Searching for the Optimal #Treatment for Metallo- and Serine-β-Lactamase Producing #Enterobacteriaceae: #Aztreonam in Combination with #Ceftazidime-avibactam or #Meropenem-vaborbactam (AAC, abstract)

[Source: Antimicrobial Agents and Chemotherapy, full page: (LINK). Abstract, edited.]

Searching for the Optimal Treatment for Metallo- and Serine-β-Lactamase Producing Enterobacteriaceae: Aztreonam in Combination with Ceftazidime-avibactam or Meropenem-vaborbactam

M Biagi, T Wu, M Lee, S Patel, D Butler, E Wenzler

DOI: 10.1128/AAC.01426-19

 

ABSTRACT

Objective:

Metallo-β-lactamase (MBL)-producing Enterobacteriaceae, particularly those that co-harbor serine β-lactamases, are a serious emerging public health threat given their rapid dissemination and the limited number of treatment options. Pre-clinical and anecdotal clinical data support the use of aztreonam in combination with ceftazidime-avibactam against these pathogens, but other aztreonam-based combinations have not been explored. The objective of this study was to evaluate the in vitro activity and compare synergy between aztreonam in combination with ceftazidime-avibactam and meropenem-vaborbactam against serine and MBL-producing Enterobacteriaceae via time-kill analyses.

Methods:

8 clinical Enterobacteriaceae strains (4 Escherichia coli and 4 Klebsiella pneumoniae) co-producing NDM and at least one serine β-lactamase were used for all experiments. Drugs were tested alone, in dual β-lactam combinations, and in triple drug combinations against all strains.

Results:

All strains were resistant to ceftazidime-avibactam and meropenem-vaborbactam and 7/8 (87.5%) strains were resistant to aztreonam. Aztreonam combined with ceftazidime-avibactam was synergistic against all 7 aztreonam-resistant strains. Aztreonam combined with meropenem-vaborbactam was synergistic against all aztreonam-resistant strains with the exception of an OXA-232-producing K. pneumoniae strain. Neither triple combination was synergistic against the aztreonam-susceptible strain. Likewise, neither dual β-lactam combination was synergistic against any strain.

Conclusions:

These data suggest that aztreonam plus meropenem-vaborbactam has similar activity to aztreonam plus ceftazidime-avibactam against Enterobacteriaceae producing NDM and other non-OXA-48-like serine β-lactamases. Confirmation of these findings in future in vitro and in vivo models is warranted.

Copyright © 2019 American Society for Microbiology. All Rights Reserved.

Keywords: Antibiotics; Drugs Resistance; Beta-lactams; NDM; Aztreonam; Meropenem; Vaborbactam; Ceftazidime; Avibactam; Enterobacteriaceae.

——

#Ceftolozane – #tazobactam versus #meropenem for #treatment of #nosocomial #pneumonia (ASPECT-NP): a randomised, controlled, double-blind, phase 3, non-inferiority trial (Lancet Infect Dis., abstract)

[Source: The Lancet Infectious Diseases, full page: (LINK). Abstract, edited.]

Ceftolozane–tazobactam versus meropenem for treatment of nosocomial pneumonia (ASPECT-NP): a randomised, controlled, double-blind, phase 3, non-inferiority trial

Prof Marin H Kollef, MD, Martin Nováček, MD, Prof Ülo Kivistik, MD, Prof Álvaro Réa-Neto, MD, Prof Nobuaki Shime, MD, Prof Ignacio Martin-Loeches, MD, Prof Jean-François Timsit, MD, Prof Richard G Wunderink, MD, Christopher J Bruno, MD, Jennifer A Huntington, PharmD, Gina Lin, MS, Brian Yu, PharmD, Joan R Butterton, MD, Elizabeth G Rhee, MD

Published: September 25, 2019 / DOI: https://doi.org/10.1016/S1473-3099(19)30403-7

 

Summary

Background

Nosocomial pneumonia due to antimicrobial-resistant pathogens is associated with high mortality. We assessed the efficacy and safety of the combination antibacterial drug ceftolozane–tazobactam versus meropenem for treatment of Gram-negative nosocomial pneumonia.

