Overexpression of blaSHV-12 caused by tandem amplification contributed to ceftazidime/avibactam resistance in hypervirulent and carbapenem-resistant Klebsiella pneumoniae

We identified a novel ceftazidime/avibactam (CAZ/AVI) resistance mechanism in endemic sequence type 11 hypervirulent and carbapenem-resistant Klebsiella pneumoniae isolated from a patient who had not been exposed CAZ/AVI. Overexpression of blaSHV-12 caused by tandem gene amplification contributed to CAZ/AVI resistance instead of the carriage of blaKPC-2. Enhanced genomic surveillance is essential to identify emerging variants.