Combination of #Azithromycin and #Gentamicin for Efficient #Treatment of #Pseudomonas aeruginosa Infections (J Infect Dis., abstract)

[Source: Journal of Infectious Diseases, full page. (LINK). Abstract, edited.]

Combination of Azithromycin and Gentamicin for Efficient Treatment of Pseudomonas aeruginosa Infections

Huan Ren, Yiwei Liu, Jingyi Zhou, Yuqing Long, Chang Liu, Bin Xia, Jing Shi, Zheng Fan,Yuying Liang, Shuiping Chen, Jun Xu, Penghua Wang, Yanhong Zhang, Guangbo Zhu,Huimin Liu, Yongxin Jin, Fang Bai, Zhihui Cheng, Shouguang Jin, Weihui Wu

The Journal of Infectious Diseases, jiz341, https://doi.org/10.1093/infdis/jiz341

Published: 16 August 2019

 

Abstract

Background

Trans-translation is a ribosome rescue system that plays an important role in bacterial tolerance to environmental stresses. It is absent in animals, making it a potential treatment target. However, its role in antibiotic tolerance in Pseudomonas aeruginosa remains unknown.

Methods

The role and activity of trans-translation during antibiotic treatment were examined with a trans-translation–deficient strain and a genetically modified trans-translation component gene, respectively. In vitro assays and murine infection models were used to examine the effects of suppression of trans-translation.

Results

We found that the trans-translation system plays an essential role in P. aeruginosa tolerance to azithromycin and multiple aminoglycoside antibiotics. We further demonstrated that gentamicin could suppress the azithromycin-induced activation of trans-translation. Compared with each antibiotic individually, gentamicin and azithromycin combined increased the killing efficacy against planktonic and biofilm-associated P. aeruginosa cells, including a reference strain PA14 and its isogenic carbapenem-resistance oprD mutant, the mucoid strain FRD1, and multiple clinical isolates. Furthermore, the gentamicin-azithromycin resulted in improved bacterial clearance in murine acute pneumonia, biofilm implant, and cutaneous abscess infection models.

Conclusions

Combination treatment with gentamicin and azithromycin is a promising strategy in combating P. aeruginosa infections.

Pseudomonas aeruginosa, trans-translation, azithromycin, antibiotic combination

Topic: antibiotics – pseudomonas aeruginosa – gentamicin sulfate (usp) – azithromycin – biofilms – gentamicins – infection – killing

Issue Section: Major Article

© The Author(s) 2019. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: 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; Aminoglycosides; Gentamicin; Azithromycin; Pseudomonas aeruginosa; Biofilm.

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#Resistance and hetero-resistance to #colistin in #Pseudomonas aeruginosa isolates from Wenzhou, #China (Antimicrob Agents Chemother., abstract)

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

Resistance and hetero-resistance to colistin in Pseudomonas aeruginosa isolates from Wenzhou, China

Jie Lin, Chunquan Xu, Renchi Fang, Jianming Cao, Xiucai Zhang, Yajie Zhao, Guofeng Dong, Yao Sun, Tieli Zhou

DOI: 10.1128/AAC.00556-19

 

ABSTRACT

Objectives:

To investigate the mechanisms of colistin resistance and hetero-resistance in Pseudomonas aeruginosa clinical isolates.

Methods:

Colistin resistance was determined by broth microdilution method. Colistin hetero-resistance was evaluated by population analysis profiles (PAPs). Time-kill assays were also conducted. Polymerase chain reaction (PCR) sequencing was performed to detect the resistance genes among (hetero-)resistant isolates, and quantitative real-time PCR (qRT-PCR) was performed to determine their expression levels. Pulsed field gel electrophoresis (PFGE) and multilocus sequence typing (MLST) were analyzed. Lipid A characteristic were determined via MALDI-TOF MS.

