KPC-157 and KPC-181 carbapenemases produced by Citrobacter freundii ST522 and Klebsiella pneumoniae ST258 isolated from wastewater

Author(s)

Furlan, Joao Pedro Rueda ; Bueno, Giovanna Carrasco ; Sousa-Carmo, Rubens Renato ; Silva, Renan Lourenco Oliveira ; Barbosa, Mikaela Renata Funada ; Sato, Maria Ines Zanoli ; Brunetti, Florencia ; Power, Pablo ; Lincopan, Nilton ; Schenkman, Sergio

• Document type: Journal article
• Source: MOLECULAR BIOLOGY REPORTS; v. 52, n. 1, p. 7-pg., 2025-07-11.

Abstract

BackgroundWhile novel KPC variants continue to emerge among clinically relevant Enterobacterales from hospital settings, their occurrence in impacted aquatic environments has been poorly investigated. We hereby report KPC-157 and KPC-181, allelic variants of KPC-2, produced by Citrobacter freundii and Klebsiella pneumoniae isolated from wastewater in Brazil.MethodsAntimicrobial susceptibility was determined by disk diffusion and broth microdilution, whereas carbapenemase production was evaluated by inhibitor-based methods. Genome sequencing was performed combining short-read (Illumina HiSeq) and long-read (Oxford Nanopore) technologies, with further bioinformatic analyses. In silico KPC modeling was carried out using Yasara/PyMOL. Horizontal transfer and plasmid stability were assessed by conjugation and serial passage experiments, respectively. Epidemiological tracking of KPC-2 allelic variants and KPC-bearing plasmids was performed using publicly available genomes.ResultsCarbapenem-resistant C. freundii strain M21 [sequence type (ST) 522] and K. pneumoniae strains M16 and M18 (ST258), harboring blaKPC-157 and blaKPC-181 genes, respectively, were recovered from a sewage treatment plant. KPC-157 and KPC-181 differed from KPC-2 by single amino acid substitutions (Asn132Ser and Glu275Asp, respectively) that do not affect the main kinetic behavior, preserving the classical KPC-2 resistance phenotype (i.e., carbapenem resistance and ceftazidime-avibactam susceptibility). KPC-2 allelic variants were embedded in Tn4401 transposons. KPC-157 was carried on an IncN2 plasmid, while KPC-181 was associated with an IncFIB(pQil)/IncFII(K) plasmid.ConclusionThe identification of KPC-157 and KPC-181 in wastewater highlights the role of polluted environments in harboring novel KPC variants from high-risk Enterobacterales clones and reinforces the importance of continued antimicrobial resistance surveillance beyond hospital settings. (AU)

• FAPESP's process: 21/10599-3 - The Antimicrobial Resistance Institute of São Paulo (The Aries Project)
• Grantee: Arnaldo Lopes Colombo
• Support Opportunities: Research Grants - Research, Innovation and Dissemination Centers - RIDC