From #farm to #fork: identical #clones and Tn6674-like elements in #linezolid-resistant #Enterococcus faecalis from #food-producing #animals and #retail meat (J Antimicrob Chemother., abstract)

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

From farm to fork: identical clones and Tn6674-like elements in linezolid-resistant Enterococcus faecalis from food-producing animals and retail meat

Houyem Elghaieb, Ana P Tedim, Mohamed S Abbassi, Carla Novais, Bárbara Duarte, Abdennaceur Hassen, Luísa Peixe, Ana R Freitas

Journal of Antimicrobial Chemotherapy, dkz419, https://doi.org/10.1093/jac/dkz419

Published: 11 October 2019

 

Abstract

Objectives

Increasing numbers of linezolid-resistant Enterococcus carrying optrA are being reported across different niches worldwide. We aimed to characterize the first optrA-carrying Enterococcus faecalis obtained from food-producing animals and retail meat samples in Tunisia.

Methods

Seven optrA-carrying E. faecalis obtained from chicken faeces (n = 3, August 2017) and retail chicken meat (n = 4, August 2017) in Tunisia were analysed. Antimicrobial susceptibility was determined by disc diffusion, broth microdilution and Etest against 13 antibiotics, linezolid and tedizolid, respectively (EUCAST/CLSI). optrA stability (∼600 bacterial generations), transfer (filter mating) and location (S1-PFGE/hybridization) were characterized. WGS (Illumina-HiSeq) was done for four representatives that were analysed through in silico and genomic mapping tools.

Results

Four MDR clones carrying different virulence genes were identified in chicken faeces (ST476) and retail meat (the same ST476 clone plus ST21 and ST859) samples. MICs of linezolid and tedizolid were stably maintained at 8 and 1–2 mg/L, respectively. optrA was located in the same transferable chromosomal Tn6674-like element in ST476 and ST21 clones, similar to isolates from pigs in Malaysia and humans in China. ST859 carried a non-conjugative plasmid of ∼40 kb with an impB-fexA-optrA segment, similar to plasmids from pigs and humans in China.

Conclusions

The same chromosomal and transferable Tn6674-like element was identified in different E. faecalis clones from humans and animals. The finding of retail meat contaminated with the same linezolid-resistant E. faecalis strain obtained from a food-producing animal highlights the potential role of the food chain in the worrisome dissemination of optrA that can be stably maintained without selective pressure over generations.

Topic: antibiotics – enterococcus – plasmids – diffusion – chickens – china – chromosomes – clone cells – electrophoresis, gel, pulsed-field – enterococcus faecalis – feces – food – food chain – genes – genome – malaysia – meat – suidae – tunisia – virulence – linezolid – antimicrobial susceptibility – transfer technique – filters – mating – tedizolid – malnutrition-inflammation-cachexia syndrome – 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; Linezolid; Enterococci; Pigs; Poultry; Food Safety; Plasmids.

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Conjugative #delivery of #CRISPR-Cas9 for the selective #depletion of #antibiotic-resistant #enterococci (Antimicrob Agents Chemother., abstract)

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

Conjugative delivery of CRISPR-Cas9 for the selective depletion of antibiotic-resistant enterococci

Marinelle Rodrigues, Sara W. McBride, Karthik Hullahalli, Kelli L. Palmer, Breck A. Duerkop

DOI: 10.1128/AAC.01454-19

 

ABSTRACT

The innovation of new therapies to combat multidrug-resistant (MDR) bacteria is being outpaced by the continued rise of MDR bacterial infections. Of particular concern are hospital-acquired infections (HAIs) recalcitrant to antibiotic therapies. The Gram-positive intestinal pathobiont Enterococcus faecalis is associated with HAIs and some strains are MDR. Therefore, novel strategies to control E. faecalis populations are needed. We previously characterized an E. faecalis Type II CRISPR-Cas system and demonstrated its utility in the sequence-specific removal of antibiotic resistance determinants. Here we present work describing the adaption of this CRISPR-Cas system into a constitutively expressed module encoded on a pheromone-responsive conjugative plasmid that efficiently transfers to E. faecalis for the selective removal of antibiotic resistance genes. Using in vitro competition assays, we show that these CRISPR-Cas-encoding delivery plasmids, or CRISPR-Cas antimicrobials, can reduce the occurrence of antibiotic resistance in enterococcal populations in a sequence-specific manner. Furthermore, we demonstrate that deployment of CRISPR-Cas antimicrobials in the murine intestine reduces the occurrence of antibiotic-resistant E. faecalis by several orders of magnitude. Finally, we show that E. faecalis donor strains harboring CRISPR-Cas antimicrobials are immune to uptake of antibiotic resistance determinants in vivo. Our results demonstrate that conjugative delivery of CRISPR-Cas antimicrobials may be adaptable for future deployment from probiotic bacteria for exact targeting of defined MDR bacteria or for precision engineering of polymicrobial communities in the mammalian intestine.