Results:

Two resistant isolates and nine hetero-resistant isolates were selected respectively in this study. Mutations in PmrB were detected in two resistant isolates. In hetero-resistant isolates, eight of nine hetero-resistant isolates had non-synonymous PmrB mutations, and two isolates, including one with PmrB mutation, had PhoQ alterations. Correspondingly, the expression levels of pmrA or phoP were up-regulated in PmrB- or PhoQ-mutated isolates. One isolate also found alterations in ParRS and CprRS. The transcript levels of pmrH gene were observed to increase across all investigated isolates. MALDI-TOF MS showed additional 4-amino-4-deoxy-L-arabinose (L-Ara4N) moieties in lipid A profiles in (hetero-)resistant isolates.

Conclusion:

In conclusion, both colistin resistance and hetero-resistance in P. aeruginosa in this study were mainly involved by alterations of the PmrAB regulatory system. There was strong association between mutations in specific genetic loci lipid A synthesis and regulating modifications to lipid A. The transition of colistin hetero-resistance to resistance should be concerned in future clinical surveillance.

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

Keywords: Antibiotics; Drugs Resistance; Colistin; Pseudomonas aeruginosa; China.

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Activity of #cefepime / #zidebactam (WCK 5222) against #Enterobacteriaceae, #Pseudomonas aeruginosa and #Acinetobacter baumannii endemic to #NYC #medical centres (J Antimicrob Chemother., abstract)

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

Activity of cefepime/zidebactam (WCK 5222) against Enterobacteriaceae, Pseudomonas aeruginosa and Acinetobacter baumannii endemic to New York City medical centres

Zeb Khan, Alejandro Iregui, David Landman, John Quale

Journal of Antimicrobial Chemotherapy, dkz294, https://doi.org/10.1093/jac/dkz294

Published: 11 July 2019

 

Abstract

Background

The combination of cefepime and zidebactam (WCK5222), a novel β-lactam enhancer, has demonstrated activity against a wide variety of Gram-negative pathogens and is currently under clinical evaluation.

Objectives

To examine the activity of cefepime/zidebactam against: (i) a contemporary collection of Gram-negative isolates from New York City; (ii) a collection of carbapenem-resistant clinical isolates; and (iii) a collection of isolates with characterized resistance mechanisms.

Methods

Susceptibility tests were performed using broth microdilution for cefepime, zidebactam and cefepime/zidebactam (1:1).

Results

More than 99% of a contemporary collection of Escherichia coli, Klebsiella pneumoniae and Enterobacter spp. had cefepime/zidebactam MICs ≤2 mg/L, the susceptibility breakpoint for cefepime. For K. pneumoniae, the acquisition of blaKPC resulted in increased MICs, although MICs remained ≤2 mg/L for 90% of KPC-possessing isolates. Overall for Pseudomonas aeruginosa, 98% of isolates had MICs ≤8 mg/L and MICs were affected by increased expression of ampC. For carbapenem-resistant P. aeruginosa, 78% of isolates had cefepime/zidebactam MICs ≤8 mg/L. The activity of cefepime/zidebactam against Acinetobacter baumannii was lower, with 85% of all isolates and 34% of carbapenem-resistant isolates with MICs ≤8 mg/L (cefepime interpretative criteria).

Conclusions

Cefepime/zidebactam demonstrated excellent activity against Enterobacteriaceae and P. aeruginosa, although activity was reduced in carbapenem-non-susceptible isolates. The activity against A. baumannii was reduced and studies examining the therapeutic efficacy in strains with high cefepime/zidebactam MICs are warranted.

Topic:  pseudomonas aeruginosa – cefepime – enterobacter – enterobacteriaceae – new york city – acinetobacter baumannii – bacterial carbapenemase resistance blakpc gene – malnutrition-inflammation-cachexia syndrome – 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; Enterobacteriaceae; Pseudomonas aeruginosa; Acinetobacter baumannii; Cefepine; Zidebactam; USA; NYC.

