MIC compared to that for the strain producing KPC-2, without increasing the meropenem MIC. Correspondingly, nacubactam inhibited KPC-2 (apparent Ki [Ki app] = 31 ± 3 μM) more efficiently than the K234R variant (Ki app = 270 ± 27 μM) and displayed a faster acylation rate (k2/K), which was 5,815 ± 582 M−1 s−1 for KPC-2 versus 247 ± 25 M−1 s−1 for the K234R variant. Unlike avibactam, timed mass spectrometry revealed an intact sulfate on nacubactam and a novel peak (+337 Da) with the K234R variant. Molecular modeling of the K234R variant showed significant catalytic residue (i.e., S70, K73, and S130) rearrangements that likely interfere with nacubactam binding and acylation. Nacubactam’s aminoethoxy tail formed unproductive interactions with the K234R variant’s active site. Molecular modeling and docking observations were consistent with the results of biochemical analyses. Overall, the meropenem-nacubactam combination is effective against carbapenem-resistant K. pneumoniae. Moreover, our data suggest that β-lactamase inhibition by nacubactam proceeds through an alternative mechanism compared to that for avibactam.

scholarly journals ARGONAUT II Study of the In Vitro Activity of Plazomicin against Carbapenemase-Producing Klebsiella pneumoniae

2020 ◽  
Vol 64 (5) ◽  
Author(s):  
Michael R. Jacobs ◽  
Caryn E. Good ◽  
Andrea M. Hujer ◽  
Ayman M. Abdelhamed ◽  
Daniel D. Rhoads ◽  
...  
Keyword(s):  
United States ◽  
16S Rrna ◽  
Klebsiella Pneumoniae ◽  
Great Lakes ◽  
The United States ◽  
Great Lakes Region ◽  
In Vitro Activity ◽  
Content Type ◽  
Carbapenem Resistant

ABSTRACT Plazomicin was tested against 697 recently acquired carbapenem-resistant Klebsiella pneumoniae isolates from the Great Lakes region of the United States. Plazomicin MIC50 and MIC90 values were 0.25 and 1 mg/liter, respectively; 680 isolates (97.6%) were susceptible (MICs of ≤2 mg/liter), 9 (1.3%) intermediate (MICs of 4 mg/liter), and 8 (1.1%) resistant (MICs of >32 mg/liter). Resistance was associated with rmtF-, rmtB-, or armA-encoded 16S rRNA methyltransferases in all except 1 isolate.

scholarly journals Complete Sequence of ablaKPC-2-Harboring IncFIIK1Plasmid from a Klebsiella pneumoniae Sequence Type 258 Strain

2013 ◽  
Vol 57 (3) ◽  
pp. 1542-1545 ◽  
Author(s):  
Liang Chen ◽  
Kalyan D. Chavda ◽  
Roberto G. Melano ◽  
Michael R. Jacobs ◽  
Michael H. Levi ◽  
...  
Keyword(s):  
New York ◽  
New York City ◽  
Nucleotide Sequence ◽  
Klebsiella Pneumoniae ◽  
York City ◽  
Complete Sequence ◽  
Sequence Type ◽  
Content Type ◽  
City Area ◽  
Carbapenem Resistant

ABSTRACTWe report the nucleotide sequence of a novelblaKPC-2-harboring IncFIIK1plasmid, pBK32179, isolated from a carbapenem-resistantKlebsiella pneumoniaeST258 strain from a New York City patient. pBK32179 is 165 kb long, consists of a large backbone of pKPN3-like plasmid, and carries an 18.5-kbblaKPC-2-containing element that is highly similar to plasmid pKpQIL. pBK32179-like plasmids were identified in 8.3% of strains in a collection of 96K. pneumoniaeisolates from hospitals in the New York City area.

scholarly journals Carbapenem-Resistant Klebsiella pneumoniae Strains Exhibit Diversity in Aminoglycoside-Modifying Enzymes, Which Exert Differing Effects on Plazomicin and Other Agents