Methods

We conducted a randomised, controlled, double-blind, non-inferiority trial at 263 hospitals in 34 countries. Eligible patients were aged 18 years or older, were undergoing mechanical ventilation, and had nosocomial pneumonia (either ventilator-associated pneumonia or ventilated hospital-acquired pneumonia). Patients were randomly assigned (1:1) with block randomisation (block size four), stratified by type of nosocomial pneumonia and age (<65 years vs ≥65 years), to receive either 3 g ceftolozane–tazobactam or 1 g meropenem intravenously every 8 h for 8–14 days. The primary endpoint was 28-day all-cause mortality (at a 10% non-inferiority margin). The key secondary endpoint was clinical response at the test-of-cure visit (7–14 days after the end of therapy; 12·5% non-inferiority margin). Both endpoints were assessed in the intention-to-treat population. Investigators, study staff, patients, and patients’ representatives were masked to treatment assignment. Safety was assessed in all randomly assigned patients who received study treatment. This trial was registered with ClinicalTrials.gov, NCT02070757.

Findings

Between Jan 16, 2015, and April 27, 2018, 726 patients were enrolled and randomly assigned, 362 to the ceftolozane–tazobactam group and 364 to the meropenem group. Overall, 519 (71%) patients had ventilator-associated pneumonia, 239 (33%) had Acute Physiology and Chronic Health Evaluation II scores of at least 20, and 668 (92%) were in the intensive care unit. At 28 days, 87 (24·0%) patients in the ceftolozane–tazobactam group and 92 (25·3%) in the meropenem group had died (weighted treatment difference 1·1% [95% CI −5·1 to 7·4]). At the test-of-cure visit 197 (54%) patients in the ceftolozane–tazobactam group and 194 (53%) in the meropenem group were clinically cured (weighted treatment difference 1·1% [95% CI −6·2 to 8·3]). Ceftolozane–tazobactam was thus non-inferior to meropenem in terms of both 28-day all-cause mortality and clinical cure at test of cure. Treatment-related adverse events occurred in 38 (11%) of 361 patients in the ceftolozane–tazobactam group and 27 (8%) of 359 in the meropenem group. Eight (2%) patients in the ceftolozane–tazobactam group and two (1%) in the meropenem group had serious treatment-related adverse events. There were no treatment-related deaths.

Interpretation

High-dose ceftolozane–tazobactam is an efficacious and well tolerated treatment for Gram-negative nosocomial pneumonia in mechanically ventilated patients, a high-risk, critically ill population.

Funding

Merck & Co.

Keywords: Antibiotics; Drugs Resistance; Pneumonia; ICU; Meropenem; Ceftolozane; Tazobactam.

——

Adjunctive #transferrin to reduce the emergence of #antibiotic #resistance in Gram-negative #bacteria (J Antimicrob Chemother., abstract)

[Source: Journal of Antimicrobial Chemotherapy, full page: (LINK). Abstract, edited.]

Adjunctive transferrin to reduce the emergence of antibiotic resistance in Gram-negative bacteria

Brian M Luna, Ksenia Ershova, Jun Yan, Amber Ulhaq, Travis B Nielsen, Sarah Hsieh, Paul Pantapalangkoor, Brian Vanscoy, Paul Ambrose, Sue Rudin, Kristine Hujer, Robert A Bonomo, Luis Actis, Eric P Skaar, Brad Spellberg

Journal of Antimicrobial Chemotherapy, dkz225, https://doi.org/10.1093/jac/dkz225

Published: 06 June 2019

 

Abstract

Background

New strategies are needed to slow the emergence of antibiotic resistance among bacterial pathogens. In particular, society is experiencing a crisis of antibiotic-resistant infections caused by Gram-negative bacterial pathogens and novel therapeutics are desperately needed to combat such diseases. Acquisition of iron from the host is a nearly universal requirement for microbial pathogens—including Gram-negative bacteria—to cause infection. We have previously reported that apo-transferrin (lacking iron) can inhibit the growth of Staphylococcus aureus in culture and diminish emergence of resistance to rifampicin.

Objectives

To define the potential of apo-transferrin to inhibit in vitro growth of Klebsiella pneumoniae and Acinetobacter baumannii, key Gram-negative pathogens, and to reduce emergence of resistance to antibiotics.

Methods

The efficacy of apo-transferrin alone or in combination with meropenem or ciprofloxacin against K. pneumoniae and A. baumannii clinical isolates was tested by MIC assay, time–kill assay and assays for the selection of resistant mutants.

