MCR-1.6, a New MCR Variant Carried by an IncP Plasmid in a Colistin-Resistant Salmonella enterica Serovar Typhimurium Isolate from a Healthy Individual

Lü, Xin; Hu, Yongfei; Luo, Ming‐Cheng; Zhou, Haijian; Wang, Xiaoxun; Du, Yu; Li, Zhenpeng; Xu, Jialiang; Zhu, Baoli; Xu, Xuebin; Kan, Biao

doi:10.1128/aac.02632-16

Cited by 56 publications

(45 citation statements)

References 26 publications

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“…These two strains were isolated from pig and diarrhea patients, respectively, implying that mutations may be in response to antibiotic selection and certain environmental stresses. Some researchers have also detected variants of the mcr-1 gene from bacteria isolated in environment or healthy individuals (Lu et al, 2017). In addition, three strains with the mcr-1 gene were found to be sensitive to polymyxins, suggesting that the gene does not play a role in certain strains (Quan et al, 2017), which may be related to the metabolism of the strains.…”

Section: Discussionmentioning

confidence: 99%

Retrospective Screening and Analysis of mcr-1 and blaNDM in Gram-Negative Bacteria in China, 2010–2019

Fan

Duan

et al. 2020

Front. Microbiol.

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Currently, Gram-negative bacteria have developed multidrug and broad-spectrum drug resistance, and the numbers of species and strains carrying mcr or bla NDM genes are increasing. In this study, mcr-1 and bla NDM distribution of 12,858 Gramnegative bacteria isolated from wildlife, patients, livestock, poultry and environment in 14 provinces of China from 2010 to 2019 and the antibiotics resistance in regard to polymyxins (polymyxin B and colistin) and carbapenems of positive strains were investigated. A total of 70 strains of 10 species carried the mcr-1 gene, positive rates of patients, livestock and poultry, and environmental strains were 0.62% (36/5,828), 4.07% (29/712), 5.43% (5/92), respectively. Six strains of 3 species carrying the bla NDM gene all came from patients 0.10% (6/5,828). Two new mcr-1 gene variants (GenBank: MK965883, MK965884) were identified, one of which contains premature stop codon. The drug susceptibility results showed that all mcr-1 carriers were sensitive to carbapenems, among which, 66 strains were resistant and 4 were sensitive to polymyxins. The strains with the bla NDM gene had different degrees of resistance to carbapenems and were sensitive to polymyxins. The findings that species carrying mcr-1 or bla NDM genes were limited and mostly normal flora of opportunistic or low pathogenic organisms indicated that transfer of mcr-1 and bla NDM genes between bacteria was relatively limited in China. The none detection among wildlife compared with other sources supports the speculation that the emergence of and increase in polymyxins and carbapenem-resistant strains was mainly related to the selective pressure of antibiotics.

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Section: Discussionmentioning

confidence: 99%

Retrospective Screening and Analysis of mcr-1 and blaNDM in Gram-Negative Bacteria in China, 2010–2019

Fan

Duan

et al. 2020

Front. Microbiol.

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“…Currently, 22 functional genetic variants of mcr-1 have been assigned [75][76][77][78][79][80][81][82], including mcr-1.1 [35], mcr-1.2 [83], mcr-1.3 [84], mcr-1.4 [85], mcr-1.5 [86], mcr-1.6 [87], mcr-1.7 [85], mcr-1.8 [43], mcr-1.9 [88], mcr-1.10 [75], mcr-1.11 [89], mcr-1.12 [43], mcr-1.13 [90], mcr-1.14 [71], and mcr-1.15 [91], while the other genetic variants from mcr-1.16 to mcr-1.22, were uploaded to NCBI GenBank (https://www.ncbi. nlm.nih.gov/nuccore/NG_065944.1).…”

Section: Plasmid-mediated Resistance To Polymyxinsmentioning

confidence: 99%

Colistin and its role in the Era of antibiotic resistance: an extended review (2000–2019)

Ahmed

Zhong

Cong

et al. 2020

Emerging Microbes & Infections

478

383

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Increasing antibiotic resistance in multidrug-resistant (MDR) Gram-negative bacteria (MDR-GNB) presents significant health problems worldwide, since the vital available and effective antibiotics, including; broad-spectrum penicillins, fluoroquinolones, aminoglycosides, and β-lactams, such as; carbapenems, monobactam, and cephalosporins; often fail to fight MDR Gram-negative pathogens as well as the absence of new antibiotics that can defeat these "superbugs". All of these has prompted the reconsideration of old drugs such as polymyxins that were reckoned too toxic for clinical use. Only two polymyxins, polymyxin E (colistin) and polymyxin B, are currently commercially available. Colistin has re-emerged as a last-hope treatment in the mid-1990s against MDR Gram-negative pathogens due to the development of extensively drug-resistant GNB. Unfortunately, rapid global resistance towards colistin has emerged following its resurgence. Different mechanisms of colistin resistance have been characterized, including intrinsic, mutational, and transferable mechanisms. In this review, we intend to discuss the progress over the last two decades in understanding the alternative colistin mechanisms of action and different strategies used by bacteria to develop resistance against colistin, besides providing an update about what is previously recognized and what is novel concerning colistin resistance.