2014 ◽  
Vol 58 (8) ◽  
pp. 4443-4451 ◽  
Author(s):  
Reem Almaghrabi ◽  
Cornelius J. Clancy ◽  
Yohei Doi ◽  
Binghua Hao ◽  
Liang Chen ◽  
...  
Keyword(s):  
Antimicrobial Resistance ◽  
Klebsiella Pneumoniae ◽  
Bactericidal Activity ◽  
Sequence Type ◽  
Content Type ◽  
Molecular Assays ◽  
Carbapenem Resistant ◽  
Research Priority ◽  
Gentamicin Resistance

ABSTRACTWe measuredin vitroactivity of plazomicin, a next-generation aminoglycoside, and other aminoglycosides against 50 carbapenem-resistantKlebsiella pneumoniaestrains from two centers and correlated the results with the presence of various aminoglycoside-modifying enzymes (AMEs). Ninety-four percent of strains were sequence type 258 (ST258) clones, which exhibited 5ompK36genotypes; 80% and 10% of strains producedKlebsiella pneumoniaecarbapenemase 2 (KPC-2) and KPC-3, respectively. Ninety-eight percent of strains possessed AMEs, including AAC(6′)-Ib (98%), APH(3′)-Ia (56%), AAC(3)-IV (38%), and ANT(2″)-Ia (2%). Gentamicin, tobramycin, and amikacin nonsusceptibility rates were 40, 98, and 16%, respectively. Plazomicin MICs ranged from 0.25 to 1 μg/ml. Tobramycin and plazomicin MICs correlated with gentamicin MICs (r= 0.75 and 0.57, respectively). Plazomicin exerted bactericidal activity against 17% (1× MIC) and 94% (4× MIC) of strains. All strains with AAC(6′)-Ib were tobramycin-resistant; 16% were nonsusceptible to amikacin. AAC(6′)-Ib combined with another AME was associated with higher gentamicin, tobramycin, and plazomicin MICs than AAC(6′)-Ib alone (P= 0.01, 0.0008, and 0.046, respectively). The presence of AAC(3)-IV in a strain was also associated with higher gentamicin, tobramycin, and plazomicin MICs (P= 0.0006,P< 0.0001, andP= 0.01, respectively). The combination of AAC(6′)-Ib and another AME, the presence of AAC(3)-IV, and the presence of APH(3′)-Ia were each associated with gentamicin resistance (P= 0.0002, 0.003, and 0.01, respectively). In conclusion, carbapenem-resistantK. pneumoniaestrains (including ST258 clones) exhibit highly diverse antimicrobial resistance genotypes and phenotypes. Plazomicin may offer a treatment option against strains resistant to other aminoglycosides. The development of molecular assays that predict antimicrobial responses among carbapenem-resistantK. pneumoniaestrains should be a research priority.

scholarly journals Evolution of Carbapenem-Resistant Serotype K1 Hypervirulent Klebsiella pneumoniae by Acquisition of blaVIM-1-Bearing Plasmid

2019 ◽  
Vol 63 (9) ◽  
Author(s):  
Ning Dong ◽  
Qiaoling Sun ◽  
Yonglu Huang ◽  
Lingbin Shu ◽  
Lianwei Ye ◽  
...  
Keyword(s):  
Klebsiella Pneumoniae ◽  
Genomic Analysis ◽  
Carbapenem Resistance ◽  
Sequence Type ◽  
Mosaic Structure ◽  
Multiple Gene ◽  
Content Type ◽  
Carbapenem Resistant ◽  
Simultaneous Expression

ABSTRACT We report the identification of a carbapenem-resistant, hypervirulent Klebsiella pneumoniae (hvKp) strain which produced the carbapenemase VIM-1. Genomic analysis showed that the strain belonged to sequence type ST23 and serotype K1, a major hvKp clone, and harbored three resistance-encoding plasmids. Among them, a blaVIM-1-bearing plasmid was found to possess a mosaic structure presumably generated by multiple gene mobilization events. This finding indicates that hvKp actively acquires mobile resistance-encoding elements, facilitating simultaneous expression of hypervirulence and carbapenem-resistance.

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