Results

We confirmed that apo-transferrin had detectable MICs for all strains tested of both pathogens. Apo-transferrin mediated an additive antimicrobial effect for both antibiotics against multiple strains in time–kill assays. Finally, adding apo-transferrin to ciprofloxacin or meropenem reduced the emergence of resistant mutants during 20 day serial passaging of both species.

Conclusions

These results suggest that apo-transferrin may have promise to suppress the emergence of antibiotic-resistant mutants when treating infections caused by Gram-negative bacteria.

Topic: antibiotics – iron – antibiotic resistance, bacterial – ciprofloxacin – gram-negative bacteria – transferrin – meropenem – malnutrition-inflammation-cachexia syndrome

Issue Section: ORIGINAL RESEARCH

Keywords: Antibiotics; Drugs Resistance; Meropenem; Ciprofloxacin; Transferrin.

——

Potentiation of #betalactam #antibiotics and β-lactam/β-lactamase inhibitor combinations against #MDR and #XDR #Pseudomonas aeruginosa using non-ribosomal #tobramycin–cyclam conjugates (J Antimicrob Chemother., abstract)

[Source: Journal of Antimicrobial Chemotherapy, full page: (LINK). Abstract, edited.]

Potentiation of β-lactam antibiotics and β-lactam/β-lactamase inhibitor combinations against MDR and XDR Pseudomonas aeruginosa using non-ribosomal tobramycin–cyclam conjugates

Temilolu Idowu, Derek Ammeter, Gilbert Arthur, George G Zhanel, Frank Schweizer

Journal of Antimicrobial Chemotherapy, dkz228, https://doi.org/10.1093/jac/dkz228

Published: 28 May 2019

 

Abstract

Objectives

To develop a multifunctional adjuvant molecule that can rescue β-lactam antibiotics and β-lactam/β-lactamase inhibitor combinations from resistance in carbapenem-resistant Pseudomonas aeruginosa clinical isolates.

Methods

Preparation of adjuvant was guided by structure–activity relationships, following standard protocols. Susceptibility and chequerboard studies were assessed using serial 2-fold dilution assays. Toxicity was evaluated against porcine erythrocytes, human embryonic kidney (HEK293) cells and liver carcinoma (HepG2) cells via MTS assay. Preliminary in vivo efficacy was evaluated using a Galleria mellonella infection model.

Results

Conjugation of tobramycin and cyclam abrogates the ribosomal effects of tobramycin but confers a potent adjuvant property that restores full antibiotic activity of meropenem and aztreonam against carbapenem-resistant P. aeruginosa. Therapeutic levels of susceptibility, as determined by CLSI susceptibility breakpoints, were attained in several MDR clinical isolates, and time–kill assays revealed a synergistic dose-dependent pharmacodynamic relationship. A triple combination of the adjuvant with ceftazidime/avibactam (approved), aztreonam/avibactam (Phase III) and meropenem/avibactam enhances the efficacies of β-lactam/β-lactamase inhibitors against recalcitrant strains, suggesting rapid access of the combination to their periplasmic targets. The newly developed adjuvants, and their combinations, were non-haemolytic and non-cytotoxic, and preliminary in vivo evaluation in G. mellonella suggests therapeutic potential for the double and triple combinations.

Conclusions

Non-ribosomal tobramycin–cyclam conjugate mitigates the effect of OprD/OprF porin loss in P. aeruginosa and potentiates β-lactam/β-lactamase inhibitors against carbapenem-resistant clinical isolates, highlighting the complexity of resistance to β-lactam antibiotics. Our strategy presents an avenue to further preserve the therapeutic utility of β-lactam antibiotics.

Topic: antibiotics – pseudomonas aeruginosa – immunologic adjuvants – pharmaceutical adjuvants – aztreonam – ceftazidime – lactams – ribosomes – infection – tobramycin – meropenem – toxic effect – potentiation – avibactam – carbapenem resistance

Issue Section: ORIGINAL RESEARCH

© The Author(s) 2019. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For permissions, please email: journals.permissions@oup.com.

This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model (https://academic.oup.com/journals/pages/open_access/funder_policies/chorus/standard_publication_model)

Keywords: Antibiotics; Drugs Resistance; Carbapenem; Beta-lactams; Pseudomonas aeruginosa; Tobramycin; Aztreonam; Avibactam; Ceftazidime.

——

Reduced #ceftazidime and #ertapenem susceptibility due to production of #OXA-2 in #Klebsiella pneumoniae ST258 (J Antimicrob Chemother., abstract)

[Source: Journal of Antimicrobial Chemotherapy, full page: (LINK). Abstract, edited.]

