Colistin Resistance: The Need for a One Health Approach

A special issue of Antibiotics (ISSN 2079-6382). This special issue belongs to the section "Antibiotics Use and Antimicrobial Stewardship".

Deadline for manuscript submissions: closed (31 December 2021) | Viewed by 33902

Special Issue Editors


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Guest Editor
Department of Veterinary Sciences, University of Pisa, Pisa, Italy
Interests: Staphylococcus spp.; E. coli; antimicrobial resistance; probiotics
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Special Issue Information

Dear Colleagues,

Antimicrobial resistance represents one of the main concerns worldwide. Some studies contemplate the possibility of a return to the so-called “pre-antibiotic era” in a few years. In the past few years, there have been different emergencies like, for example, those related to the methicillin resistance in Staphylococcus aureus or the production of extended spectrum beta-lactamase by Enterobacteriaceae. Recently, the discovery of a plasmid gene (mcr-1) responsible for transferable colistin resistance in E. coli, opened a new potential crisis. Colistin is an antibiotic belonging to the class of Polymyxins and it is largely used in veterinary medicine and considered a “last choice” antimicrobial in human therapy, to treat infections caused by multidrug-resistant bacteria. Since the first detection of mcr-1 in 2015, many other mcr variants were discovered in isolates from humans, animals, and foods, generally associated with high colistin MIC values. To better understand this emergent problem, an integrated approach involving human and veterinary medicine, as well as environmental aspects, is essential.

This Special Issue welcomes every kind of contributions focusing on colistin resistance. Basic studies exploring new variants or modes of action of mcr genes are considered. Investigations exploring this topic with phenotypic and molecular methods are encouraged. “Epidemiological” studies describing the circulation of bacteria showing colistin resistance among humans, animals, food, and environmental samples from different areas of the world are of great interest.

Dr. Fabrizio Bertelloni
Dr. Barbara Turchi
Guest Editors

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Keywords

  • Colistin resistance
  • mcr genes
  • humans
  • veterinary
  • food
  • environment
  • epidemiology

Published Papers (12 papers)

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Editorial

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4 pages, 209 KiB  
Editorial
Editorial for the Special Issue: Colistin Resistance—The Need for a One Health Approach
by Fabrizio Bertelloni and Barbara Turchi
Antibiotics 2022, 11(9), 1167; https://doi.org/10.3390/antibiotics11091167 - 30 Aug 2022
Viewed by 1056
Abstract
Colistin is an “old” antimicrobial belonging to the class of polymyxins, initially discovered in 1947 [...] Full article
(This article belongs to the Special Issue Colistin Resistance: The Need for a One Health Approach)

