Nosocomial spread of Klebsiella pneumoniae isolates producing bla carbapenemase at a Japanese hospital.

Six Klebsiella pneumoniae clinical isolates resistant to various cephalosporins and cephamycins were identified in a Japanese general hospital, a tertiary care hospital, between November 2009 and April 2010. All K. pneumoniae isolates carried bla and bla, while 2 K. pneumoniae isolates also harbored bla. The pulsed-field gel electrophoresis patterns revealed that these 6 K. pneumoniae isolates were almost identical, suggesting their clonal relatedness. Plasmid profiles and conjugation assays revealed that these bla genes were located on similar conjugative plasmids. These data indicate that nosocomial spread caused by K. pneumoniae isolates producing bla carbapenemase occurred at a Japanese general hospital. K. pneumoniae isolate harboring bla is rarely reported in Japan, and, to the best of our knowledge, this is the second report of K. pneumoniae isolates harboring bla that occurred nosocomial spread in Japan.