Reduced ceftazidime and ertapenem susceptibility due to production of OXA-2 in Klebsiella pneumoniaeST258

Alina Iovleva, Roberta T Mettus, Christi L McElheny, Mustapha M Mustapha, Daria Van Tyne, Ryan K Shields, A William Pasculle, Vaughn S Cooper, Yohei Doi

Journal of Antimicrobial Chemotherapy, dkz183, https://doi.org/10.1093/jac/dkz183

Published: 24 May 2019

 

Abstract

Background

OXA-2 is a class D β-lactamase that confers resistance to penicillins, as well as narrow-spectrum cephalosporins. OXA-2 was recently reported to also possess carbapenem-hydrolysing activity. Here, we describe a KPC-2-encoding Klebsiella pneumoniae isolate that demonstrated reduced susceptibility to ceftazidime and ertapenem due to production of OXA-2.

Objectives

To elucidate the role of OXA-2 production in reduced ceftazidime and ertapenem susceptibility in a K. pneumoniae ST258 clinical isolate.

Methods

MICs were determined by the agar dilution method. WGS was conducted to identify and compare resistance genes between isolates. Expression of KPC-2 was quantified by quantitative RT–PCR and immunoblotting. OXA-2 was expressed in Escherichia coli TOP10, as well as in K. pneumoniae ATCC 13883, to define the relative contribution of OXA-2 in β-lactam resistance. Kinetic studies were conducted using purified OXA-2 enzyme.

Results

K. pneumoniae 1761 belonged to ST258 and carried both blaKPC-2 and blaOXA-2. However, expression of blaKPC-2 was substantially reduced due to an IS1294insertion in the promoter region. K. pneumoniae 1761, K. pneumoniae ATCC 13883 and E. coli TOP10 carrying blaOXA-2-harbouring plasmids showed reduced susceptibility to ertapenem and ceftazidime, but meropenem, imipenem and cefepime were unaffected. blaOXA-2 was carried on a 2910 bp partial class 1 integron containing aacA4-blaOXA-2-qacEΔ1-sul1 on an IncA/C2plasmid, which was not present in the earlier ST258 isolates possessing blaKPC-2 with intact promoters. Hydrolysis of ertapenem by OXA-2 was confirmed using purified enzyme.

Conclusions

Production of OXA-2 was associated with reduced ceftazidime and ertapenem susceptibility in a K. pneumoniae ST258 isolate.

Issue Section: ORIGINAL RESEARCH

© The Author(s) 2019. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For permissions, please email: journals.permissions@oup.com.

This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model (https://academic.oup.com/journals/pages/open_access/funder_policies/chorus/standard_publication_model)

Keywords: Antibiotics; Drugs Resistance; Beta-lactams; Carbapenem; Ceftazidime; Ertapenem; Meropenem; Imipenem; Cefepime.

——

Sub lethal levels of #platinum #nanoparticle cures #plasmid and in combination with #carbapenem, curtails carbapenem resistant #Escherichia coli (Sci Rep., abstract)

[Source: Scientific Reports, full page: (LINK). Abstract, edited.]

Article | OPEN | Published: 28 March 2019

Sub lethal levels of platinum nanoparticle cures plasmid and in combination with carbapenem, curtails carbapenem resistant Escherichia coli

Subhashree Bharathan, Niranjana Sri Sundaramoorthy, Harini Chandrasekaran, Gagana Rangappa, GaneshPrasad ArunKumar, Siva Bala Subramaniyan, Anbazhagan Veerappan & Saisubramanian Nagarajan

Scientific Reports, volume 9, Article number: 5305 (2019)

 