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

Keywords: Antibiotics; Drugs Resistance; Enterococcus faecalis; CRISPR; Animal models.

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In vitro #bactericidal activity of #amoxicillin combined with different #cephalosporins against #endocarditis-associated #Enterococcus faecalis clinical isolates (J Antimicrob Chemother., abstract)

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

In vitro bactericidal activity of amoxicillin combined with different cephalosporins against endocarditis-associated Enterococcus faecalis clinical isolates

Nathan Peiffer-Smadja, Elena Guillotel, David Luque-Paz, Naouale Maataoui, F-Xavier Lescure, Vincent Cattoir

Journal of Antimicrobial Chemotherapy, dkz388, https://doi.org/10.1093/jac/dkz388

Published: 08 September 2019

 

Abstract

Background

The combination of amoxicillin with cefazolin could be an interesting regimen for the empirical therapy of severe infective endocarditis, but its activity against enterococci is unknown.

Objectives

To evaluate in vitro the bactericidal activity of the combination of amoxicillin with different cephalosporins including cefazolin.

Methods

Combinations of amoxicillin (at MIC × ¼) with cefazolin, cefotaxime, ceftriaxone, cefepime, ceftaroline or ceftobiprole (at the mean free plasma concentration) were studied using time–kill experiments for 10 endocarditis-associated Enterococcus faecalis strains and 2 reference strains.

Results

The combinations amoxicillin/cefazolin, amoxicillin/cefotaxime, amoxicillin/ceftriaxone and amoxicillin/cefepime were synergistic at 12 and 24 h against 12/12 strains and amoxicillin/ceftobiprole and amoxicillin/ceftaroline against 10/12 strains. The combination amoxicillin/cefepime was bactericidal at 24 h against 9/12 strains, the combination amoxicillin/cefazolin against 8/12 strains, the combinations amoxicillin/ceftaroline, amoxicillin/cefotaxime and amoxicillin/ceftobiprole against 7/12 strains and the combination amoxicillin/ceftriaxone against 6/12 strains.

Conclusions

The combination amoxicillin/cefazolin is as synergistic and bactericidal in vitro as amoxicillin/cefotaxime or amoxicillin/ceftriaxone against E. faecalis.

Issue Section: ORIGINAL RESEARCH

Keywords: Antibiotics; Amoxicillin; Cephalosporins; Endocarditis; Enterococcus faecalis.

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Therapeutic Effects of Intravitreously Administered #Bacteriophage in a Mouse Model of #Endophthalmitis Caused by #Vancomycin-Sensitive or -Resistant #Enterococcus faecalis (Antimicrob Agents Chemother., abstract)

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

Therapeutic Effects of Intravitreously Administered Bacteriophage in a Mouse Model of Endophthalmitis Caused by Vancomycin-Sensitive or -Resistant Enterococcus faecalis

Tatsuma Kishimoto, Waka Ishida, Ken Fukuda, Isana Nakajima, Takashi Suzuki, Jumpei Uchiyama, Shigenobu Matsuzaki, Daisuke Todokoro, Masanori Daibata, Atsuki Fukushima

DOI: 10.1128/AAC.01088-19

 

