#Plasmid-Mediated #mcr-1 #Colistin #Resistance in #Escherichia coli from a Black Kite in #Russia (Antimicrob Agents Chemother., abstract)

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

Plasmid-Mediated mcr-1 Colistin Resistance in Escherichia coli from a Black Kite in Russia

Hassan Tarabai, Adam Valcek, Ivana Jamborova, Sergey V. Vazhov, Igor V. Karyakin, Rainer Raab, Ivan Literak, Monika Dolejska

DOI: 10.1128/AAC.01266-19



The gene mcr-1 conferring resistance to last-line antibiotic colistin has been reported globally. Here we describe the first detection of plasmid-mediated colistin resistance in Russian wildlife, an isolate of Escherichia coli sequence type 2280 from a black kite (Milvus migrans), scavenging raptor. Whole genome sequencing and plasmid transferability experiments revealed that mcr-1.1 was located on a conjugative IncI2 plasmid pDR164 (59891 bp). Migratory Black Kites may contribute to the global spread of mobile colistin resistance.

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

Keywords: Antibiotics; Drugs Resistance; Colistin; MCR1; E. Coli; Wild Birds; Russia.



#Resistance to critically important #antimicrobials in #Australian silver #gulls (Chroicocephalus novaehollandiae) and evidence of #anthropogenic origins (J Antimicrob Chemother., abstract)

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

Resistance to critically important antimicrobials in Australian silver gulls (Chroicocephalus novaehollandiae) and evidence of anthropogenic origins

Shewli Mukerji, Marc Stegger, Alec Vincent Truswell, Tanya Laird, David Jordan, Rebecca Jane Abraham, Ali Harb, Mary Barton, Mark O’Dea, Sam Abraham

Journal of Antimicrobial Chemotherapy, dkz242, https://doi.org/10.1093/jac/dkz242

Published: 09 July 2019




Antimicrobial resistance (AMR) to critically important antimicrobials (CIAs) amongst Gram-negative bacteria can feasibly be transferred amongst wildlife, humans and domestic animals. This study investigated the ecology, epidemiology and origins of CIA-resistant Escherichia coli carried by Australian silver gulls (Chroicocephalus novaehollandiae), a gregarious avian wildlife species that is a common inhabitant of coastal areas with high levels of human contact.


Sampling locations were widely dispersed around the perimeter of the Australian continent, with sites separated by up to 3500 km. WGS was used to study the diversity and molecular characteristics of resistant isolates to ascertain their epidemiological origin.


Investigation of 562 faecal samples revealed widespread occurrence of extended-spectrum cephalosporin-resistant (21.7%) and fluoroquinolone-resistant (23.8%) E. coli. Genome sequencing revealed that CIA-resistant E. coliisolates (n = 284) from gulls predominantly belonged to human-associated extra-intestinal pathogenic E. coli (ExPEC) clones, including ST131 (17%), ST10 (8%), ST1193 (6%), ST69 (5%) and ST38 (4%). Genomic analysis revealed that gulls carry pandemic ExPEC-ST131 clades (O25:H4 H30-R and H30-Rx) and globally emerging fluoroquinolone-resistant ST1193 identified among humans worldwide. Comparative analysis revealed that ST131 and ST1193 isolates from gulls overlapped extensively with human clinical isolates from Australia and overseas. The present study also detected single isolates of carbapenem-resistant E. coli (ST410-blaOXA-48) and colistin-resistant E. coli (ST345-mcr-1).


The carriage of diverse CIA-resistant E. coli clones that strongly resemble pathogenic clones from humans suggests that gulls can act as ecological sponges indiscriminately accumulating and disseminating CIA-resistant bacteria over vast distances.

Topic: colistin – epidemiology – animals, domestic – australia – aves – clone cells – disease transmission – drug resistance, microbial – ecology – feces – fluoroquinolones – genome – gram-negative bacteria – intestines – prescriptions, drug – surgical sponges – bacteria – silver – antimicrobials – escherichia coli – pandemics – genome sequencing – carbapenem resistance – extraintestinal pathogenic escherichia coli – whole genome sequencing


© 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; Colistin; Fluoroquinolones; MCR1; E.Coli; Wild Birds; Australia.