Research

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9 pages, 1093 KiB  
Article
Identification of mcr-1 Genes and Characterization of Resistance Mechanisms to Colistin in Escherichia coli Isolates from Colombian Hospitals
by Elsa De La Cadena, Mateo Mahecha, Ana María Velandia, Juan Carlos García-Betancur, Laura J. Rojas, Jessica Porras, Christian Pallares and María Virginia Villegas
Antibiotics 2023, 12(3), 488; https://doi.org/10.3390/antibiotics12030488 - 01 Mar 2023
Cited by 1 | Viewed by 1671
Abstract
We report the presence of the mcr-1 gene among 880 Escherichia coli clinical isolates collected in 13 hospitals from 12 Colombian cities between 2016 and 2019. Seven (0.8%) isolates were colistin resistant (MIC ≥ 4 µg/mL). These colistin-resistant isolates were screened for the [...] Read more.
We report the presence of the mcr-1 gene among 880 Escherichia coli clinical isolates collected in 13 hospitals from 12 Colombian cities between 2016 and 2019. Seven (0.8%) isolates were colistin resistant (MIC ≥ 4 µg/mL). These colistin-resistant isolates were screened for the presence of the mcr-1 gene; five carried the gene. These five isolates were subjected to whole genome sequencing (WGS) to identify additional resistomes and their ST. In addition, antimicrobial susceptibility testing revealed that all E. coli isolates carrying mcr-1 were susceptible to third generation-cephalosporin and carbapenems, except one, which carried an extended-spectrum β-lactamase (CTX-M-55), along with the fosfomycin resistance encoding gene, fosA. WGS indicated that these isolates belonged to four distinct sequence types (ST58, ST46, ST393, and a newly described ST14315) and to phylogroups B1, A, and D. In this geographic region, the spread of mcr-1 in E. coli is low and has not been inserted into high-risk clones such as ST131, which has been present in the country longer. Full article
(This article belongs to the Special Issue Colistin Resistance: The Need for a One Health Approach)
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12 pages, 595 KiB  
Article
Whole-Genome Sequencing of a Colistin-Resistant Acinetobacter baumannii Strain Isolated at a Tertiary Health Facility in Pretoria, South Africa
by Noel-David Nogbou, Mbudzeni Ramashia, Granny Marumo Nkawane, Mushal Allam, Chikwelu Lawrence Obi and Andrew Munyalo Musyoki
Antibiotics 2022, 11(5), 594; https://doi.org/10.3390/antibiotics11050594 - 28 Apr 2022
Cited by 7 | Viewed by 2514
Abstract
Background: Acinetobacter baumannii’s (A. baumannii) growing resistance to all available antibiotics is of concern. The study describes a colistin-resistant A. baumannii isolated at a clinical facility from a tracheal aspirate sample. Furthermore, it determines the isolates’ niche establishment ability within [...] Read more.
Background: Acinetobacter baumannii’s (A. baumannii) growing resistance to all available antibiotics is of concern. The study describes a colistin-resistant A. baumannii isolated at a clinical facility from a tracheal aspirate sample. Furthermore, it determines the isolates’ niche establishment ability within the tertiary health facility. Methods: An antimicrobial susceptibility test, conventional PCR, quantitative real-time PCR, phenotypic evaluation of the efflux pump, and whole-genome sequencing and analysis were performed on the isolate. Results: The antimicrobial susceptibility pattern revealed a resistance to piperacillin/tazobactam, ceftazidime, cefepime, cefotaxime/ceftriaxone, imipenem, meropenem, gentamycin, ciprofloxacin, trimethoprim/sulfamethoxazole, tigecycline, and colistin. A broth microdilution test confirmed the colistin resistance. Conventional PCR and quantitative real-time PCR investigations revealed the presence of adeB, adeR, and adeS, while mcr-1 was not detected. A MIC of 0.38 µg/mL and 0.25 µg/mL was recorded before and after exposure to an AdeABC efflux pump inhibitor. The whole-genome sequence analysis of antimicrobial resistance-associated genes detected beta-lactam: blaOXA-66; blaOXA-23; blaADC-25; blaADC-73; blaA1; blaA2, and blaMBL; aminoglycoside: aph(6)-Id; aph(3″)-Ib; ant(3″)-IIa and armA) and a colistin resistance-associated gene lpsB. The whole-genome sequence virulence analysis revealed a biofilm formation system and cell–cell adhesion-associated genes: bap, bfmR, bfmS, csuA, csuA/B, csuB, csuC, csuD, csuE, pgaA, pgaB, pgaC, and pgaD; and quorum sensing-associated genes: abaI and abaR and iron acquisition system associated genes: barA, barB, basA, basB, basC, basD, basF, basG, basH, basI, basJ, bauA, bauB, bauC, bauD, bauE, bauF, and entE. A sequence type classification based on the Pasteur scheme revealed that the isolate belongs to sequence type ST2. Conclusions: The mosaic of the virulence factors coupled with the resistance-associated genes and the phenotypic resistance profile highlights the risk that this strain is at this South African tertiary health facility. Full article
