A novel #plasmid-encoded #mcr-4.3 gene in a #colistin-resistant #Acinetobacter baumannii clinical strain (J Antimicrob Chemother., abstract)

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

A novel plasmid-encoded mcr-4.3 gene in a colistin-resistant Acinetobacter baumannii clinical strain

Natacha Martins-Sorenson, Erik Snesrud, Danilo Elias Xavier, Luciana Camila Cacci, Anthony T Iavarone, Patrick McGann, Lee W Riley, Beatriz Meurer Moreira

Journal of Antimicrobial Chemotherapy, dkz413, https://doi.org/10.1093/jac/dkz413

Published: 03 October 2019




To identify the molecular mechanism of colistin resistance in an MDR Acinetobacter baumannii clinical strain isolated in 2008 from a meningitis case in Brazil.


Long- and short-read WGS was used to identify colistin resistance genes in A. baumannii strain 597A with a colistin MIC of 64 mg/L. MS was used to analyse lipid A content. mcr was cloned into pET-26b (+) and transformed into Escherichia coli BL21(λDE3)pLysS for analysis.


A novel plasmid (pAb-MCR4.3) harbouring mcr-4.3 within a Tn3-like transposon was identified. The A. baumannii 597A lipid A MS spectra showed a main molecular ion peak at m/z = 2034, which indicated the addition of phosphoethanolamine to the lipid A structure. E. coli BL21 transformed with pET-26b-mcr-4.3 gained colistin resistance with a colistin MIC of 8 mg/L.


Colistin resistance in A. baumannii 597A was correlated with the presence of a novel plasmid-encoded mcr-4.3 gene.


© 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; MCR4; Colistin; Acinetobacter baumannii; Brazil.


Complete nucleotide #sequences of #mcr-4.3-carrying #plasmids in #Acinetobacter baumannii ST345 of #human and #food origin from the #Czech Republic; first case in Europe (Antimicrob Agents Chemother., abstract)

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

Complete nucleotide sequences of mcr-4.3-carrying plasmids in Acinetobacter baumannii ST345 of human and food origin from the Czech Republic; first case in Europe.

Ibrahim Bitar, Matej Medvecky, Tereza Gelbicova, Vladislav Jakubu, Jaroslav Hrabak, Helena Zemlickova, Renata Karpiskova, Monika Dolejska

DOI: 10.1128/AAC.01166-19



Here we describe two plasmids carrying mcr-4.3 in two Acinetobacter baumannii strains isolated from imported food and a clinical sample. The comparative analysis of these plasmids, with two other plasmids reported in NCBI database, highlighted the common origin of the plasmidic structure carrying mcr-4.3. This is the first case of mcr-4.3 gene in A. baumanniistrain isolated from a clinical case in Europe. We hypothesize that food import is initiating the spread in Czech Republic.

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

Keywords: Antibiotics; Drugs Resistance; Colistin; MCR4.3; Acinetobacter baumannii; Human; Food safety; Czech Republic; Plasmids.


Comparative #analysis of an #mcr4 #Salmonella enterica subsp. enterica monophasic variant of #human and #animal origin (J Antimicrob Chemother., abstract)

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

Comparative analysis of an mcr-4 Salmonella enterica subsp. enterica monophasic variant of human and animal origin

Alessandra Carattoli, Edoardo Carretto, Flavia Brovarone, Mario Sarti, Laura Villa

Journal of Antimicrobial Chemotherapy, dky340, https://doi.org/10.1093/jac/dky340

Published: 22 August 2018




In this study we compared the recently described mcr-4-positive Salmonella enterica monophasic variant, isolated in 2016 in two Italian patients affected by gastroenteritis, with the first mcr-4-positive Salmonella isolate identified in 2013 in a pig at slaughter in Italy.


WGS of the two Salmonella isolates of human origin was performed using a MiSeq instrument (Illumina). The phylogenetic analysis was performed by SNP analysis, comparing genomes of the mcr-4-positive isolates of swine and human origin with 82 Salmonella genomes downloaded from the EnteroBase Salmonella database. Complete sequences of plasmids carrying mcr-4.2 were obtained and compared. Transformation experiments were performed to transfer the mcr-4 plasmids into a colistin-susceptible Escherichia coli recipient strain.


