Genomic characterization of a KPC-23-producing Klebsiella pneumoniae ST258 clinical isolate resistant to ceftazidime-avibactam

Abstract

Objectives: We characterized the first ceftazidime-avibactam-resistant KPC-producing-Klebsiella pneumoniae clinical isolate detected in Greece, before the introduction of ceftazidime-avibactam in clinical practice. Methods: K. pneumoniae KP-90 was isolated from a hospitalized patient in Thessaloniki during a nationwide surveillance study conducted between 2014 and 2016. Antimicrobial susceptibility was tested against a panel of agents. Whole-genome sequencing (Ion Torrent TM platform) of the isolate was carried out to identify the acquired resistance genes and mutations that were associated with ceftazidime-avibactam resistance. Results: The K. pneumoniae isolate belonged to multilocus sequence type ST258 and harboured bla KPC-23 as the only carbapenemase gene. The isolate had a minimum inhibitory concentration (MIC) of 16 mg/L to ceftazidime-avibactam and was highly resistant to imipenem, meropenem (MICs, 512 mg/L) and ceftazidime (MIC, >1024 mg/L). bla KPC-23 was detected on a Tn4401a transposon, located on a pKPQILtype plasmid. A non-functional outer membrane protein OmpK35 and an OmpK36 variant that had been previously associated with K. pneumoniae isolates of ST258 were detected. Transformation studies with Escherichia coli TOP10 showed that KPC-23 offered similar carbapenem MICs as KPC-2 and KPC-3. However, KPC-23 conferred a four-fold higher ceftazidime MIC (>1024 mg/L), which in the presence of avibactam was reduced (>7-fold) to 8 mg/L, which is just within the limit of the susceptibility breakpoint. Conclusions: Ceftazidime-avibactam resistance in a KPC-23-producing K. pneumoniae clinical isolate was due to increased ceftazidime hydrolysis and was likely enhanced by OmpK35 porin deficiency. I. Galani,

Phenotypic, Biochemical, and Genetic Analysis of KPC-41, a KPC-3 Variant Conferring Resistance to Ceftazidime-Avibactam and Exhibiting Reduced Carbapenemase Activity

“…The bla KPC-41 -positive K. pneumoniae UM belonged to ST395, although the previously reported KPC producers exhibiting CZA resistance belonged to ST258 (6), ST307 (3), and ST1519 (11). It is noteworthy that an outbreak caused by a KPC-3-producing K. pneumoniae ST395 isolate (susceptibility to CZA not reported) has been reported in a neonatal intensive care unit in Palermo, Italy, and in our study the patient carrying K. pneumoniae UM also originated from Sicily (12).…”

“…In contrast, the amino acid insertion identified in KPC-41 was distantly located from the omega loop. Nevertheless, amino acid substitutions distantly located from the omega loop but leading to resistance to CZA have been also reported among KPC variants, such as KPC-8 (Val240Gly and His274Tyr) (6) and KPC-23 (Val240Ala and His274Tyr) (11).…”

Outbreak of KPC-2-producing Klebsiella pneumoniae endowed with ceftazidime-avibactam resistance mediated through a VEB-1-mutant (VEB-25), Greece, September to October 2019

“…CZA demonstrates high in vitro activity against nonmetallo-β-lactamase-producing K. pneumoniae strains in Greece [8]. To date, there are two reports on sporadic cases of CZA resistant K. pneumoniae from Greece, due to the production of KPC-23 [10], or VEB-25 [5]. In the present study, we provide further evidence that CZA resistance may emerge through evolution of bla VEB-1 with the detection of a bla VEB-25 -harbouring strain causing a hospital outbreak and another strain endowed with bla VEB-14 in a single hospitalised patient.…”

“…Whole genome sequencing (WGS) analysis, performed as described previously [10], revealed that both bla VEB- 14 and bla VEB-25 were carried on conjugative plasmids of IncA/C2 incompatibility group. bla VEB14 and bla VEB-25 were present as the first gene cassette of an integron that also included an array of aadB, arr2, cmlA1, bla OXA-10 , and aadA1 cassettes.…”

“…The first pulsotype included only the KP121, isolated in November 2018, while all the strains isolated in the period September-October 2019, belonged to one clone (second pulsotype). Based on WGS [10], KP121 belonged to sequence type (ST)39 and capsular type KL23 (wzc: 24; wzi: 83), while the outbreak strain belonged to clonal lineage ST147 and capsular type KL64 (wzc: 64; wzi: 64).…”