(This article belongs to the Special Issue Colistin Resistance: The Need for a One Health Approach)
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9 pages, 271 KiB  
Article
Low Level of Colistin Resistance and mcr Genes Presence in Salmonella spp.: Evaluation of Isolates Collected between 2000 and 2020 from Animals and Environment
by Fabrizio Bertelloni, Giulia Cagnoli, Barbara Turchi and Valentina Virginia Ebani
Antibiotics 2022, 11(2), 272; https://doi.org/10.3390/antibiotics11020272 - 19 Feb 2022
Cited by 7 | Viewed by 2221
Abstract
Salmonellosis is one of the most important zoonoses in Europe and the world. Human infection may evolve in severe clinical diseases, with the need for hospitalization and antimicrobial treatment. Colistin is now considered an important antimicrobial to treat infections from multidrug- resistant Gram-negative [...] Read more.
Salmonellosis is one of the most important zoonoses in Europe and the world. Human infection may evolve in severe clinical diseases, with the need for hospitalization and antimicrobial treatment. Colistin is now considered an important antimicrobial to treat infections from multidrug- resistant Gram-negative bacteria, but the spreading of mobile colistin-resistance (mcr) genes has limited this option. We aimed to evaluate colistin minimum inhibitory concentration and the presence of mcr (mcr-1 to mcr-9) genes in 236 Salmonella isolates previously collected from different animals and the environment between 2000 and 2020. Overall, 17.79% of isolates were resistant to colistin; no differences were observed in relation to years of isolation (2000–2005, 2009–2014, and 2015–2020), Salmonella enterica subspecies (enterica, salamae, diarizonae, and houtenae), origin of samples (domestic animals, wildlife, and environment), or animal category (birds, mammals, and reptiles); only recently isolated strains from houseflies showed the most resistance. Few isolates (5.93%) scored positive for mcr genes, in particular for mcr-1, mcr-2, mcr-4, mcr-6, and mcr-8; furthermore, only 2.54% of isolates were mcr-positive and colistin-resistant. Detected resistance to colistin was equally distributed among all examined Salmonella isolates and not always related to the presence of mcr genes. Full article
(This article belongs to the Special Issue Colistin Resistance: The Need for a One Health Approach)
10 pages, 1513 KiB  
Article
Genomic Changes within a Subset of IncI2 Plasmids Associated with Dissemination of mcr-1 Genes and Other Important Antimicrobial Resistance Determinants
by Nicole Ricker, Gabhan Chalmers, Elli Whalen, Heather K. Allen and Richard J. Meinersmann
Antibiotics 2022, 11(2), 181; https://doi.org/10.3390/antibiotics11020181 - 29 Jan 2022
Cited by 3 | Viewed by 2197
Abstract
IncI2 plasmids appear to have only recently become associated with resistance genes; however, their tendency to carry resistance to the antibiotics of last resort and their widespread distribution increase their relative importance. In this study, we describe lineages within this plasmid family that [...] Read more.
IncI2 plasmids appear to have only recently become associated with resistance genes; however, their tendency to carry resistance to the antibiotics of last resort and their widespread distribution increase their relative importance. In this study, we describe lineages within this plasmid family that have an increased likelihood of acquisition of antimicrobial resistance genes. Globally distributed mcr-1-carrying IncI2 plasmids were found to cluster with other IncI2 plasmids carrying extended-spectrum beta-lactamase genes, and separately from the non-resistant IncI2 plasmids. In addition, insertion sequence (IS) elements with no direct association with the acquired resistance genes also clustered with the resistance plasmids in the phylogenetic tree. In recognition of the biased sequencing of resistant plasmids globally, the analysis was also performed on resistant and non-resistant IncI2 plasmids sequenced in the USA through government surveillance efforts that do not rely on antibiotic selection. This analysis confirmed a distinct clustering associated with both resistance and mobile elements and identified possible genomic changes in core genes that correlate with increased acquisition of foreign DNA. This work highlights a potential genetic mechanism for increased uptake of foreign DNA within this prevalent family of plasmids. Full article
(This article belongs to the Special Issue Colistin Resistance: The Need for a One Health Approach)
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14 pages, 1286 KiB  
Article
Molecular and Genomic Insights of mcr-1-Producing Escherichia coli Isolates from Piglets
by Jonathan Rodríguez-Santiago, Nadia Rodríguez-Medina, Elsa María Tamayo-Legorreta, Jesús Silva-Sánchez, Juan Téllez-Sosa, Josefina Duran-Bedolla, Alejandro Aguilar-Vera, Alba Neri Lecona-Valera, Ulises Garza-Ramos and Celia Alpuche-Aranda