Comparative genomics demonstrated that the Salmonella of swine origin did not cluster with the isolates of human origin. The mcr-4.2 gene variant identified in the Salmonella of human origin was located on a ColE-like plasmid. This plasmid showed different replication and mobilization genes with respect to those previously described in the ColE plasmid carrying the mcr-4.1 variant, identified in Salmonella of swine origin.


The divergence in genomes, plasmids and gene variants demonstrated that there was not a unique mcr-4-positive, monophasic Salmonella lineage circulating in animals and causing gastroenteritis in humans in Italy. There was no horizontal transfer of the same plasmid among Salmonella strains of animal and human origin, but the mcr-4 gene and a fragment of the plasmid identified in the animal strain were mobilized by an IS1294 into a different ColE plasmid.


© The Author(s) 2018. 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/about_us/legal/notices)

Keywords: Antibiotics; Drugs Resistance; Colistin; MCR4; Salmonella Enterica; Italy.


Newly identified #colistin #resistance genes, #mcr4 and #mcr5, from upper and lower #alimentary #tract of #pigs and #poultry in #China (PLoS One, abstract)

[Source: PLoS One, full page: (LINK). Abstract, edited.]


Newly identified colistin resistance genes, mcr-4 and mcr-5, from upper and lower alimentary tract of pigs and poultry in China

Li Chen , Jilei Zhang , Jiawei Wang, Patrick Butaye, Patrick Kelly, Min Li, Feng Yang, Jiansen Gong, Afrah Kamal Yassin, Weina Guo, Jing Li, Chunlian Song, Chengming Wang

Published: March 14, 2018 / DOI: https://doi.org/10.1371/journal.pone.0193957



Antimicrobial resistance against colistin has emerged worldwide threatening the efficacy of one of the last-resort antimicrobials used for the treatment of Enterobacteriaceae. To investigate the presence of the recently identified colistin resistance genes (mcr-4, mcr-5) in China, we established PCRs to detect mcr-4 and mcr-5 on 213 anal and 1,339 nasal swabs from apparently healthy pigs (n = 1,454) in nine provinces, and 1,696 cloacal and 1,647 oropharyngeal samples from poultry (n = 1,836) at live-bird markets in 24 provinces of China. The prevalence of the mcr-4 in swine swabs (41.4%; 642/1,552) was significantly higher than in swabs from poultry (11.5%; 384/3,343). The mcr-4 gene was found in geese (49.5%, 54/109), chickens (17.2%, 257/1,498), pigeons (17.2%, 17/99) and ducks (15.4%, 20/130). In a similar trend, the prevalence of the mcr-5 in swine swabs (33.1%; 514/1552) was significantly higher than in swabs from poultry (5.6%; 187/3,343). The mcr-5 was identified in geese (17.4%, 19/109), chickens (9.9%, 148/1,498), ducks (7.7%, 10/130) and pigeons (3%, 3/99). The mcr-4 prevalence in the nasal swabs from pigs (59.2%, 58/98) was significantly higher than that in anal swabs (29.6%, 29/98) (P<0.001). Similarly, the mcr-5 prevalence in the nasal swabs from pigs (61.2%, 60/98) was significantly higher than in anal swabs (44.9%, 44/98) (P = 0.02), and significantly higher in oropharyngeal swabs (7.2%, 109/1,507) than in the cloacal swabs (3.7%, 56/1,507) (P<0.001). This study further confirms the presence of the mcr-4 and mcr-5 in animals and indicates these genes are prevalent and widespread in food producing animals (pig and poultry) in China. Future studies are needed to characterize the bacteria carrying the mcr-4 and mcr-5 and their locations on plasmids and/or the bacterial chromosomes, and determine co-resistances in the mcr-4 and mcr-5 positive strains.


Citation: Chen L, Zhang J, Wang J, Butaye P, Kelly P, Li M, et al. (2018) Newly identified colistin resistance genes, mcr-4 and mcr-5, from upper and lower alimentary tract of pigs and poultry in China. PLoS ONE 13(3): e0193957. https://doi.org/10.1371/journal.pone.0193957

Editor: Roman R. Ganta, Kansas State University, UNITED STATES

Received: January 1, 2018; Accepted: February 21, 2018; Published: March 14, 2018

Copyright: © 2018 Chen et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Data Availability: All relevant data are within the paper and its Supporting Information files. All the nucleotide sequences were submitted to GenBank with accession numbers MG586909 to MG586912 for mcr-4 and MG586913 to MG586915 for mcr-5.