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#Mortality dynamics of #Pseudomonas aeruginosa #bloodstream #infections and the influence of defective OprD on mortality: prospective observational study (J Antimicrob Chemother., abstract)

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

Mortality dynamics of Pseudomonas aeruginosabloodstream infections and the influence of defective OprD on mortality: prospective observational study

Eun-Jeong Yoon, Dokyun Kim, Hyukmin Lee, Hye Sun Lee, Jeong Hwan Shin, Yoon Soo Park, Young Ah Kim, Jong Hee Shin, Kyeong Seob Shin, Young UhSeok Hoon Jeong

Journal of Antimicrobial Chemotherapy, dkz245, https://doi.org/10.1093/jac/dkz245

Published: 24 June 2019

 

Abstract

Background

To assess the mortality dynamics of patients with Pseudomonas aeruginosabloodstream infections (BSIs) and the influence of OprD deficiencies of the microorganism on early mortality.

Methods

A prospective multicentre observational study was conducted with 120 patients with P. aeruginosa BSIs occurring between May 2016 and April 2017 in six general hospitals in South Korea. PCR and sequencing were carried out to identify the alterations in oprD and the presence of virulence factors. Cox regression was used to estimate the risk factors for mortality at each timepoint and Kaplan–Meier survival analyses were performed to determine the mortality dynamics.

Results

During the 6 week follow-up, 10.8% (13/120) of the patients with P. aeruginosa BSIs died in 2 weeks, 14.2% (17/120) in 4 weeks and 20.0% (24/120) in 6 weeks, revealing a steep decrease in cumulative survival between the fourth and sixth weeks. ICU admission and SOFA score were risk factors for mortality in any weeks after BSI onset and causative OprD-defective P. aeruginosa had a risk tendency for mortality within 6 weeks. Among the 120 P. aeruginosa blood isolates, 14 were XDR, nine produced either IMP-6 or VIM-2 MBL, and 21 had OprD deficiency.

Conclusions

BSIs caused by OprD-defective P. aeruginosa resulted in a 2-fold higher 6 week mortality rate (33.3%) than that of BSIs caused by OprD-intact P. aeruginosa(17.2%), likely due to the decreased susceptibility to carbapenems and bacterial persistence in clinical settings.

Topic: pseudomonas aeruginosa – carbapenem – follow-up – mortality  – bloodstream infections – sequential organ failure assessment scores

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; Pseudomonas aeruginosa; Bacteremia.

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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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#Ceftazidime – #Avibactam in Combination With #Fosfomycin: A Novel #Therapeutic Strategy Against #MDR #Pseudomonas aeruginosa (J Infect Dis., abstract)

[Source: Journal of Infectious Diseases, full page: (LINK). Abstract, edited.]

Ceftazidime-Avibactam in Combination With Fosfomycin: A Novel Therapeutic Strategy Against Multidrug-Resistant Pseudomonas aeruginosa

Krisztina M Papp-Wallace, Elise T Zeiser, Scott A Becka, Steven Park, Brigid M Wilson, Marisa L Winkler, Roshan D’Souza, Indresh Singh, Granger Sutton, Derrick E Fouts, Liang Chen, Barry N Kreiswirth, Evelyn J Ellis-Grosse, George L Drusano, David S Perlin, Robert A Bonomo

The Journal of Infectious Diseases, jiz149, https://doi.org/10.1093/infdis/jiz149

Published: 17 May 2019

 

Abstract

Previously, by targeting penicillin-binding protein 3, Pseudomonas-derived cephalosporinase (PDC), and MurA with ceftazidime-avibactam-fosfomycin, antimicrobial susceptibility was restored among multidrug-resistant (MDR) Pseudomonas aeruginosa. Herein, ceftazidime-avibactam-fosfomycin combination therapy against MDR P. aeruginosa clinical isolate CL232 was further evaluated. Checkerboard susceptibility analysis revealed synergy between ceftazidime-avibactam and fosfomycin. Accordingly, the resistance elements present and expressed in P. aeruginosa were analyzed using whole-genome sequencing and transcriptome profiling. Mutations in genes that are known to contribute to β-lactam resistance were identified. Moreover, expression of blaPDC, the mexAB-oprM efflux pump, and murA were upregulated. When fosfomycin was administered alone, the frequency of mutations conferring resistance was high; however, coadministration of fosfomycin with ceftazidime-avibactam yielded a lower frequency of resistance mutations. In a murine infection model using a high bacterial burden, ceftazidime-avibactam-fosfomycin significantly reduced the P. aeruginosa colony-forming units (CFUs), by approximately 2 and 5 logs, compared with stasis and in the vehicle-treated control, respectively. Administration of ceftazidime-avibactam and fosfomycin separately significantly increased CFUs, by approximately 3 logs and 1 log, respectively, compared with the number at stasis, and only reduced CFUs by approximately 1 log and 2 logs, respectively, compared with the number in the vehicle-treated control. Thus, the combination of ceftazidime-avibactam-fosfomycin was superior to either drug alone. By employing a “mechanism-based approach” to combination chemotherapy, we show that ceftazidime-avibactam-fosfomycin has the potential to offer infected patients with high bacterial burdens a therapeutic hope against infection with MDR P. aeruginosa that lack metallo-β-lactamases.