Antibiotics 2022, 11(2), 157; https://doi.org/10.3390/antibiotics11020157 - 26 Jan 2022
Cited by 3 | Viewed by 2659
Abstract
The use of colistin in food-producing animals favors the emergence and spread of colistin-resistant strains. Here, we investigated the occurrence and molecular mechanisms of colistin resistance among E. coli isolates from a Mexican piglet farm. A collection of 175 cephalosporin-resistant colonies from swine [...] Read more.
The use of colistin in food-producing animals favors the emergence and spread of colistin-resistant strains. Here, we investigated the occurrence and molecular mechanisms of colistin resistance among E. coli isolates from a Mexican piglet farm. A collection of 175 cephalosporin-resistant colonies from swine fecal samples were recovered. The colistin resistance phenotype was identified by rapid polymyxin test and the mcr-type genes were screened by PCR. We assessed the colistin-resistant strains by antimicrobial susceptibility test, pulse-field gel electrophoresis, plasmid profile, and mating experiments. Whole-Genome Sequencing data was used to explore the resistome, virulome, and mobilome of colistin-resistant strains. A total of four colistin-resistant E. coli were identified from the cefotaxime-resistant colonies. All harbored the plasmid-borne mcr-1 gene, which was located on conjugative 170-kb IncHI-2 plasmid co-carrying ESBLs genes. Thus, high antimicrobial resistance rates were observed for several antibiotic families. In the RC2-007 strain, the mcr-1 gene was located as part of a prophage carried on non-conjugative 100-kb-plasmid, which upon being transformed into K. variicola strain increased the polymyxin resistance 2-fold. The genomic analysis showed a broad resistome and virulome. Our findings suggest that colistin resistance followed independent acquisition pathways as clonal and non-genetically related mcr-1-harboring strains were identified. These E. coli isolates represent a reservoir of antibiotic resistance and virulence genes in animals for human consumption which could be potentially propagated into other interfaces. Full article
(This article belongs to the Special Issue Colistin Resistance: The Need for a One Health Approach)
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17 pages, 3111 KiB  
Article
Characterisation of Early Positive mcr-1 Resistance Gene and Plasmidome in Escherichia coli Pathogenic Strains Associated with Variable Phylogroups under Colistin Selection
by Guerrino Macori, Scott V. Nguyen, Ankita Naithani, Daniel Hurley, Li Bai, Farid El Garch, Frédérique Woehrlé, Christine Miossec, Benjamin Roques, Peadar O’Gaora, James L. Bono and Séamus Fanning
Antibiotics 2021, 10(9), 1041; https://doi.org/10.3390/antibiotics10091041 - 25 Aug 2021
Cited by 7 | Viewed by 3142
Abstract
An antibiotic susceptibility monitoring programme was conducted from 2004 to 2010, resulting in a collection of 143 Escherichia coli cultured from bovine faecal samples (diarrhoea) and milk-aliquots (mastitis). The isolates were subjected to whole-genome sequencing and were distributed in phylogroups A, B1, B2, [...] Read more.
An antibiotic susceptibility monitoring programme was conducted from 2004 to 2010, resulting in a collection of 143 Escherichia coli cultured from bovine faecal samples (diarrhoea) and milk-aliquots (mastitis). The isolates were subjected to whole-genome sequencing and were distributed in phylogroups A, B1, B2, C, D, E, and G with no correlation for particular genotypes with pathotypes. In fact, the population structure showed that the strains belonging to the different phylogroups matched broadly to ST complexes; however, the isolates are randomly associated with the diseases, highlighting the necessity to investigate the virulence factors more accurately in order to identify the mechanisms by which they cause disease. The antimicrobial resistance was assessed phenotypically, confirming the genomic prediction on three isolates that were resistant to colistin, although one isolate was positive for the presence of the gene mcr-1 but susceptible to colistin. To further characterise the genomic context, the four strains were sequenced by using a single-molecule long read approach. Genetic analyses indicated that these four isolates harboured complex and diverse plasmids encoding not only antibiotic resistant genes (including mcr-1 and bla) but also virulence genes (siderophore, ColV, T4SS). A detailed description of the plasmids of these four E. coli strains, which are linked to bovine mastitis and diarrhoea, is presented for the first time along with the characterisation of the predicted antibiotic resistance genes. The study highlighted the diversity of incompatibility types encoding complex antibiotic resistance elements such as Tn6330, ISEcp1, Tn6029, and IS5075. The mcr-1 resistance determinant was identified in IncHI2 plasmids pCFS3273-1 and pCFS3292-1, thus providing some of the earliest examples of mcr-1 reported in Europe, and these sequences may be a representative of the early mcr-1 plasmidome characterisation in the EU/EEA. Full article
