Conjugative IncX 1 #plasmid harboring #colistin #resistance gene #mcr-5.1 in #E coli isolated from #chicken rice retailed in #Singapore (Antimicrob Agents Chemother., abstract)

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

Conjugative IncX 1 plasmid harboring colistin resistance gene mcr-5.1 in E. coli isolated from chicken rice retailed in Singapore

Siyao Guo, Moon Y.F. Tay, Aung Kyaw Thu, Kelyn Lee Ghee Seow, Yang Zhong, Lee Ching Ng, Joergen Schlundt

DOI: 10.1128/AAC.01043-19



Colistin is regarded as one of the last resort antimicrobials to Gram-negative bacterial infection (1).…


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

Keywords: Antibiotics; Drugs Resistance; Colistin; MCR5; Plasmids; Food Safety; Singapore.



#Control and #Elimination of #XDR #Acinetobacter baumanii in an #ICU (Emerg Infect Dis., abstract)

[Source: US Centers for Disease Control and Prevention (CDC), Emerging Infectious Diseases Journal, full page: (LINK). Abstract, edited.]

Volume 25, Number 10—October 2019 / Dispatch

Control and Elimination of Extensively Drug-Resistant Acinetobacter baumanii in an Intensive Care Unit

Amanda Chamieh1, Tania Dagher Nawfal1, Tala Ballouz1, Claude Afif, George Juvelekian, Sani Hlais, Jean-Marc Rolain, and Eid Azar

Author affiliations: University of Balamand, Beirut, Lebanon (A. Chamieh, T. Ballouz, C. Afif, G. Juvelekian, E. Azar); Aix-Marseille University, Marseille, France (T.D. Nawfal, J.-M. Rolain); Saint Joseph University and American University of Beirut, Beirut (S. Hlais)



We decreased antimicrobial drug consumption in an intensive care unit in Lebanon by changing to colistin monotherapy for extensively drug-resistant Acinetobacter baumanii infections. We saw a 78% decrease of A. baumanii in sputum and near-elimination of blaoxa-23-carrying sequence type 2 clone over the 1-year study. Non–A. baumanii multidrug-resistant infections remained stable.

Keywords: Antibiotics; Drugs Resistance; Colistin; Acinetobacter baumannii; Lebanon; ICU.


Detection of a novel #mcr-5.4 gene variant in #hospital tap #water by shotgun #metagenomic sequencing (J Antimicrob Chemother., summary)

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

Detection of a novel mcr-5.4 gene variant in hospital tap water by shotgun metagenomic sequencing

Giuseppe Fleres, Natacha Couto, Leonard Schuele, Monika A Chlebowicz,Catarina I Mendes, Luc W M van der Sluis, John W A Rossen, Alex W Friedrich,Silvia García-Cobos

Journal of Antimicrobial Chemotherapy, dkz363,

Published: 23 August 2019

Issue Section: Research letter



Colistin is considered a last-resort antibiotic for treating serious infections caused by MDR Gram-negative bacteria. The efficacy of this antibiotic is challenged by the emergence and global spread of mobile colistin resistance (mcr) determinants, which threaten human, animal and environmental health. The first mobile colistin resistance gene (mcr-1) was reported in 2015 and since then up to eight different variants have been described.1 In 2017, Borowiak et al.2 described a new transposon-associated phosphoethanolamine transferase mediating colistin resistance, named mcr-5, in d-tartrate-fermenting Salmonella enterica subsp. enterica serovar Paratyphi B isolated from poultry. The mcr-5.3 variant has been recently reported in Stenotrophomonas spp. from sewage water.3 Here we report for the first time (to the best of our knowledge) the detection of an mcr-5 gene in a hospital water environment using short-read metagenomic sequencing (SRMseq) and subsequent characterization using long-read metagenomic sequencing (LRMseq) to reveal its genetic environment.




We would like to thank Erwin C. Raangs for technical assistance.