Pseudomonas aeruginosa, β-lactams, fosfomycin, combination therapy

Topic:  pseudomonas aeruginosa – ceftazidime – fosfomycin – lactams – infection – mice – avibactam – avibactam/ceftazidime

Issue Section: Major Article

Keywords: Antibiotics; Drugs Resistance; Pseudomonas aeruginosa; Avibactam; Ceftazidime; Fosfomycin.

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Activity of # imipenem / #relebactam against #MDR #Pseudomonas aeruginosa in #Europe: SMART 2015–17 (J Antimicrob Chemother., abstract)

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

Activity of imipenem/relebactam against MDR Pseudomonas aeruginosa in Europe: SMART 2015–17

Sibylle H Lob, James A Karlowsky, Katherine Young, Mary R Motyl, Stephen Hawser, Nimmi D Kothari, Melinda E Gueny, Daniel F Sahm

Journal of Antimicrobial Chemotherapy, dkz191, https://doi.org/10.1093/jac/dkz191

Published: 13 May 2019

 

Abstract

Objectives

Relebactam is a diazabicyclooctane non-β-lactam inhibitor of Ambler class A and C β-lactamases that is in clinical development in combination with imipenem/cilastatin. The current study evaluated the in vitro activity of imipenem/relebactam against 5447 isolates of Pseudomonas aeruginosasubmitted to the SMART global surveillance programme in 2015–17 by 67 clinical laboratories in 22 European countries.

Methods

MICs were determined using the CLSI broth microdilution reference method (Eleventh Edition: M07, 2018). Relebactam was tested at a fixed concentration of 4 mg/L in combination with doubling dilutions of imipenem. MICs were interpreted using EUCAST clinical breakpoints (version 8.1); imipenem breakpoints were applied to imipenem/relebactam.

Results

Rates of susceptibility to imipenem and imipenem/relebactam (MIC ≤4 mg/L) were 69.4% and 92.4%, respectively, for all isolates of P. aeruginosa. Over one-third of all isolates (34.9%, 1902/5447) were MDR; lower respiratory tract isolates (38.3%, 1327/3461) were more frequently MDR than were intraabdominal (28.5%, 355/1245) or urinary tract (29.7%, 212/714) isolates. Of all MDR isolates, 78.2% were susceptible to imipenem/relebactam, a rate that was 50–77 percentage points higher than the rate of susceptibility to imipenem or any other β-lactam tested; rates of susceptibility to imipenem/relebactam were similar for MDR isolates from lower respiratory tract (77.8% susceptible), intraabdominal (80.3%) and urinary tract (76.4%) infections. Overall, relebactam restored imipenem susceptibility to 75.2% (1254/1668) of imipenem-non-susceptible isolates of P. aeruginosa and to 69.6% (947/1361) of imipenem-non-susceptible isolates with an MDR phenotype.

Conclusions

Relebactam restored in vitro susceptibility to imipenem for most imipenem-non-susceptible and MDR clinical isolates of P. aeruginosa from European patients.

Topic: phenotype – pseudomonas aeruginosa – imipenem – lactams – respiratory system – urinary tract – infection

Issue Section: ORIGINAL RESEARCH

Keywords: Antibiotics; Drugs Resistance; Pseudomonas aeruginosa; Relebactam; Imipenem; European Region.

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