AUTHOR=Paveenkittiporn Wantana , Kamjumphol Watcharaporn , Ungcharoen Ratchadaporn , Kerdsin Anusak 

TITLE=Whole-Genome Sequencing of Clinically Isolated Carbapenem-Resistant Enterobacterales Harboring mcr Genes in Thailand, 2016–2019

JOURNAL=Frontiers in Microbiology

VOLUME=11

YEAR=2021

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2020.586368

DOI=10.3389/fmicb.2020.586368

ISSN=1664-302X

ABSTRACT=<p>Mobile colistin-resistant genes (<italic>mcr</italic>) have become an increasing public health concern. Since the first report of <italic>mcr-1</italic> in Thailand in 2016, perspective surveillance was conducted to explore the genomic characteristics of clinical carbapenem-resistant Enterobacterales (CRE) isolates harboring <italic>mcr</italic> in 2016–2019. Thirteen (0.28%) out of 4,516 CRE isolates were found to carry <italic>mcr</italic> genes, including 69.2% (9/13) of <italic>E. coli</italic> and 30.8% (4/13) of <italic>K. pneumoniae</italic> isolates. Individual <italic>mcr-1.1</italic> was detected in eight <italic>E. coli</italic> (61.5%) isolates, whereas the co-occurrence of <italic>mcr-1.1</italic> and <italic>mcr-3.5</italic> was seen in only one <italic>E. coli</italic> isolate (7.7%). No CRE were detected carrying <italic>mcr-2, mcr-4</italic>, or <italic>mcr-5</italic> through to <italic>mcr-9</italic>. Analysis of plasmid replicon types carrying <italic>mcr</italic> revealed that IncX4 was the most common (61.5%; 8/13), followed by IncI2 (15.4%; 2/13). The minimum inhibitory concentration values for colistin were in the range of 4–16 μg/ml for all CRE isolates harboring <italic>mcr</italic>, suggesting they have 100% colistin resistance. Clermont phylotyping of nine <italic>mcr</italic>-harboring carbapenem-resistant <italic>E. coli</italic> isolates demonstrated phylogroup C was predominant in ST410. In contrast, ST336 belonged to CC17, and the KL type 25 was predominant in carbapenem-resistant <italic>K. pneumoniae</italic> isolates. This report provides a comprehensive insight into the prevalence of <italic>mcr</italic>-carrying CRE from patients in Thailand. The information highlights the importance of strengthening official active surveillance efforts to detect, control, and prevent <italic>mcr</italic>-harboring CRE and the need for rational drug use in all sectors.</p>