First description of antimicrobial resistance in carbapenem-susceptible Klebsiella pneumoniae after imipenem treatment, driven by outer membrane remodeling

Abstract

Background: The emergence of carbapenem-resistant Klebsiella pneumoniae (CRKP) poses a looming threat to human health. Although there are numerous studies regarding porin alteration in association with the production of ESBLs and/or AmpC β-lactamase, a systematic study on the treatment-emergence of porins alteration in antibiotic resistance does not yet exist. The aim of this study was to investigate the underlying mechanism of resistance of K. pneumoniae during carbapenem treatment. Results: Here, we report three strains (FK-2624, FK-2723 and FK-2820) isolated from one patient before and after imipenem treatment during hospitalization. Antibiotic susceptibility testing indicated that that the first isolate, FK-2624, was susceptible to almost all tested antimicrobials, being resistant only to fosfomycin. The subsequent isolates FK-2723 and FK-2820 were multidrug resistant (MDR). After imipenem therapy, FK-2820 was found to be carbapenem-resistant. PCR and Genome Sequencing analysis indicated that oqxA, and fosA5, were identified in all three strains. In addition, FK-2624 also harbored bla SHV-187 and bla TEM-116. The bla SHV-187 and bla TEM-116 genes were not detected in FK-2723 and FK-2820. bla DHA-1 , qnrB4, aac (6′)-IIc, and bla SHV-12 , EreA2, CatA2, SulI, and tetD, were identified in both FK-2723 and FK-2820. Moreover, the genes bla DHA-1, qnrB4, aac (6′)-IIc were co-harbored on a plasmid. Of the virulence factors found in this study, ybtA, ICEKp6, mrkD, entB, iroN, rmpA2-6, wzi16 and capsular serotype K57 were found in the three isolates. The results of pairwise comparisons, multi-locus sequencing typing (MLST) and pulsed-field gel electrophoresis (PFGE) revealed high homology among the isolates. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) results showed that isolate FK-2820 lacked OmpK36, with genome sequence data validating that there was a premature stop codon in the ompK36 gene and real-time RT-PCR suggesting high turnover of the ompK36 nonsense transcript in FK-2820, with the steady-state mRNA level 0.007 relative to the initial isolate.

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

“…Strain 130002 contains three β-lactamase-encoding genes including narrow-spectrum β-lactamase gene bla SHV−187 (Tian et al, 2020) on chromosome, carbapenemase gene bla KPC−2 on a 94.9-kb IncFII plasmid of the Y6:A-:B-type (designated pKPC2_130002), and a novel bla OXA gene on a 117.8-kb plasmid containing both IncFIA and IncFII replicons (designated pOXA926_130002; Table 3). pKPC2_130002 shows the closest similarity among the sequenced plasmids to pKPC2_020019 (accession no.…”

Stepwise evolution of carbapenem-resistance, captured in patient samples and evident in global genomics of Klebsiella pneumoniae

“…Together, genotypes such as this result in a decreased concentration of carbapenem in the periplasm, which if sufficiently low, can be cleared by the action of ESBLs to generate a non-CP CRE phenotype (6). Consistent with this, we recently reported a case study where a CRE phenotype was ultimately generated by loss of porin function in a strain that expressed no recognizable carbapenemase, but which carried the blaDHA-1 gene encoding an ESBL (10).…”

“…1b). This explains the absence of detectable OmpK36 observed in immunoblots of FK-2820 (10). Mechanistically, the loss of porin function would decrease the entry of drug into the periplasm.…”

Stepwise Evolution of a Klebsiella pneumoniae Clone within a Host Leading to Increased Multidrug Resistance

“…Within-host evolution of AMR in K. pneumoniae by acquisition of an MDR plasmid and a nonsense mutation in ompK36 gene has recently been reported by Tian et al ( 26 ). Our present study also showed that the plasmid acquisition and the defect of OmpK36 contributed to the evolution of drug resistance, but we additionally identified the changes in hexuronate metabolism-related genes and atpG , which might compensate for the negative effects of the porin defect.…”