ABSTRACT

Endophthalmitis due to infection with Enterococcus spp. progresses rapidly and often results in substantial and irreversible vision loss. Given that the frequency of this condition caused by vancomycin-resistant Enterococcus faecalis has been increasing, the development of novel therapeutics is urgently required. We have now demonstrated the therapeutic potential of bacteriophage ΦEF24C-P2 in a mouse model of endophthalmitis caused by vancomycin-sensitive (EF24) or vancomycin-resistant (VRE2) strains of E. faecalis. Phage ΦEF24C-P2 induced rapid and pronounced bacterial lysis in turbidity reduction assays with EF24, VRE2, and clinical isolates derived from patients with E. faecalis–related postoperative endophthalmitis. Endophthalmitis was induced in mice by injection of EF24 or VRE2 (1 × 104cells) into the vitreous. The number of viable bacteria in the eye increased to >1 × 107 colony forming units and neutrophil infiltration into the eye was detected as an increase in myeloperoxidase activity at 24 h after infection. A clinical score based on loss of visibility of the fundus as well as the number of viable bacteria and the level of myeloperoxidase activity in the eye were all significantly decreased by intravitreous injection of ΦEF24C-P2 6 h after injection of EF24 or VRE2. Whereas histopathologic analysis revealed massive infiltration of inflammatory cells and retinal detachment in vehicle-treated eyes, the number of these cells was greatly reduced and retinal structural integrity was preserved in phage-treated eyes. Our results thus suggest that intravitreous phage therapy is a potential treatment for endophthalmitis caused by vancomycin-sensitive or -resistant strains of E. faecalis.

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

Keywords: Antibiotics; Drugs Resistance; Vancomycin; Enterococcus faecalis; Endophthalmitis; Bacteriophages.

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Impact of #antibiotic #treatment and host innate immune pressure on #enterococcal adaptation in the #human #bloodstream (Sci Transl Med., abstract)

[Source: Science Translational Medicine, full page: (LINK). Abstract, edited.]

Impact of antibiotic treatment and host innate immune pressure on enterococcal adaptation in the human bloodstream

Daria Van Tyne 1,2,3, Abigail L. Manson 3, Mark M. Huycke 4,  John Karanicolas 5,  Ashlee M. Earl 3 and Michael S. Gilmore 1,2,3,*

{1} Department of Ophthalmology and Department of Microbiology, Harvard Medical School, Boston, MA 02114, USA. {2} Department of Ophthalmology, Massachusetts Eye and Ear Infirmary, Boston, MA 02114, USA. {3} Infectious Disease and Microbiome Program, Broad Institute, Cambridge, MA 02142, USA. {4} Department of Internal Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA. {5} Program in Molecular Therapeutics, Fox Chase Cancer Center, Philadelphia, PA 19111, USA.

*Corresponding author. Email: michael_gilmore@meei.harvard.edu

Science Translational Medicine  10 Apr 2019: Vol. 11, Issue 487, eaat8418 / DOI: 10.1126/scitranslmed.aat8418

 

Friend turned foe

Enterococci are commensal bacteria found in the gut of most humans. Strains have arisen that are able to survive disinfection protocols in hospitals and that are resistant to antibiotics, resulting in the spread of this bacterium from patient to patient. To elucidate how enterococci have made this adaptation, Van Tyne et al. analyzed the genomes of enterococcal strains from an early outbreak of bloodstream infection in a hospital ward in the mid-1980s. They report the genetic changes that enabled the enterococci causing the human bloodstream infection to survive elimination by the host innate immune system and antibiotic therapy.

 

Abstract

Multidrug-resistant enterococcal strains emerged in the early 1980s and are now among the leading causes of drug-resistant bacterial infection worldwide. We used functional genomics to study an early bacterial outbreak in patients in a Wisconsin hospital between 1984 and 1988 that was caused by multidrug-resistant Enterococcus faecalis. The goal was to determine how a clonal lineage of E. faecalis became adapted to growth and survival in the human bloodstream. Genome sequence analysis revealed a progression of increasingly fixed mutations and repeated independent occurrences of mutations in a relatively small set of genes. Repeated independent mutations suggested selection within the host during the course of infection in response to pressures such as host immunity and antibiotic treatment. We observed repeated independent mutations in a small number of loci, including a little studied polysaccharide utilization pathway and the cydABDC locus. Functional studies showed that mutating these loci rendered E. faecalis better able to withstand antibiotic pressure and innate immune defenses in the human bloodstream. We also observed a shift in mutation pattern that corresponded to the introduction of carbapenem antibiotics in 1987. This work identifies pathways that allow enterococci to survive the transition from the human gut into the bloodstream, enabling them to cause severe bacteremia associated with high mortality.

Copyright © 2019 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works
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This is an article distributed under the terms of the Science Journals Default License.

Keywords: Antibiotics; Drugs Resistance; Carbapenem; Enterococcus faecalis.

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