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Rapid detection and quantification of plasmid‐mediated colistin resistance genes ( mcr‐1 to mcr‐5 ) by real‐time PCR in bacterial and environmental samples
Author(s) -
Tolosi R.,
Apostolakos I.,
Laconi A.,
Carraro L.,
Grilli G.,
Cagnardi P.,
Piccirillo A.
Publication year - 2020
Publication title -
journal of applied microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.889
H-Index - 156
eISSN - 1365-2672
pISSN - 1364-5072
DOI - 10.1111/jam.14738
Subject(s) - colistin , mcr 1 , plasmid , biology , gene , microbiology and biotechnology , escherichia coli , serial dilution , polymerase chain reaction , real time polymerase chain reaction , enterobacteriaceae , genetics , antimicrobial , medicine , alternative medicine , pathology
Aim The aim of the study was to validate a rapid method to detect and quantify colistin resistance genes ( mcr‐1 to mcr‐5 ) by real‐time polymerase chain reaction (RT‐PCR) in diverse matrices. Methods and results The detection limit of two newly designed SYBR Green real‐time PCR assays for mcr‐4 and mcr‐5 and of previously published protocols for mcr‐1 to mcr‐3 was assessed using serial dilutions of reference strains. The assays could detect all five mcr genes with the lower limit of 10 2 copy numbers. Escherichia coli isolates ( n = 1062) and environmental samples ( n = 93) were tested for the presence of mcr genes. The assays enabled the detection of colistin resistance genes both in bacterial isolates and in complex environmental samples. Conclusions This method represents a set of sensitive, rapid and effective assays for the screening of colistin resistance directly from the environment. Significance and Impact of the Study Colistin is an antimicrobial commonly used in animals and has recently emerged as a last‐resort treatment in humans. Plasmid‐mediated mcr genes confer resistance to colistin and represent a major threat for public health since they can be easily disseminated through horizontal gene transfer. The rapid and sensitive detection of mcr genes is of utmost necessity.