This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement 713660 (MSCA-COFUND-2015-DP ‘Pronkjewail’), which includes in-kind contributions by commercial partners. None of the commercial partners had any influence on interpretation of reviewed data and conclusions drawn, or on drafting of the manuscript. This work was partly supported by the INTERREG VA (202085)-funded project EurHealth-1Health, part of a Dutch–German cross-border network supported by the European Commission, the Dutch Ministry of Health, Welfare and Sport (VWS), the Ministry of Economy, Innovation, Digitalization and Energy of the German Federal State of North Rhine-Westphalia and the German Federal State of Lower Saxony.

Transparency declarations

None to declare.

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


Activity of #imipenem / #relebactam against #carbapenemase-producing #Enterobacteriaceae with high #colistin resistance (J Antimicrob Chemother., abstract)

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

Activity of imipenem/relebactam against carbapenemase-producing Enterobacteriaceae with high colistin resistance

Jessica Carpenter, Nick Neidig, Alex Campbell, Tanner Thornsberry, Taylor Truex,Tiffany Fortney, Yunliang Zhang, Karen Bush

Journal of Antimicrobial Chemotherapy, dkz354,

Published: 20 August 2019




Imipenem/relebactam, an investigational β-lactam/β-lactamase inhibitor combination for treatment of Gram-negative infections, and comparators including ceftazidime/avibactam, piperacillin/tazobactam and colistin were tested for activity against representative carbapenemase-producing Enterobacteriaceae (CPE) isolates.


MICs of the antimicrobial agents were determined using standard broth microdilution methodology for CPE isolates collected from Indiana patients, primarily during the time frame of 2013–17 (n = 199 of a total of 200 isolates). Inhibitors were tested at 4 mg/L in all combinations.


Of the CPE in the study, 199 produced plasmid-encoded KPC class A carbapenemases; 1 Serratia marcescens isolate produced the SME-1 chromosomal class A carbapenemase. MIC50/MIC90 values of imipenem/relebactam were ≤0.25/0.5 mg/L, whereas MIC50/MIC90 values of ceftazidime/avibactam were 1/2 mg/L. Resistance to colistin was observed in 54% (n = 97) of 180 non-Serratia isolates tested (MIC50 of 4 mg/L). Colistin resistance mechanisms included production of a plasmid-encoded mcr-1-like gene (n = 2) or an inactivated mgrB gene.


Imipenem/relebactam was the most potent agent tested against CPE in this study and may be a useful addition to the antimicrobial armamentarium to treat infections caused by these pathogens.


© 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:

This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model (

Keywords: Antibiotics; Drugs Resistance; Carbapenem; Colistin; MCR1; Enterobacteriaceae; Imipenem; Relebactam.


In Vitro Activity of #Minocycline against #US Isolates of #Acinetobacter baumannii – Acinetobacter calcoaceticus species complex, …: Results from the SENTRY Antimicrobial Surveillance Program (2014-2018) (Antimicrob Agents Chemother., abstract)

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

In Vitro Activity of Minocycline against U.S. Isolates of Acinetobacter baumannii-Acinetobacter calcoaceticus species complex, Stenotrophomonas maltophilia, and Burkholderia cepacia complex: Results from the SENTRY Antimicrobial Surveillance Program (2014-2018)

Robert K. Flamm, Dee Shortridge, Mariana Castanheira, Helio S. Sader, Michael A. Pfaller

