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 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 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 A Prolonged Outbreak of KPC-3-Producing Enterobacter cloacae and Klebsiella pneumoniae Driven by Multiple Mechanisms of Resistance Transmission at a Large Academic Burn Center

2016 ◽  
Vol 61 (2) ◽  
Author(s):  
Hajime Kanamori ◽  
Christian M. Parobek ◽  
Jonathan J. Juliano ◽  
David van Duin ◽  
Bruce A. Cairns ◽  
...  
Keyword(s):  
Klebsiella Pneumoniae ◽  
Molecular Mechanisms ◽  
Enterobacter Cloacae ◽  
The United States ◽  
Multidrug Resistant ◽  
Control Measures ◽  
Content Type ◽  
Burn Center ◽  
Infection Control Measures ◽  
Carbapenem Resistant

ABSTRACT Klebsiella pneumoniae carbapenemase (KPC)-producing Enterobacter cloacae has been recently recognized in the United States. Whole-genome sequencing (WGS) has become a useful tool for analysis of outbreaks and for determining transmission networks of multidrug-resistant organisms in health care settings, including carbapenem-resistant Enterobacteriaceae (CRE). We experienced a prolonged outbreak of CRE E. cloacae and K. pneumoniae over a 3-year period at a large academic burn center despite rigorous infection control measures. To understand the molecular mechanisms that sustained this outbreak, we investigated the CRE outbreak isolates by using WGS. Twenty-two clinical isolates of CRE, including E. cloacae (n = 15) and K. pneumoniae (n = 7), were sequenced and analyzed genetically. WGS revealed that this outbreak, which seemed epidemiologically unlinked, was in fact genetically linked over a prolonged period. Multiple mechanisms were found to account for the ongoing outbreak of KPC-3-producing E. cloacae and K. pneumoniae. This outbreak was primarily maintained by a clonal expansion of E. cloacae sequence type 114 (ST114) with distribution of multiple resistance determinants. Plasmid and transposon analyses suggested that the majority of bla KPC-3 was transmitted via an identical Tn4401b element on part of a common plasmid. WGS analysis demonstrated complex transmission dynamics within the burn center at levels of the strain and/or plasmid in association with a transposon, highlighting the versatility of KPC-producing Enterobacteriaceae in their ability to utilize multiple modes to resistance gene propagation.

scholarly journals First Report of Ceftazidime-Avibactam Resistance in a KPC-3-Expressing Klebsiella pneumoniae Isolate

2015 ◽  
Vol 59 (10) ◽  
pp. 6605-6607 ◽  
Author(s):  
Romney M. Humphries ◽  
Shangxin Yang ◽  
Peera Hemarajata ◽  
Kevin W. Ward ◽  
Janet A. Hindler ◽  
...  
Keyword(s):  
Klebsiella Pneumoniae ◽  
Prior Treatment ◽  
Content Type ◽  
First Report ◽  
Class A ◽  
Carbapenem Resistant ◽  
Lactamase Inhibitor ◽  
The U.S

ABSTRACTCeftazidime-avibactam is the first antimicrobial approved by the U.S. FDA for the treatment of carbapenem-resistantEnterobacteriaceae. Avibactam, a non-β-lactam β-lactamase inhibitor, inactivates class A serine carbapenemases, includingKlebsiella pneumoniaecarbapenemase (KPC). We report a KPC-producingK. pneumoniaeisolate resistant to ceftazidime-avibactam (MIC, 32/4 μg/ml) from a patient with no prior treatment with ceftazidime-avibactam.

scholarly journals Outbreak of Klebsiella pneumoniae Producing a New Carbapenem-Hydrolyzing Class A β-Lactamase, KPC-3, in a New York Medical Center