Funding: This work was supported by a grant from the National Key R & D Program of China (2016YFD0500804), a grant from the National Natural Science Foundation of China (NO: 31472225), the Priority Academic Program Development of Jiangsu Higher Education Institutions, and the Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Competing interests: The authors have declared that no competing interests exist.

Keywords: Antibiotics; Drugs Resistance; Colistin; Pigs; Poultry; China; MCR4; MCR5.


#mcr-5 and a novel mcr-5.2 variant in #Escherichia coli isolates from #food and food-producing #animals, #Germany, 2010 to 2017 (J Antimicrob Chemother., abstract)

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

mcr-5 and a novel mcr-5.2 variant in Escherichia coli isolates from food and food-producing animals, Germany, 2010 to 2017

Jens A Hammerl, Maria Borowiak, Silvia Schmoger, Dina Shamoun, Mirjam Grobbel, Burkhard Malorny, Bernd-Alois Tenhagen, Annemarie Käsbohrer

Journal of Antimicrobial Chemotherapy, dky020,https://doi.org/10.1093/jac/dky020

Published: 12 February 2018



Colistin is considered a last-resort antibiotic used to treat severe human infections caused by MDR Gram-negative bacteria. Thus, spread of colistin resistance among humans would be associated with major public health concerns.1,2 In 2015, the first mobile colistin resistance gene, mcr-1, encoding a phosphoethanolamine transferase enzyme, was identified on a transmissible plasmid.3 Soon after, mcr-2 and mcr-3 were detected on other conjugative plasmids in Enterobacteriaceae.4,5 Recently, Carattoli et al.6 and Borowiak et al.7 reported two novel genes, mcr-4 and mcr-5, in Salmonella enterica serovar Typhimurium and d-tartrate-fermenting S. enterica serovar Paratyphi B [Salmonella Paratyphi B (dTa+)], respectively. Both genes were located on non-conjugative ColE plasmids, either transmissible by…

Issue Section: Research letter

© The Author(s) 2018. 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.

Keywords: Antibiotics; Drugs Resistance; Colistin; MCR5; Germany; Food Safety.


Multiplex #PCR for detection of #plasmid-mediated #colistin #resistance determinants, #mcr1, #mcr2, #mcr3, mcr-4 and mcr-5 for surveillance purposes (Euro Surveill., abstract)

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

Multiplex PCR for detection of plasmid-mediated colistin resistance determinants, mcr-1, mcr-2, mcr-3, mcr-4 and mcr-5 for surveillance purposes

Ana Rita Rebelo1, Valeria Bortolaia1, Jette S Kjeldgaard1, Susanne K Pedersen1, Pimlapas Leekitcharoenphon1, Inge M Hansen1, Beatriz Guerra2, Burkhard Malorny3, Maria Borowiak3, Jens Andre Hammerl3, Antonio Battisti4, Alessia Franco4, Patricia Alba4, Agnes Perrin-Guyomard5, Sophie A Granier6, Cristina De Frutos1,2,3,4,5,6,7,8,9, Escobar7, Surbhi Malhotra-Kumar8, Laura Villa9, Alessandra Carattoli9, Rene S Hendriksen1

Affiliations: 1 National Food Institute, Technical University of Denmark, WHO Collaborating Center for Antimicrobial Resistance in Food borne Pathogens and European Union Reference Laboratory for Antimicrobial Resistance, Kongens Lyngby, Denmark; 2 European Food Safety Authority, Parma, Italy; 3 German Federal Institute for Risk Assessment, Berlin, Germany; 4 National Reference Laboratory for antimicrobial resistance, Istituto Zooprofilattico Sperimentale del Lazio e della Toscana, Rome, Italy; 5 Anses, Fougères Laboratory, Fougères, France; 6 Université Paris-Est, Anses, Laboratory for Food Safety, Maisons-Alfort, France; 7 Laboratorio Central de Veterinaria, (LCV Algete), Madrid, Spain; 8 Laboratory of Medical Microbiology, Vaccine & Infectious Disease Institute, University of Antwerp, Wilrijk, Belgium; 9 Department of Infectious Diseases, Istituto Superiore di Sanità, Rome, Italy

