New sequence type in multidrug-resistant Klebsiella pneumoniae harboring the bla NDM-1 -encoding gene in Brazil

Abstract

Objectives: The aim of this study was to investigate the bla NDM gene, pathogenic potential, and antimicrobial resistance of clinical isolates of carbapenem-resistant Klebsiella pneumoniae isolated from patients admitted to the University Hospital of Londrina between January 2014 and March 2017. Methods: bla NDM-1 and virulence genes were investigated using conventional PCR methods Antimicrobial susceptibility testing was performed by disk diffusion method according to the Clinical and Laboratory Standards Institute guidelines of 2017. Clonal relationships of the New Delhi metallo-β-lactamase (NDM)-positive isolates were determined by enterobacterial repetitive intergenic consensus (ERIC)-PCR and multilocus sequence typing (MLST). Results: A total of 825 K. pneumoniae were identified, with four isolates (Kp6408, Kp6410, Kp6411, and Kp6715) presenting the bla NDM-1 gene. All NDM-1-producing isolates showed co-production of bla KPC-2 and bla TEM genes and also the virulence genes kfu, entB, mrkD, and fimH. Three isolates (Kp6408, Kp6410, and Kp6715) were classified as multidrug-resistant (MDR) and one (Kp6411) as extensively drug-resistant (XDR). ERIC-PCR analyses demonstrated that the isolates shared about 60% genetic similarity. MLST revealed four different sequence types (STs), described for the first time in Brazil, with two novel STs described in this study: ST3371 and ST3372. Conclusion: This study reports the identification of NDM-1 associated with KPC and virulence genes in four MDR K. pneumoniae with STs first described in Brazil.