Abstract

Drug resistance traits are rapidly disseminated across bacteria by horizontal gene transfer, especially through plasmids. Plasmid curing agents that are active both in vitro and in vivo will resensitize Multi Drug Resistant (MDR) bacteria to antimicrobial agents. Pectin capped platinum nanoparticles (PtNPs) at sub MIC (20 µM) concentration was effective, in causing loss of Extended Spectrum Beta Lactamase (ESBL) harboring plasmid as evidenced by, absence of plasmid in agarose gel and by a concomitant (16–64 fold) drop in MIC for cell wall inhibitors ceftriaxone and meropenem, in carbapenem resistant Escherichia coli(CREC). Interestingly, the plasmid cured strain exhibited small colony morphology and displayed slower growth both in vitro and in vivo. Complementation of cured strain with plasmid from the wild type strain restored resistance towards meropenem and ceftriaxone. Relative to wild type, plasmid cured strain displayed 50% reduction in biofilm formation. Plasmid curing also occurred in vivo in infected zebrafish with curing efficiency of 17% for nanoparticle + meropenem treatment. PtNPs + meropenem reduced bioburden of CREC in infected zebrafish by 2.4 log CFU. Mechanistic studies revealed that nanoparticle interacted with cell surface and perturbed inner membrane integrity. PtNPs did not induce ROS, yet it caused plasmid DNA cleavage, as evidenced by gyrase inhibition assay. Our study for the first time reveals that PtNPs as plasmid curing agent can resensitize MDR bacteria to selective antimicrobial agents in vivo.

Keywords: Antibiotics; Drugs Resistance; Carbapenem; Ceftriaxone; Meropenem; E. Coli.

——

Whole genome assembly and functional portrait of #hypervirulent #XDR #NDM1 and #KPC2 co-producing #Klebsiella pneumoniae of capsular serotype K2 and ST86 (J Antimicrob Chemother., abstract)

[Source: Journal of Antimicrobial Chemotherapy, full page: (LINK). Abstract, edited.]

Whole genome assembly and functional portrait of hypervirulent extensively drug-resistant NDM-1 and KPC-2 co-producing Klebsiella pneumoniae of capsular serotype K2 and ST86

Yang Liu, Dan Long, Tian-Xin Xiang, Fang-Ling Du, Dan Dan Wei, La-Gen Wan, Qiong Deng, Xian-Wei Cao, Wei Zhang

Journal of Antimicrobial Chemotherapy, dkz023, https://doi.org/10.1093/jac/dkz023

Published: 06 March 2019

 

Abstract

Objectives

To characterize an emergent carbapenem-resistant hypervirulent Klebsiella pneumoniae (CR-hvKP) strain, NUHL30457, which co-produces NDM-1 and KPC-2 carbapenemases.

Methods

We performed WGS analysis on a clinical carbapenemase-producing hypervirulent K. pneumoniae (CP-hvKP) strain NUHL30457. Sequence data were analysed using comparative genomics and phylogenetics. WGS was used to perform MLST, capsular genotyping and identification of virulence and antimicrobial resistance genes. The virulence of NUHL30457 was analysed by serum killing assay, neutrophil phagocytosis and mouse lethality assay.

Results

The NUHL30457 strain was carbapenem resistant and belonged to ST86 and serotype K2. A significant increase in resistance to serum killing and antiphagocytosis was found in the NUHL30457 strain compared with the reference strain. The murine lethality assay showed an LD50 of 2.5 × 102 cfu for the NUHL30457 strain, indicating hypervirulence. WGS revealed that NUHL30457 has a single 5.3 Mb chromosome (57.53% G + C content) and four plasmids in the range 49.2–215.7 kb. The incompatibility group (Inc)N plasmid p30457-4 carried the blaNDM-1 and qnrS1 genes. The IncFII(K) plasmid p30457-3 also carried an array of resistance elements, including blaCTX-M-65, blaTEM-1 and blaKPC-2. The IncHI1/IncFIB plasmid p30457-1, which carried virulence genes, was identical to a pLVPK plasmid reported previously.

Conclusions

To the best of our knowledge, this is the first report to isolate an ST86 hvKP strain that co-produces NDM-1 and KPC-2 carbapenemase. Further investigation is required to reinforce our understanding of the epidemiology and virulence mechanisms of this clinically significant CP-hvKP.

Topic: plasmids – epidemiology – chromosomes – drug resistance, microbial – genes – genome – genomics – klebsiella pneumoniae – lethal dose 50 – neutrophils – phagocytosis – mice – virulence – genotype determination – beta-lactamase ndm-1 – phylogenetic analysis – killing – hypervirulent variant of klebsiella pneumoniae – serotype – synthetic cannabinoids – carbapenem resistance – whole genome sequencing

Issue Section: ORIGINAL RESEARCH

© The Author(s) 2019. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For permissions, please email: journals.permissions@oup.com.

This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model (https://academic.oup.com/journals/pages/open_access/funder_policies/chorus/standard_publication_model)

Keywords: Antibiotics; Drugs Resistance; Meropenem; Beta-lactams; NDM1; Klebsiella pneumoniae.

——