AUTHOR=Liu Lina , Feng Yu , Wei Li , Xiao Yuling , Zong Zhiyong 

TITLE=KPC-2-Producing Carbapenem-Resistant Klebsiella pneumoniae of the Uncommon ST29 Type Carrying OXA-926, a Novel Narrow-Spectrum OXA β-Lactamase

JOURNAL=Frontiers in Microbiology

VOLUME=12

YEAR=2021

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2021.701513

DOI=10.3389/fmicb.2021.701513

ISSN=1664-302X

ABSTRACT=<p>We isolated and characterized a carbapenem-resistant <italic>Klebsiella pneumoniae</italic> (CRKP) clinical strain from blood carrying a novel <italic>bla</italic><sub>OXA</sub> gene, <italic>bla</italic><sub>OXA–926</sub>, and belonging to ST29, an uncommon CRKP type. The strain, 130002, was genome sequenced using both short- and long-read sequencing and has a 94.9-kb self-transmissible IncFII plasmid carrying <italic>bla</italic><sub>KPC–2</sub>. <italic>K. pneumoniae</italic> genomes of the ST29 complex (ST29 and its single-allele variants) were retrieved and were subjected to single nucleotide polymorphism-based phylogenomic analysis. A total of 157 genomes of the ST29 complex were identified. This complex is commonly associated with extended-spectrum β-lactamase-encoding genes, in particular, <italic>bla</italic><sub>CTX–M–15</sub> but rarely has carbapenemase genes. The novel plasmid-encoded β-lactamase-encoding gene <italic>bla</italic><sub>OXA–926</sub> was identified on a 117.8-kb IncFIA-IncFII plasmid, which was transferrable in the presence of the <italic>bla</italic><sub>KPC–2</sub>-carrying plasmid. <italic>bla</italic><sub>OXA–926</sub> was cloned and MICs of β-lactams in the transformants were determined using microdilution. OXA-926 has a narrow spectrum conferring reduced susceptibility only to piperacillin, piperacillin-tazobactam, and cephalothin. Avibactam cannot fully inhibit OXA-926. <italic>bla</italic><sub>OXA–926</sub> and its variants have been seen in <italic>Klebsiella</italic> strains in Asia and Brazil. OXA-926 is the closest in sequence identity (89.9%) to a chromosome-encoding OXA-type enzyme of <italic>Variovorax guangxiensis</italic>. In conclusion, OXA-926 is novel plasmid-borne narrow-spectrum β-lactamase that cannot be fully inhibited by avibactam. It is likely that <italic>bla</italic><sub>OXA–926</sub> originates from a species closely related to <italic>V</italic>. <italic>guangxiensis</italic> and was introduced into <italic>Klebsiella</italic> &gt; 10 years ago.</p>