#Pandemic #fluoroquinolone #resistant #Escherichia coli clone #ST1193 emerged via simultaneous homologous #recombinations in 11 gene loci (Proc Natl Acad Sci USA, abstract)

[Source: Proceedings of the National Academy of Sciences of the United States of America, full page: (LINK). Abstract, edited.]

Pandemic fluoroquinolone resistant Escherichia coli clone ST1193 emerged via simultaneous homologous recombinations in 11 gene loci

Veronika Tchesnokova, Matthew Radey, Sujay Chattopadhyay, Lydia Larson, Jamie Lee Weaver, Dagmara Kisiela, and Evgeni V. Sokurenko

PNAS first published July 1, 2019 / DOI: https://doi.org/10.1073/pnas.1903002116

Edited by W. Ford Doolittle, Dalhousie University, Halifax, NS, Canada, and approved June 5, 2019 (received for review February 19, 2019)



Global growth in antibiotic resistance is a major social and health problem. The most common mechanism of high resistance to fluoroquinolones is the sequential acquisition of 3 mutations in 2 DNA topoisomerases, GyrA and ParC. We show that Escherichia coliST1193 acquired the mutant variants of gyrA and parC not by a conventional stepwise evolution but rather all at once. This was likely a result of a single transfer of about 1 Mb of chromosomal DNA from a phylogenetically distant donor E. coli strain, followed by 11 homologous recombination events involving the transferred DNA. Thus we describe a highly effective mechanism of acquisition of antimicrobial resistance by pathogenic bacteria, which led to the emergence of pandemic E. coli clone ST1193.



Global growth in antibiotic resistance is a major social problem. A high level of resistance to fluoroquinolones requires the concurrent presence of at least 3 mutations in the target proteins—2 in DNA gyrase (GyrA) and 1 in topoisomerase IV (ParC), which occur in a stepwise manner. In the Escherichia coli chromosome, the gyrA and parC loci are positioned about 1 Mb away from each other. Here we show that the 3 fluoroquinolone resistance mutations are tightly associated genetically in naturally occurring strains. In the latest pandemic uropathogenic and multidrug-resistant E. coli clonal group ST1193, the mutant variants of gyrA and parC were acquired not by a typical gradual, stepwise evolution but all at once. This happened as part of 11 simultaneous homologous recombination events involving 2 phylogenetically distant strains of E. coli, from an uropathogenic clonal complex ST14 and fluoroquinolone-resistant ST10. The gene exchanges swapped regions between 0.5 and 139 Kb in length (183 Kb total) spread along 976 Kb of chromosomal DNA around and between gyrA and parC loci. As a result, all 3 fluoroquinolone resistance mutations in GyrA and ParC have simultaneously appeared in ST1193. Based on molecular clock estimates, this potentially happened as recently as <12 y ago. Thus, naturally occurring homologous recombination events between 2 strains can involve numerous chromosomal gene locations simultaneously, resulting in the transfer of distant but tightly associated genetic mutations and emergence of a both highly pathogenic and antibiotic-resistant strain with a rapid global spread capability.

Escherichia coli ST1193 – urinary tract infections – resistance to fluoroquinolones – homologous recombination – QRDR mutations



1 To whom correspondence may be addressed. Email: evs@uw.edu.

Author contributions: V.T. and E.V.S. designed research; V.T., M.R., S.C., L.L., J.L.W., and D.K. performed research; V.T., M.R., S.C., D.K., and E.V.S. analyzed data; and V.T., M.R., S.C., and E.V.S. wrote the paper.

The authors declare no conflict of interest.

This article is a PNAS Direct Submission.

This article contains supporting information online at www.pnas.org/lookup/suppl/doi:10.1073/pnas.1903002116/-/DCSupplemental.

Published under the PNAS license.

Keywords: Antibiotics; Drugs Resistance; Fluoroquinolones; E. Coli; Recombination.


