Description of a new non-Tn4401 element (NTEKPC-IIe) harboured on IncQ plasmid in Citrobacter werkmanii from recreational coastal water

Abstract

ABSTRACT: Objectives: Here we describe an IncQ1-like plasmid carrying blaKPC-2 in a new non-Tn4401 element found in Citrobacter werkmanii recovered from coastal water. Methods: In vitro and in silico approaches were used to assess antimicrobial resistance determinants, as well as blaKPC-2 vicinities. Results: The LB-887 isolate showed a multidrug-resistant phenotype and was identified as C. werkmanii. Resistome analysis identified further acquired resistance determinants to β-lactams, aminoglycosides, sulphonamides/trimethoprim, tetracyclines, chloramphenicol, macrolides, rifampicin and fluoroquinolones. Plasmidome included incompatibility groups IncA, IncC2, IncR, Col and IncQ families. The blaKPC-2 was inserted on a new variant of NTEKPC-II, called here NTEKPC-IIe, carried by an InQ1-like plasmid of 7930 kb (pKPC-LB887). NTEKPC-IIe differed from NTEKPC-IId by the complete absence of ISKpn6-tnpA. The InQ1-like backbone harbouring this element had been described in Enterobacterales recovered from clinical and environmental settings. Conclusion: Unravelling genetic structures related to blaKPC dissemination in different settings may provide clues on the main forces driving evolution of this important resistance determinant. Indeed, the occurrence of blaKPC in a new NTEKPC variant from an environmental source highlights the ongoing evolution of this mobile genetic element. In addition, blaKPC carriage on a small and highly mobilizable IncQ plasmid in C. freundii complex from recreational water, similar to others found in clinical isolates, may suggest its relevance for blaKPC-2 dissemination among different compartments.

Keywords

• Small IncQ plasmid
• Carbapenemase
• KPC-2
• Genetic environment