(This article belongs to the Special Issue Colistin Resistance: The Need for a One Health Approach)
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16 pages, 4237 KiB  
Article
Characterisation of Colistin -Resistant Enterobacterales and Acinetobacter Strains Carrying mcr Genes from Asian Aquaculture Products
by Alžběta Kalová, Tereza Gelbíčová, Søren Overballe-Petersen, Eva Litrup and Renáta Karpíšková
Antibiotics 2021, 10(7), 838; https://doi.org/10.3390/antibiotics10070838 - 09 Jul 2021
Cited by 17 | Viewed by 2529
Abstract
Aquaculture systems are widely recognised as hotspots for horizontal gene transfer, and the need for screening for bacteria carrying antimicrobial resistance genes in aquaculture systems is becoming more important. In this study, we characterised seventeen bacterial strains (Escherichia coli, Klebsiella pneumoniae [...] Read more.
Aquaculture systems are widely recognised as hotspots for horizontal gene transfer, and the need for screening for bacteria carrying antimicrobial resistance genes in aquaculture systems is becoming more important. In this study, we characterised seventeen bacterial strains (Escherichia coli, Klebsiella pneumoniae, Acinetobacter baumannii, and A. nosocomialis) resistant to colistin originating from retailed aquaculture products imported from Vietnam to the Czech Republic. The mcr-1.1 gene was found located on plasmid types IncHI2, IncI2, and IncX4, as well as on the rarely described plasmid types IncFIB-FIC and IncFIB(K), phage-like plasmid p0111, and on the chromosome of E. coli. One E. coli strain carried the mcr-3.5 gene on IncFII(pCoo) plasmid in addition to the mcr-1.1 gene located on IncHI2 plasmid. K. pneumoniae was found to carry the mcr-1.1 and mcr-8.2 genes on IncFIA(HI1) plasmid. The mcr-4.3 gene was found on similar untypeable plasmids of A. baumannii and A. nosocomialis strains, pointing to the possible interspecies transfer of plasmids carrying the mcr-4 gene. Our results highlight that some aquaculture products of Asian origin can represent an important source of variable plasmids carrying mcr genes. The results showed an involvement of phages in the incorporation of the mcr-1 gene into plasmids or the chromosome in E. coli strains from aquaculture. The detection of E. coli with the mcr-1 gene in the chromosome points to the risks associated with the stabilisation of the mcr genes in the bacterial chromosome. Full article
(This article belongs to the Special Issue Colistin Resistance: The Need for a One Health Approach)
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14 pages, 1030 KiB  
Article
The Intestinal Carriage of Plasmid-Mediated Colistin-Resistant Enterobacteriaceae in Tertiary Care Settings
by Jan Tkadlec, Alzbeta Kalova, Marie Brajerova, Tereza Gelbicova, Renata Karpiskova, Eva Smelikova, Otakar Nyc, Pavel Drevinek and Marcela Krutova
Antibiotics 2021, 10(3), 258; https://doi.org/10.3390/antibiotics10030258 - 04 Mar 2021
Cited by 10 | Viewed by 2177
Abstract
Background: In order to estimate the prevalence of plasmid borne colistin resistance and to characterize in detail the mcr-positive isolates, we carried out a sentinel testing survey on the intestinal carriage of plasmid-mediated colistin-resistant Enterobacteriaceae in hospitalized patients. Methods: Between June 2018 [...] Read more.
Background: In order to estimate the prevalence of plasmid borne colistin resistance and to characterize in detail the mcr-positive isolates, we carried out a sentinel testing survey on the intestinal carriage of plasmid-mediated colistin-resistant Enterobacteriaceae in hospitalized patients. Methods: Between June 2018 and September 2019, 1922 faecal samples from hospitalised patients were analysed by selective culture in presence of colistin (3.5 mg/L), and in parallel by direct detection of the mcr-1 to mcr-8 genes by qPCR. The mcr-positive isolates were characterised by whole-genome sequencing. Results: The prevalence of the mcr-1 gene was 0.21% (n = 4/1922); the mcr-2 to 8 genes were not detected. The mcr-1 gene was found to be localised in the IncX4 (n = 3) and IncHI2 (n = 1) plasmid type. One Escherichia coli isolate was susceptible to colistin due to the inactivation of the mcr-1 gene through the insertion of the IS2 element; however, the colistin resistance was inducible by culture in low concentrations of colistin. One human mcr-1 positive E. coli isolate was related genetically to the mcr-1 E. coli isolate derived from turkey meat of Czech origin. Conclusions:mcr-mediated colistin resistance currently poses little threat to patients hospitalised in Czech healthcare settings. The presence of the mcr-1 gene in the human population has a possible link to domestically produced, retail meat. Full article
