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.

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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.

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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.

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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.

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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.

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#Geographical and temporal #variation in the #frequency and #antimicrobial susceptibility of #bacteria isolated from patients hospitalized with bacterial #pneumonia: results from 20 years of the #SENTRY… (J Antimicrob Chemother., abstract)

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

Geographical and temporal variation in the frequency and antimicrobial susceptibility of bacteria isolated from patients hospitalized with bacterial pneumonia: results from 20 years of the SENTRY Antimicrobial Surveillance Program (1997–2016)

Helio S Sader, Mariana Castanheira, S J Ryan, Arends Herman Goossens, Robert K Flamm

Journal of Antimicrobial Chemotherapy, dkz074, https://doi.org/10.1093/jac/dkz074

Published:  06 March 2019

 

Abstract

Background

The SENTRY Antimicrobial Surveillance Program monitors the frequency of occurrence and antimicrobial susceptibility of organisms from various infection types worldwide.

Methods

A total of 102 995 bacterial isolates were consecutively collected (one per patient) in 1997–2016 from 258 medical centres in North America (n = 44 999; 113 centres), Europe (n = 30 988; 61 centres from 22 nations), the Asia-Pacific region (APAC; n = 16 503; 67 centres from 12 nations) and Latin America (n = 10 505; 17 centres from 7 nations). Organisms were isolated from respiratory tract specimens and tested for susceptibility by broth microdilution methods in a central laboratory.

Results

Staphylococcus aureus (n = 24 351) and Pseudomonas aeruginosa (n = 22 279) were the most common organisms overall. Klebsiella spp. (n = 10 565) ranked third in North America, Europe and APAC. The proportion of Gram-negatives increased from 70.0%–74.7% to 80.9%–82.6% in Europe, APAC and Latin America, and remained stable (65.5%–66.1%) in North America. Methicillin resistance rates decreased substantially in all four regions from 2005–06 to 2015–16 among S. aureus isolates. P. aeruginosa susceptibility to meropenem decreased overall in the initial years, but increased in the last years of the investigation. Among Klebsiella spp. isolates, susceptibility to ceftriaxone/meropenem decreased from 85.9%/99.3% to 58.6%/85.8% in Europe and from 91.8%/99.5% to 81.6%/93.9% in APAC during the study period.

Conclusions

Rank order and susceptibility rates varied widely by geographical region and over time. The occurrence of some resistance phenotypes increased, though others decreased over the 20 years of the SENTRY Antimicrobial Surveillance Program.

Topic:  phenotype – pseudomonas aeruginosa – ceftriaxone – staphylococcus aureus – bacterial pneumonia – asia – geographic area – inpatients – klebsiella – latin america – respiratory system – infection – bacteria – meropenem – antimicrobials – antimicrobial susceptibility – surveillance program

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; Ceftriaxone; MRSA; Klebsiella pneumoniae; Pseudomonas aeruginosa; Pneumonia.

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#WGS #analysis of #MDR #serotype 15A #Streptococcus pneumoniae in #Japan and the emergence of a highly resistant serotype 15A-ST9084 clone (Antimicrob Agents Chemother., abstract)

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

Whole-genome sequencing analysis of multidrug-resistant serotype 15A Streptococcus pneumoniae in Japan and the emergence of a highly resistant serotype 15A-ST9084 clone

Satoshi Nakano, Takao Fujisawa, Yutaka Ito, Bin Chang, Yasufumi Matsumura, Masaki Yamamoto, Shigeru Suga, Makoto Ohnishi, Miki Nagao

DOI: 10.1128/AAC.02579-18

 

ABSTRACT

Since the introduction of pneumococcal conjugate vaccines, an increase in the incidence of disease attributable to serotype 15A-ST63 pneumococci has been observed in many regions worldwide. We conducted a nationwide pediatric pneumococcal infection surveillance study between 2012 and 2014 in Japan. In the surveillance study, we detected multidrug-resistant serotype 15A-CC63 strains (resistant to macrolides, penicillin, cefotaxime and meropenem); in this study, we analyzed these resistant isolates to determine the dynamics and mechanism of resistance using whole-genome sequencing. In most of the penicillin-, cefotaxime- and meropenem-resistant strains, recombination occurred in the pbp2x region resulting in the acquisition of additional cefotaxime resistance to penicillin and meropenem. In the multidrug-resistant serotype 15A-CC63 strains, we identified a specific clone with ST9084, and all of the isolates were recovered from Yamaguchi prefecture in Japan. All of the serotype 15A-ST9084 isolates had a novel pbp2x-43 that was inserted by recombination events. The conserved amino acid motif profiles of pbp1a, pbp2b and pbp2x of the strains were identical to those in serotype 19A-ST320. A Bayesian analysis-based date estimation suggested that this clone emerged in approximately 2002 before the introduction of PCV in Japan. This clone should be monitored because serotype 15A is not contained in the currently used PCV13 and it was resistance to beta-lactams, which are often use in a clinical setting.

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

Keywords: Antibiotics; Drugs Resistance; Beta-lactams; Penicillin; Cefotaxime; Meropenem; S. pneumoniae; Japan.

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