2004 ◽  
Vol 48 (12) ◽  
pp. 4793-4799 ◽  
Author(s):  
Neil Woodford ◽  
Philip M. Tierno ◽  
Katherine Young ◽  
Luke Tysall ◽  
Marie-France I. Palepou ◽  
...  
Keyword(s):  
New York ◽  
Klebsiella Pneumoniae ◽  
Medical Center ◽  
The United States ◽  
Outbreak Strain ◽  
Class A ◽  
Carbapenem Resistant ◽  
Novel Variant ◽  
Resistant Strains

ABSTRACT From April 2000 to April 2001, 24 patients in intensive care units at Tisch Hospital, New York, N.Y., were infected or colonized by carbapenem-resistant Klebsiella pneumoniae. Pulsed-field gel electrophoresis identified a predominant outbreak strain, but other resistant strains were also recovered. Three representatives of the outbreak strain from separate patients were studied in detail. All were resistant or had reduced susceptibility to imipenem, meropenem, ceftazidime, piperacillin-tazobactam, and gentamicin but remained fully susceptible to tetracycline. PCR amplified a bla KPC allele encoding a novel variant, KPC-3, with a His(272)→Tyr substitution not found in KPC-2; other carbapenemase genes were absent. In the outbreak strain, KPC-3 was encoded by a 75-kb plasmid, which was transferred in vitro by electroporation and conjugation. The isolates lacked the OmpK35 porin but expressed OmpK36, implying reduced permeability as a cofactor in resistance. This is the third KPC carbapenem-hydrolyzing β-lactamase variant to have been reported in members of the Enterobacteriaceae, with others reported from the East Coast of the United States. Although producers of these enzymes remain rare, the progress of this enzyme group merits monitoring.

scholarly journals Surveillance of Carbapenem-Resistant Klebsiella pneumoniae: Tracking Molecular Epidemiology and Outcomes through a Regional Network

2014 ◽  
Vol 58 (7) ◽  
pp. 4035-4041 ◽  
Author(s):  
David van Duin ◽  
Federico Perez ◽  
Susan D. Rudin ◽  
Eric Cober ◽  
Jennifer Hanrahan ◽  
...  
Keyword(s):  
Klebsiella Pneumoniae ◽  
Long Term Care ◽  
Carbapenem Resistance ◽  
The United States ◽  
Molecular Characteristics ◽  
Regional Network ◽  
Term Care ◽  
Content Type ◽  
Carbapenem Resistant

ABSTRACTCarbapenem resistance in Gram-negative bacteria is on the rise in the United States. A regional network was established to study microbiological and genetic determinants of clinical outcomes in hospitalized patients with carbapenem-resistant (CR)Klebsiella pneumoniaein a prospective, multicenter, observational study. To this end, predefined clinical characteristics and outcomes were recorded andK. pneumoniaeisolates were analyzed for strain typing and resistance mechanism determination. In a 14-month period, 251 patients were included. While most of the patients were admitted from long-term care settings, 28% of them were admitted from home. Hospitalizations were prolonged and complicated. Nonsusceptibility to colistin and tigecycline occurred in isolates from 7 and 45% of the patients, respectively. Most of the CRK. pneumoniaeisolates belonged to repetitive extragenic palindromic PCR (rep-PCR) types A and B (both sequence type 258) and carried eitherblaKPC-2(48%) orblaKPC-3(51%). One isolate tested positive forblaNDM-1, a sentinel discovery in this region. Important differences between strain types were noted; rep-PCR type B strains were associated withblaKPC-3(odds ratio [OR], 294; 95% confidence interval [CI], 58 to 2,552;P< 0.001), gentamicin nonsusceptibility (OR, 24; 95% CI, 8.39 to 79.38;P< 0.001), amikacin susceptibility (OR, 11.0; 95% CI, 3.21 to 42.42;P< 0.001), tigecycline nonsusceptibility (OR, 5.34; 95% CI, 1.30 to 36.41;P= 0.018), a shorter length of stay (OR, 0.98; 95% CI, 0.95 to 1.00;P= 0.043), and admission from a skilled-nursing facility (OR, 3.09; 95% CI, 1.26 to 8.08;P= 0.013). Our analysis shows that (i) CRK. pneumoniaeis seen primarily in the elderly long-term care population and that (ii) regional monitoring of CRK. pneumoniaereveals insights into molecular characteristics. This work highlights the crucial role of ongoing surveillance of carbapenem resistance determinants.

