Novel patterns in the molecular epidemiology of KPC-producing Klebsiella pneumoniae in Tucuman, Argentina

Background: In Argentina, there has been an abrupt increase in KPC-2-producing Klebsiella pneumoniae (K. pneumoniae). Tucuman is a multi-border area, so the rapid dissemination of carbapenem-resistant K. pneumoniae is a clinically relevant problem for the region. Objectives: This study aimed to investigate the epidemiological and molecular patterns of KPC-producing K. pneumoniae clinical isolates collected from different hospitals in Tucuman. Methods: Carbapenem-resistant K. pneumoniae strains were sequentially and uniquely collected during two time periods. Antibiotic susceptibility was determined by the automated Vitex (R) system and using the standard agar dilution test. Multilocus sequence typing and pulsed-field electrophoresis were used for epidemiological analysis. The genetic structures around bla(KPC) and the encoding genes of extended-spectrum beta-lactamases were detected by polymerase chain reaction and sequencing. Plasmids were analysed by conjugation and using the plasmid relaxase gene-typing method. Results: All 37 isolates were multidrug resistant, and the bla(KPC-2) gene was confirmed in all of them. In 17 isolates (45.9%), the bla(CTX-M-2) gene was also amplified, as well as bla(SHV-2) in five isolates (13.5%) and bla(CTX-M-2)/bla(SHV-2) in four isolates (10.8%). The molecular epidemiology of the bla(KPC-2) gene has resulted in it being associated with an IncL/M transferable plasmid disseminating in various sequence types (STs) (ST17, ST556, ST342, ST147, ST461, ST65, ST15 and ST70), and in a new genetic environment with a 764-bp deletion in the ISKpn7-bla(KPC) region. Conclusions: These findings contribute to the understanding of the great diversity of the bla(KPC-2)-carrying genetic platforms. (C) 2019 International Society for Chemotherapy of Infection and Cancer. Published by Elsevier Ltd. All rights reserved.