Genomic Background and Phylogeny of <i>cfi</i>A-Positive <i>Bacteroides fragilis</i> Strains Resistant to Meropenem-EDTA
Background: <i>Bacteroides fragilis</i> shows high antimicrobial resistance (AMR) rates and possesses numerous AMR mechanisms. Its carbapenem-resistant strains (metallo-β-lactamase <i>cfi</i>A-positive) appear as an emergent, evolving clade. Methods: This work examines the ge...
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| Main Authors: | , , , , , , , |
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| Format: | Book |
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MDPI AG,
2021-03-01T00:00:00Z.
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| Summary: | Background: <i>Bacteroides fragilis</i> shows high antimicrobial resistance (AMR) rates and possesses numerous AMR mechanisms. Its carbapenem-resistant strains (metallo-β-lactamase <i>cfi</i>A-positive) appear as an emergent, evolving clade. Methods: This work examines the genomes, taxonomy, and phylogenetic relationships with respect to other <i>B. fragilis</i> genomes of two <i>B. fragilis</i> strains (CNM20180471 and CNM20200206) resistant to meropenem+EDTA and other antimicrobial agents. Results: Both strains possessed <i>cfi</i>A genes (<i>cfi</i>A14b and the new <i>cfi</i>A28), along with other AMR mechanisms. The presence of other efflux-pump genes, <i>mex</i>AB/<i>mex</i>JK/<i>mex</i>XY-<i>opr</i>M, <i>acr</i>EF/<i>mdt</i>EF-<i>tol</i>C, and especially <i>cus</i>R, which reduces the entry of carbapenem via the repression of porin OprD, may be related to meropenem-EDTA resistance. None of the detected insertion sequences were located upstream of <i>cfi</i>A. The genomes of these and other <i>B. fragilis</i> strains that clustered together in phylogenetic analyses did not meet the condition of >95% average nucleotide/amino acid identity, or >70% in silico genome-to-genome hybridization similarity, to be deemed members of the same species, although <1% difference in the genomic G+C content was seen with respect to the reference genome <i>B. fragilis</i> NCTC 9343T. Conclusions: Carbapenem-resistant strains may be considered a distinct clonal entity, and their surveillance is recommended given the ease with which they appear to acquire AMR. |
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| Item Description: | 10.3390/antibiotics10030304 2079-6382 |