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“…Recently, the MCR-2 protein (538 amino acids long, 81% amino acid identity with MCR-1) was identified in Belgium from colistin-resistant E. coli (16). Additionally, the MCR-1.2 and MCR-1.3 variants (both exhibiting single amino acid substitutions versus MCR-1) were identified in Italy and China, respectively (17,18). Several plasmid types carrying the mcr-1 gene, belonging to the IncI2, IncHI2, or IncX4 incompatibility groups, have been identified (8,10,12).…”

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confidence: 99%

Moraxella Species as Potential Sources of MCR-Like Polymyxin Resistance Determinants

Kieffer

Nordmann

Poirel

2017

Antimicrob Agents Chemother

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Plasmid-mediated resistance to polymyxins mediated by the MCR-1/2 determinants has been reported in Enterobacteriaceae worldwide. Using PCR-based and cloning strategies, a series of Moraxella spp. were screened for mcr-like genes. Moraxella spp. that are mainly animal pathogens but may also be human pathogens were identified as potential reservoirs of mcr-like genes.KEYWORDS polymyxin, plasmid, resistance, reservoir, animal, MCR R esistance to polymyxins in Enterobacteriaceae results mostly from chromosomal mutations in genes involved in modification of lipopolysaccharide (LPS) (1, 2). In particular, it has been shown that mutations, truncations, or insertions into genes encoding LPS-modifying enzymes may be responsible for acquired resistance to polymyxins in Enterobacteriaceae (1, 3, 4), Acinetobacter baumannii, and Pseudomonas aeruginosa (1, 5). However, the plasmid-mediated polymyxin resistance determinant MCR-1 was recently found in Escherichia coli and Klebsiella pneumoniae isolates recovered from humans and animals in China (6). The mcr-1 gene has been reported worldwide in other enterobacterial genera, including Enterobacter, Salmonella, and Shigella (7-11). This resistance was identified in Enterobacteriaceae isolated from various animal species, including cattle, chicken, and pigs (12-14), and from river samples and vegetables (15).MCR-1 is a 541-amino-acid phosphoethanolamine transferase that adds phosphoethanolamine to the lipid A moiety of LPS, leading to a more cationic LPS structure and consequently to resistance to polymyxins (6). Recently, the MCR-2 protein (538 amino acids long, 81% amino acid identity with MCR-1) was identified in Belgium from colistin-resistant E. coli (16). Additionally, the MCR-1.2 and MCR-1.3 variants (both exhibiting single amino acid substitutions versus MCR-1) were identified in Italy and China, respectively (17,18). Several plasmid types carrying the mcr-1 gene, belonging to the IncI2, IncHI2, or IncX4 incompatibility groups, have been identified (8,10,12). In addition, the mcr-1.2 and mcr-2 genes were found on IncX4 plasmid scaffolds (16,17).It is often suggested that animals treated with polymyxins represent a significant reservoir of polymyxin-resistant Gram-negative isolates, particularly MCR-producing isolates (19). In fact, polymyxins are heavily used in veterinary medicine, and Europeans, particularly in Spain and Italy, have a high consumption of those antibiotics for food-producing animals (20). The frequent identification of MCR-1-producing isolates from animals further supports the hypothesis that the animal world might be the primary source of this resistance determinant.

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MCR-1.6, a New MCR Variant Carried by an IncP Plasmid in a Colistin-Resistant Salmonella enterica Serovar Typhimurium Isolate from a Healthy Individual

Cited by 56 publications

References 26 publications

Retrospective Screening and Analysis of mcr-1 and blaNDM in Gram-Negative Bacteria in China, 2010–2019

Retrospective Screening and Analysis of mcr-1 and blaNDM in Gram-Negative Bacteria in China, 2010–2019

Colistin and its role in the Era of antibiotic resistance: an extended review (2000–2019)

Moraxella Species as Potential Sources of MCR-Like Polymyxin Resistance Determinants

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