Correspondence: Rene S. Hendriksenrshe food.dtu.dk

Citation style for this article: Rebelo Ana Rita, Bortolaia Valeria, Kjeldgaard Jette S, Pedersen Susanne K, Leekitcharoenphon Pimlapas, Hansen Inge M, Guerra Beatriz, Malorny Burkhard, Borowiak Maria, Hammerl Jens Andre, Battisti Antonio, Franco Alessia, Alba Patricia, Perrin-Guyomard Agnes, Granier Sophie A, De Frutos Cristina , Escobar, Malhotra-Kumar Surbhi, Villa Laura, Carattoli Alessandra, Hendriksen Rene S. Multiplex PCR for detection of plasmid-mediated colistin resistance determinants, mcr-1, mcr-2, mcr-3, mcr-4 and mcr-5 for surveillance purposes. Euro Surveill. 2018;23(6):pii=17-00672. https://doi.org/10.2807/1560-7917.ES.2018.23.6.17-00672



Background and aim

Plasmid-mediated colistin resistance mechanisms have been identified worldwide in the past years. A multiplex polymerase chain reaction (PCR) protocol for detection of all currently known transferable colistin resistance genes (mcr-1 to mcr-5, and variants) in Enterobacteriaceae was developed for surveillance or research purposes.


We designed four new primer pairs to amplify mcr-1, mcr-2, mcr-3 and mcr-4 gene products and used the originally described primers for mcr-5 to obtain a stepwise separation of ca 200 bp between amplicons. The primer pairs and amplification conditions allow for single or multiple detection of all currently described mcr genes and their variants present in Enterobacteriaceae. The protocol was validated testing 49 European Escherichia coli and Salmonella isolates of animal origin.


Multiplex PCR results in bovine and porcine isolates from Spain, Germany, France and Italy showed full concordance with whole genome sequence data. The method was able to detect mcr-1, mcr-3 and mcr-4 as singletons or in different combinations as they were present in the test isolates. One new mcr-4 variant, mcr-4.3, was also identified.


This method allows rapid identification of mcr-positive bacteria and overcomes the challenges of phenotypic detection of colistin resistance. The multiplex PCR should be particularly interesting in settings or laboratories with limited resources for performing genetic analysis as it provides information on the mechanism of colistin resistance without requiring genome sequencing.

© This work is licensed under a Creative Commons Attribution 4.0 International License.

Keywords: Antibiotics; Drugs Resistance; Colistin; MCR1; MCR2; MCR3; MCR4; Diagnostic Tests.


#Plasmid-encoded #colistin #resistance: #mcr-one, two, three and counting (@eurosurveillanc, summary)

[Source: Eurosurveillance, full page: (LINK). Summary, edited.]

Eurosurveillance, Volume 22, Issue 31, 03 August 2017 / Editorial

Plasmid-encoded colistin resistance: mcr-one, two, three and counting

J Kluytmans 1

Author affiliations: 1. Amphia Hospital Breda and University Medical Centre Utrecht

Correspondence: Jan Kluytmans (jankluytmans@gmail.com)

Citation style for this article: Kluytmans J. Plasmid-encoded colistin resistance: mcr-one, two, three and counting. Euro Surveill. 2017;22(31):pii=30588. DOI: http://dx.doi.org/10.2807/1560-7917.ES.2017.22.31.30588

Received:20 July 2017; Accepted:20 July 2017



In November 2015, the first description of plasmid-mediated colistin resistance (mcr-1 gene) was reported from China in food animals, food and humans [1]. Many reports from all over the world have followed since. The reported rates vary considerably, ranging from sporadic findings up to 67% in Escherichia coli isolates from Tunisian chicken [2]. However, the rates have been consistently higher in livestock than in humans. This points to a reservoir in animals with spill over to humans. Until recently, colistin use in humans has been limited but it has been used extensively in veterinary medicine for decades, both as curative treatment and for prevention of disease [3]. The amount of use in livestock varies enormously. In Europe, for example, in 2013, the annual colistin sales in some countries exceeded 20 mg per population corrected unit (PCU) while in other countries the sales were below 1 mg/PCU. Following the detection of mcr-1, the European Medicines Agency updated their advice on the use of colistin in humans and animals [3] with the aim of reducing the use in animals by 65% in the coming years. Quantitative targets of 5 mg/PCU and 1 mg/PCU have been set for a reduction in high and medium consuming countries, respectively.


Keywords: Antibiotics; Drugs Resistance; Colistin; MCR1; MCR3.