''Silent'' Dissemination of Klebsiella pneumoniae Isolates Bearing K. pneumoniae Carbapenemase in a Long-term Care Facility for Children and Young Adults in Northeast Ohio.

Background. Klebsiella pneumoniae isolates harboring the K. pneumoniae carbapenemase gene (bla_KPC) are creating a significant healthcare threat in both acute and long-term care facilities (LTCFs). As part of a study conducted in 2004 to determine the risk of stool colonization with extended-spectrum cephalosporin-resistant gram-negative bacteria, 12 isolates of K. pneumoniae that exhibited nonsusceptibility to extended-spectrum cephalosporins were detected. All were gastrointestinal carriage isolates that were not associated with infection. Methods. Reassessment of the carbapenem minimum inhibitory concentrations using revised 2011 Clinical Laboratory Standards Institute breakpoints uncovered carbapenem resistance. To further investigate, a DNA microarray assay, PCR-sequencing of bla genes, immunoblotting, repetitive-sequence-based PCR (rep-PCR) and multilocus sequence typing (MLST) were performed. Results. The DNA microarray detected bla_KPC in all 12 isolates, and bla_KPC-3 was identified by PCR amplification and sequencing of the amplicon. In addition, a bla_SHV-11 gene was detected in all isolates. Immunoblotting revealed “low-level” production of the K. pneumoniae carbapenemase, and rep-PCR indicated that all bla_KPC-3-positive K. pneumoniae strains were genetically related (≥98% similar). According to MLST, all isolates belonged to sequence type 36. This sequence type has not been previously linked with bla_KPC carriage. Plasmids from 3 representative isolates readily transferred the bla_KPC-3 to Escherichia coli J-53 recipients. Conclusions. Our findings reveal the “silent” dissemination of bla_KPC-3 as part of Tn4401b on a mobile plasmid in Northeast Ohio nearly a decade ago and establish the first report, to our knowledge, of K. pneumoniae containing bla_KPC-3 in an LTCF caring for neurologically impaired children and young adults. [ABSTRACT FROM AUTHOR]