DOI: 10.1128/AAC.01154-19



We evaluated the activity of minocycline and comparator agents against a large number of Stenotrophomonas maltophilia (n = 1,289), Acinetobacter baumannii-Acinetobacter calcoaceticus species complex (n = 1,081), and Burkholderia cepacia complex (n = 101) collected during 2014 through 2018 from 87 U.S. medical centers spanning all nine census divisions. The isolates were collected primarily from hospitalized patients with pneumonia (1,632 isolates; 66.0% overall), skin and skin structure infections (354 isolates; 14.3% overall), bloodstream infections (266 isolates; 10.8% overall), urinary tract infections (126 isolates; 5.1% overall), intra-abdominal infections (61 isolates; 2.5% overall), and other infections (32 isolates; 1.3% overall). Against A. baumannii-A. calcoaceticus species complex, colistin was the most active agent exhibiting MIC50/90 values at ≤0.5/2 μg/ml and 92.4% susceptible. Minocycline ranked second in activity with MIC50/90 values at 0.25/8 μg/ml and susceptibility at 85.7%. Activity for these two agents was reduced against extensively drug-resistant and multidrug-resistant isolates of Acinetobacter baumannii-Acinetobacter calcoaceticus species complex. Only two agents showed high levels of activity (susceptibility >90%) against S. maltophilia: minocycline (MIC50/90, 0.5/2 μg/ml; 99.5% susceptible) and trimethoprim-sulfamethoxazole (MIC50/90, ≤0.5/1 μg/ml; 94.6% susceptible). Minocycline was active against 92.8% (MIC90, 4 μg/ml) of trimethoprim-sulfamethoxazole-resistant S. maltophilia isolates. Various agents exhibited susceptibility rates of nearly 90% against B. cepacia complex: trimethoprim-sulfamethoxazole (MIC50/90, ≤0.5/2 μg/ml; 93.1% susceptible), ceftazidime (MIC50/90, 2/8 μg/ml; 91.0%), meropenem (MIC50/90, 2/8 μg/ml; 89.1%) and minocycline (MIC50/90, 2/8 μg/ml; 88.1% susceptible). These results indicate that minocycline is among the most active agents for these three problematic potential pathogen groups when tested against U.S. isolates.

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

Keywords: Antibiotics; Drugs Resistance; Minocycline; Colistin; Acinetobacter baumannii; Burkholderia cepacia; USA.


#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




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


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.


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.


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.


Emergence of a hybrid #plasmid derived from IncN1-F33:A−:B− and #mcr-1-bearing plasmids mediated by IS26 (J Antimicrob Chemother., abstract)

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

Emergence of a hybrid plasmid derived from IncN1-F33:A−:B− and mcr-1-bearing plasmids mediated by IS26

Dandan He, Yingying Zhu, Ruichao Li, Yushan Pan, Jianhua Liu, Li Yuan,Gongzheng Hu

Journal of Antimicrobial Chemotherapy, dkz327,

Published: 30 July 2019




To characterize the complete sequences of four plasmids in MCR-1-producing clinical Escherichia coli strain D72, and to depict the formation mechanism and characteristics of the cointegrate plasmid derived from the pD72-mcr1 and pD72-F33 plasmids.


The genetic profiles of plasmids in strain D72 and its transconjugant were determined by conjugation, S1-PFGE, Southern hybridization, WGS analysis and PCR. Plasmid sequences were analysed with bioinformatic tools. The traits of the fusion plasmid were characterized by cointegration, stability and conjugation assays.


Strain D72, belonging to ST1114, contained four plasmids, including mcr-1-carrying pD72-mcr1, blaCTX-M-55-carrying pD72-F33, blaTEM-238-bearing pD72-IncP and pD72-IncX1 carrying aph(3′)-Ia, qnrS2 and floR. A single plasmid, pD72C, in the transconjugant was found to be larger than any plasmid in the original strain D72. Sequence analysis showed that pD72C was the fusion product of pD72-mcr1 and pD72-F33, and the recombinant event involved an intermolecular replicative mechanism. Plasmid fusion occurred at a frequency of 1.75 × 10−4 cointegrates per transconjugant. The fusion plasmid presented a high stability and conjugation frequency of 8.00 × 10−3.


To our knowledge, this is the first report of the IS26-mediated fusion of an IncN1-F33:A−:B− plasmid and an mcr-1-carrying phage-like plasmid, providing evidence for the important role of IS26 in the recombination of plasmids. The biological advantages of the fusion plasmid indicated that the fusion event presumably plays a potential role in the dissemination of mcr-1.

Keywords: Antibiotics; Drugs Resistance; Colistin; E. Coli; MCR1; Plasmids.