(This article belongs to the Special Issue Colistin Resistance: The Need for a One Health Approach)
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13 pages, 480 KiB  
Article
Genomic Characteristics of Colistin-Resistant Salmonella enterica subsp. enterica Serovar Infantis from Poultry Farms in the Republic of Serbia
by Branko Jovčić, Katarina Novović, Brankica Filipić, Maja Velhner, Dalibor Todorović, Kazimir Matović, Zoran Rašić, Sonja Nikolić, Ferenc Kiškarolj and Milan Kojić
Antibiotics 2020, 9(12), 886; https://doi.org/10.3390/antibiotics9120886 - 10 Dec 2020
Cited by 21 | Viewed by 2705
Abstract
The antimicrobial susceptibility testing was conducted on 174 single isolates from poultry farms in Serbia and it was determined that seven Salmonella spp. were multidrug resistant. Sixteen serotypes were detected, but only serotype Infantis confirmed reduced susceptibility to colistin. Seven colistin resistant Salmonella [...] Read more.
The antimicrobial susceptibility testing was conducted on 174 single isolates from poultry farms in Serbia and it was determined that seven Salmonella spp. were multidrug resistant. Sixteen serotypes were detected, but only serotype Infantis confirmed reduced susceptibility to colistin. Seven colistin resistant Salmonella Infantis were studied in detail using the WGS approach. Three sequence types were identified corresponding to different epizootiology region. The isolate from the Province of Vojvodina 3842 and isolates from Jagodina (92 and 821) are represented by the sequence type ST413 and ST11, respectively. Four isolates from Kraljevo are ST32, a common S. Infantis sequence type in humans, poultry and food. The fosfomycin resistance gene fosA7 in isolate 3842 and the vgaA gene in isolate 8418/2948 encoding resistance to pleuromutilins were reported for the first time in serovar Infantis. The changes in relative expression of the phoP/Q, mgrB and pmrA/B genes were detected. Single nucleotide polymorphisms of the pmrB gene, including transitions Val164Gly or Val164Met, and Arg92Pro are described. Analyses of quinolone resistance determining region revealed substitutions Ser83Tyr in GyrA protein and Thr57Ser and Ser80Arg in ParC protein. Based on WGS data, there are two major clusters among analyzed Salmonella Infantis isolates from central Serbia. Full article
(This article belongs to the Special Issue Colistin Resistance: The Need for a One Health Approach)
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11 pages, 1767 KiB  
Article
Comprehensive Statistical Evaluation of Etest®, UMIC®, MicroScan and Disc Diffusion versus Standard Broth Microdilution: Workflow for an Accurate Detection of Colistin-Resistant and Mcr-Positive E. coli
by Isidro García-Meniño, Pilar Lumbreras, Pablo Valledor, Dafne Díaz-Jiménez, Luz Lestón, Javier Fernández and Azucena Mora
Antibiotics 2020, 9(12), 861; https://doi.org/10.3390/antibiotics9120861 - 03 Dec 2020
Cited by 8 | Viewed by 2756
Abstract
Four colistin susceptibility testing methods were compared with the standard broth microdilution (BMD) in a collection of 75 colistin-susceptible and 75 mcr-positive E. coli, including ST131 isolates. Taking BMD as reference, all methods showed similar categorical agreement rates (CA) of circa [...] Read more.
Four colistin susceptibility testing methods were compared with the standard broth microdilution (BMD) in a collection of 75 colistin-susceptible and 75 mcr-positive E. coli, including ST131 isolates. Taking BMD as reference, all methods showed similar categorical agreement rates (CA) of circa 90%, and a low number of very major errors (VME) (0% for the MicroScan system and Etest®, 0.7% for UMIC®), except for the disc diffusion assay (breakpoint ≤ 11 mm), which yielded false-susceptible results for 8% of isolates. Of note is the number of mcr-positive isolates (17.3%) categorized as susceptible (≤2 mg/L) by the BMD method, but as resistant by the MicroScan system. ST131 mcr-positive E. coli were identified as colistin-resistant by all MIC-based methods. Our results show that applying the current clinical cut-off (>2 mg/L), many mcr-positive E. coli remain undetected, while applying a threshold of >1 mg/L the sensitivity of detection increases significantly without loss of specificity. We propose two possible workflows, both starting with the MicroScan system, since it is automated and, importantly, it categorized all mcr-positive isolates as colistin-resistant. MicroScan should be followed by either BMD or MIC-based commercial methods for colistin resistance detection; or, alternatively, MicroScan, followed by PCR for the mcr screening. Full article
(This article belongs to the Special Issue Colistin Resistance: The Need for a One Health Approach)
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Other