Detection of #plasmid-mediated #tigecycline-resistant gene tet(X4) in #Escherichia coli from #pork, #Sichuan and #Shandong Provinces, #China, February 2019 (Euro Surveill., abstract)

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

Detection of plasmid-mediated tigecycline-resistant gene tet(X4) in Escherichia coli from pork, Sichuan and Shandong Provinces, China, February 2019

Li Bai1,2,3, Pengcheng Du3,4, Yinju Du5, Honghu Sun1,2,6, Pei Zhang1,2, Yuping Wan6, Qi Lin6, Séamus Fanning1,2,7, Shenghui Cui8, Yongning Wu1,2

Affiliations: 1 Key Laboratory of Food Safety Risk Assessment, National Health Commission of the People’s Republic of China, Beijing, People’s Republic of China; 2 Food Safety Research Unit of Chinese Academy of Medical Sciences, China National Center for Food Safety Risk Assessment, Beijing, People’s Republic of China; 3 These authors contributed equally to this work; 4 Institute of Infectious Diseases, Beijing Ditan Hospital, Capital Medical University, and Beijing Key Laboratory of Emerging Infectious Diseases, Beijing, People’s Republic of China; 5 Center for disease control and prevention of Liaocheng city, Liaocheng, People’s Republic of China; 6 Chengdu institute for Food and Drug Control, Chengdu, People’s Republic of China; 7 UCD-Centre for Food Safety, School of Public Health, Physiotherapy and Sports Science, University College Dublin, Belfield, Dublin, Ireland; 8 Department of Food Science, National Institutes for Food and Drug Control, Beijing, People’s Republic of China

Correspondence:  Yongning Wu

Citation style for this article: Bai Li, Du Pengcheng, Du Yinju, Sun Honghu, Zhang Pei, Wan Yuping, Lin Qi, Fanning Séamus, Cui Shenghui, Wu Yongning. Detection of plasmid-mediated tigecycline-resistant gene tet(X4) in Escherichia coli from pork, Sichuan and Shandong Provinces, China, February 2019. Euro Surveill.2019;24(25):pii=1900340. https://doi.org/10.2807/1560-7917.ES.2019.24.25.1900340

Received: 29 May 2019;   Accepted: 20 Jun 2019



The plasmid-mediated high-level tigecycline resistance gene, tet(X4), was detected in seven Escherichia coli isolates from pork in two Chinese provinces. Two isolates belonged to the epidemic spreading sequence type ST101. Tet(X4) was adjacent to ISVsa3 and concurrent with floR in all seven isolates. In addition to IncFIB, the replicon IncFII was found to be linked to tet(X4). This report follows a recent detection of tet(X3)/(X4) in E. coli from animals and humans in China.

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

Keywords: Antibiotics; Drugs Resistance; Tigecycline; Plasmids; Pigs; E. Coli; Food Safety; China; Sichuan; Shandong.


#mcr-9, an inducible #gene encoding an acquired phosphoethanolamine transferase in #Escherichia coli, and its origin (Antimicrob Agents Chemother., abstract)

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

mcr-9, an inducible gene encoding an acquired phosphoethanolamine transferase in Escherichia coli, and its origin

Nicolas Kieffer, Guilhem Royer, Jean-Winoc Decousser, Anne-Sophie Bourrel, Mattia Palmieri, Jose-Manuel Ortiz De La Rosa, Hervé Jacquier, Erick Denamur, Patrice Nordmann,Laurent Poirel

