Microbiological and Genetic Characterization of Carbapenem-Resistant Klebsiella pneumoniae Isolated From Pediatric Patients

Abstract

This manuscript reports the clinical, microbiological, and genetic characteristics of carbapenem-resistant K. pnuemoniae isolates from pediatric patients at a tertiary-care children's hospital. Although there is an extensive body of literature describing carbapenem-resistant Klebsiella infections in adults, pediatric data are comparatively limited.

Keywords: Klebsiella pneumoniae; carbapenemase; polymyxin.

Figure 1.

Pulsed-field gel electrophoresis and genotyping results of carbapenem-resistant Klebsiella pneumoniae isolates from pediatric and adult patients. XbaI chromosomal restriction patterns were analyzed to examine the genetic relatedness of pediatric and adult isolates. Isolates were genotyped by multilocus sequence typing (MLST). β-Lactamase genes bla_CTX-M, bla_SHV, bla_TEM, bla_KPC, bla_NDM, bla_VIM, bla_IMP, bla_OXA-48, porin genes ompK35 and ompK36, and transposon Tn4401 isoforms were detected by polymerase chain reaction and sequencing. Isolates from Patient C (urine, blood, and wound) and Patient A (blood) display banding patterns similar to those observed for representative adult isolates. The isolate from Patient D displays a banding pattern distinct from the other isolates. “Patient C Urine—2” represents an isolate obtained in the absence of symptoms and is similar to the prior blood, urine, and wound isolates from this patient. All pediatric isolates were ST258 and expressed either KPC-2 or 3, SHV-12, and TEM-1. All pediatric isolates were found to contain a guanine insertion at nt121 within ompK35, resulting in a stop codon at amino acid position 89 (aa89-stop). All ompK36 genes were found to be wild-type (WT). All isolates from Patient C were Tn4401a isoform, while isolates from Patient A and D were Tn4401b isoform.