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14 pages, 802 KiB  
Systematic Review
Dose Optimization of Colistin: A Systematic Review
by Abdul Haseeb, Hani Saleh Faidah, Saleh Alghamdi, Amal F. Alotaibi, Mahmoud Essam Elrggal, Ahmad Jamal Mahrous, Safa S. Almarzoky Abuhussain, Najla A. Obaid, Manal Algethamy, Abdullmoin AlQarni, Asim A. Khogeer, Zikria Saleem and Aziz Sheikh
Antibiotics 2021, 10(12), 1454; https://doi.org/10.3390/antibiotics10121454 - 26 Nov 2021
Cited by 11 | Viewed by 6756
Abstract
Colistin is considered a last treatment option for multi-drug and extensively resistant Gram-negative infections. We aimed to assess the available data on the dosing strategy of colistin. A systematic review was performed to identify all published studies on the dose optimization of colistin. [...] Read more.
Colistin is considered a last treatment option for multi-drug and extensively resistant Gram-negative infections. We aimed to assess the available data on the dosing strategy of colistin. A systematic review was performed to identify all published studies on the dose optimization of colistin. Grey literature and electronic databases were searched. Data were collected in a specified form and the quality of the included articles was then assessed using the Newcastle-Ottawa scale for cohort studies, the Cochrane bias tool for randomized clinical trials (RCT), and the Joanna Briggs Institute (JBI) critical checklist for case reports. A total of 19 studies were included, of which 16 were cohort studies, one was a RCT, and two were case reports. A total of 18 studies proposed a dosing regimen for adults, while only one study proposed a dosing schedule for pediatric populations. As per the available evidence, a loading dose of 9 million international units (MIU) of colistin followed by a maintenance dose of 4.5 MIU every 12 h was considered the most appropriate dosing strategy to optimize the safety and efficacy of treatment and improve clinical outcomes. This review supports the administration of a loading dose followed by a maintenance dose of colistin in severe and life-threatening multi-drug Gram-negative bacterial infections. Full article
(This article belongs to the Special Issue Colistin Resistance: The Need for a One Health Approach)
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