DOI: 10.1128/AAC.00965-19



The plasmid-located mcr-9 gene encoding a putative phosphoethanolamine transferase was identified in a colistin-resistant human fecal Escherichia coli belonging to a very rare phylogroup D-ST69-O15:H6 clone. This MCR-9 protein shares 33-65% identity with the other plasmid-encoded MCR-type enzymes identified (MCR-1- to -8) that have been found as sources of acquired resistance to polymyxins in Enterobacteriaceae. Analysis of the lipopolysaccharide of the MCR-9-producing isolate revealed a similar function as MCR-1 by adding a phosphoethanolamine group to the lipid A and subsequently modifying the structure of the lipopolysaccharide. However, a minor impact on susceptibility to polymyxins was noticed once cloned and produced in an E. coli K-12 derived strain. Nevertheless, we showed here that sub-inhibitory concentrations of colistin induced the expression of the mcr-9 gene, leading to increased MIC levels. This inducible expression was mediated by a two-component regulatory system encoded by the qseC and qseB genes located downstream of mcr-9. Genetic analysis showed that the mcr-9 gene was carried by an IncHI2 plasmid. In silico analysis revealed that the plasmid-encoded MCR-9 shared significant amino acid identity (ca. 80%) with the chromosomally-encoded MCR-like proteins from Buttiauxella spp. In particular, Buttiauxella gaviniae was found to harbor a gene encoding MCR-BG, sharing 84% identity with MCR-9. That gene was neither expressed nor inducible in its original host, which was fully susceptible to polymyxins. This work showed that mcr genes may circulate quite silently and remaining undetected unless induced by colistin.

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

Keywords: Antibiotics; Drugs Resistance; MCR9; Colistin; E. Coli.


Repeated detection of #carbapenemase-producing #Escherichia coli in #gulls inhabiting #Alaska, #USA (Antimicrob Agents Chemother., abstract)

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

Repeated detection of carbapenemase-producing Escherichia coli in gulls inhabiting Alaska, USA

Christina A. Ahlstrom, Andrew M. Ramey, Hanna Woksepp, Jonas Bonnedahl

DOI: 10.1128/AAC.00758-19



We report the first detection of carbapenemase-producing Escherichia coli in Alaska and in wildlife in the United States. Wild bird (gull) feces sampled at three locations in Southcentral Alaska yielded isolates that harbored plasmid-encoded blaKPC-2 or chromosomally-encoded blaOXA-48, and genes associated with antimicrobial resistance to up to eight antibiotic classes.

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

Keywords: Antibiotics; Drugs Resistance; Carbapenem; E. Coli; Wild birds; Alaska; USA.


#Molecular characterization of #carbapenem-resistant #Escherichia coli and #Acinetobacter baumannii in the #Lao People’s Democratic Republic (J Antimicrob Chemother., summary)

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

Molecular characterization of carbapenem-resistant Escherichia coli and Acinetobacter baumannii in the Lao People’s Democratic Republic

Tomas-Paul Cusack, Vilayouth Phimolsarnnousith, Khuanta Duangmala, Phonelavanh Phoumin, Jane Turton, Katie L Hopkins, Neil Woodford, Nandini Shetty, Nicole Stoesser, Hang T T Phan, David A B Dance

Journal of Antimicrobial Chemotherapy, dkz234, https://doi.org/10.1093/jac/dkz234

Published: 05 June 2019



Global dissemination of carbapenemases among Gram-negative bacteria is a growing public health concern. Therapeutic options for these organisms are often limited, with alternative agents such as tigecycline and colistin having potentially less favourable efficacy and toxicity profiles.1,2 Furthermore, these agents are expensive and not readily available in resource-constrained settings. In the Lao People’s Democratic Republic (Laos), carbapenems are not yet on the national list of essential drugs, although in Vientiane the high prevalence of ESBL-producing Enterobacterales3,4 has driven more widespread use of carbapenems imported by individual pharmacies from neighbouring countries. However, while carbapenem-resistant Enterobacterales (CRE) and carbapenem-resistant Acinetobacter baumannii(CRAB) have been described in neighbouring Thailand and Vietnam,5 little is known about carbapenem resistance in Laos, where few laboratories perform antimicrobial susceptibility testing (AST) and surveillance networks are not well established.




The Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit (LOMWRU) is core funded by Wellcome (grant number 106698/Z/14/Z). The funding body had no role in: the design of the study; collection, analysis and interpretation of data; and writing of the manuscript. Study-related work at the other sites was supported by internal funding.

Transparency declarations

None to declare.

Keywords: Antibiotics; Drugs Resistance; Carbapenem; Acinetobacter baumannii; E. Coli; Laos.