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 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 Plasmid-Mediated KPC-2 in a Klebsiella pneumoniae Isolate from China

2006 ◽  
Vol 51 (2) ◽  
pp. 763-765 ◽  
Author(s):  
Ze-Qing Wei ◽  
Xiao-Xing Du ◽  
Yun-Song Yu ◽  
Ping Shen ◽  
Ya-Gang Chen ◽  
...  
Keyword(s):  
United States ◽  
Klebsiella Pneumoniae ◽  
The United States ◽  
Resistant Isolate ◽  
Genetic Environment ◽  
Class A ◽  
Carbapenem Resistant

ABSTRACT A carbapenem-resistant isolate of Klebsiella pneumoniae producing class A carbapenemase KPC-2 was identified in Zhejiang, China. The KPC-2 gene was located on an approximately 60-kb plasmid in a genetic environment partially different from that of bla KPC-2 in the isolates from the United States and Colombia.

scholarly journals Multicenter Clinical and Molecular Epidemiological Analysis of Bacteremia Due to Carbapenem-Resistant Enterobacteriaceae (CRE) in the CRE Epicenter of the United States

2017 ◽  
Vol 61 (4) ◽  
Author(s):  
Michael J. Satlin ◽  
Liang Chen ◽  
Gopi Patel ◽  
Angela Gomez-Simmonds ◽  
Gregory Weston ◽  
...  
Keyword(s):  
New York ◽  
Empirical Therapy ◽  
Carbapenem Resistance ◽  
The United States ◽  
Resistance Mechanisms ◽  
Rapid Diagnostics ◽  
Multicenter Studies ◽  
Content Type ◽  
Medical Centers ◽  
Carbapenem Resistant

ABSTRACT Although the New York/New Jersey (NY/NJ) area is an epicenter for carbapenem-resistant Enterobacteriaceae (CRE), there are few multicenter studies of CRE from this region. We characterized patients with CRE bacteremia in 2013 at eight NY/NJ medical centers and determined the prevalence of carbapenem resistance among Enterobacteriaceae bloodstream isolates and CRE resistance mechanisms, genetic backgrounds, capsular types (cps), and antimicrobial susceptibilities. Of 121 patients with CRE bacteremia, 50% had cancer or had undergone transplantation. The prevalences of carbapenem resistance among Klebsiella pneumoniae, Enterobacter spp., and Escherichia coli bacteremias were 9.7%, 2.2%, and 0.1%, respectively. Ninety percent of CRE were K. pneumoniae and 92% produced K. pneumoniae carbapenemase (KPC-3, 48%; KPC-2, 44%). Two CRE produced NDM-1 and OXA-48 carbapenemases. Sequence type 258 (ST258) predominated among KPC-producing K. pneumoniae (KPC-Kp). The wzi154 allele, corresponding to cps-2, was present in 93% of KPC-3-Kp, whereas KPC-2-Kp had greater cps diversity. Ninety-nine percent of CRE were ceftazidime-avibactam (CAZ-AVI)-susceptible, although 42% of KPC-3-Kp had an CAZ-AVI MIC of ≥4/4 μg/ml. There was a median of 47 h from bacteremia onset until active antimicrobial therapy, 38% of patients had septic shock, and 49% died within 30 days. KPC-3-Kp bacteremia (adjusted odds ratio [aOR], 2.58; P = 0.045), cancer (aOR, 3.61, P = 0.01), and bacteremia onset in the intensive care unit (aOR, 3.79; P = 0.03) were independently associated with mortality. Active empirical therapy and combination therapy were not associated with survival. Despite a decade of experience with CRE, patients with CRE bacteremia have protracted delays in appropriate therapies and high mortality rates, highlighting the need for rapid diagnostics and evaluation of new therapeutics.

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