Reversion of KPC-114 to KPC-2 in ceftazidime-avibactam- resistant/meropenem-susceptible Klebsiella pneumoniae ST11 is related to low mutation rates

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Pariona, Jesus G. M. ; Vasquez-Ponce, Felipe ; Becerra, Johana ; Goncalves, Thais Martins ; Pariona, Eva M. M. ; Madueno, Fabio T. ; Esposito, Fernanda ; de Lima, Aline V. ; Sampaio, Jorge L. Mello ; Galhardo, Rodrigo S. ; Lincopan, Nilton

• Document type: Journal article
• Source: MICROBIOLOGY SPECTRUM; v. 12, n. 10, p. 8-pg., 2024-08-27.

Abstract

Klebsiella pneumoniae strains that produce Klebsiella pneumoniae Carbapenemase (KPC) variants displaying resistance to ceftazidime-avibactam (CZA) often remain susceptible to meropenem (MEM), suggesting a potential therapeutic use of this carbapenem antibiotic. However, in vitro studies indicate that these sorts of strains can mutate becoming MEM-resistant, raising concerns about the effectiveness of carbapenems as treatment option. We have studied mutation rates occurring from the reversion of MEM-susceptible KPC-114 to MEM-resistant KPC-2, in CZA-resistant K. pneumoniae belonging to ST11. Two-step fluctuation assays (FAs) were conducted. In brief, initial cultures of KPC-114-producing K. pneumoniae showing 1 mu g/mL MEM MIC were spread on Mueller-Hinton agar plates containing 2-8 mu g/mL MEM. A second step of FA, at 4-16 mu g/mL MEM was performed from a mutant colony obtained at 2 mu g/mL MEM. Mutation rates were calculated using maximum likelihood estimation. Parental and mutant strains were sequenced by Illumina NextSeq, and mutations were predicted by variant-calling analysis. At 8 mu g/mL MEM, mutants derived from parental CZA-resistant (MIC >= 64 mu g/mL)/MEM-susceptible (MIC = 1 mu g/mL) KPC-114-positive K. pneumoniae exhibited an accumulative mutation rate of 3.05 x 10(-19) mutations/cell/generation, whereas at 16 mu g/mL MEM an accumulative mutation rate of 1.33 x 10(-19) mutations/cell/generation resulted in the reversion of KPC-114 (S181_P182 deletion) to KPC-2. These findings highlight that the reversion of MEM-susceptible KPC-114 to MEM-resistant KPC-2, in CZA-resistant K. pneumoniae ST11 is related to low mutation rates suggesting a low risk of therapeutic failure. In vivo investigations are necessary to confirm the clinical potential of MEM against CZA-resistant KPC variants. IMPORTANCE The emergence of ceftazidime-avibactam (CZA) resistance among carbapenem-resistant Klebsiella pneumoniae is a major concern due to the limited therapeutic options. Strikingly, KPC mutations mediating CZA resistance are generally associated with meropenem susceptibility, suggesting a potential therapeutic use of this carbapenem antibiotic. However, the reversion of meropenem-susceptible to meropenem-resistant could be expected. Therefore, knowing the mutation rate related to this genetic event is essential to estimate the potential use of meropenem against CZA-resistant KPC-producing K. pneumoniae. In this study, we demonstrate, in vitro, that under high concentrations of meropenem, reversion of KPC-114 to KPC-2 in CZA-resistant/meropenem-susceptible K. pneumoniae belonging to the global high-risk ST11 is related to low mutation rates. (AU)

• FAPESP's process: 19/15578-4 - Virulome and pathogenicity of carbapenem- and polymyxin-resistant priority pathogens
• Grantee: Fernanda Ribeiro dos Santos Esposito
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 23/18292-0 - BiocinBR: Bacteriocin research platform to combat pathogens resistant to critical priority antimicrobials in Brazil
• Grantee: Zuleyma Johana Becerra Tellez
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 20/08224-9 - OneBR (One Health Brazilian Resistance): integrated genomic database for surveillance, diagnosis, management and treatment of antimicrobial resistance in the human-animal-environment interface, in Brazil
• Grantee: Nilton Erbet Lincopan Huenuman
• Support Opportunities: Regular Research Grants