Hospital-wide outbreaks of carbapenem-resistant Enterobacteriaceae horizontally spread through a clonal plasmid harbouring blaIMP-1 in children’s hospitals in Japan

Carbapenem resistance is primarily conferred by carbapenemases, enzymes that hydrolyse carbapenems. While KPC, NDM and OXA-48 are the most commonly identified carbapenemases,1 IMP carbapenemases have been frequently reported in Japan and Australia.2,3 In Japan, IMP-1 producers have disseminated predominantly in eastern areas, including Tokyo,4,5 and western areas, including Kyushu,6 while IMP-6 producers have been exclusively found in central areas, including Osaka,3 despite heavy movement of people between cities (Figure S1, available as Supplementary data at JAC Online). Herein, we report two consecutive outbreaks of carbapenem-resistant Enterobacteriaceae (CRE) isolates carrying blaIMP-1 in a children’s hospital in Osaka, Japan. In September 2018, a Klebsiella pneumoniae isolate producing IMP-1 was isolated from the urine of a 1-month-old patient (patient A) in the hospital, who was born with and hospitalized for prune belly syndrome without carbapenem treatment. CRE surveillance revealed that two more...