Klebsiella pneumoniae: development of carbapenem resistance due to acquisition of blaNDM-1 during antimicrobial therapy in twin infants with pneumonia

Autor: Junying eZhu, Baixing eDing, Xiaogang eXu, Demei eZhu, fan eYang, Hong eZhang, Fupin eHu
Jazyk: angličtina
Rok vydání: 2015
Předmět:
Zdroj: Frontiers in Microbiology, Vol 6 (2015)
Druh dokumentu: article
ISSN: 1664-302X
DOI: 10.3389/fmicb.2015.01399
Popis: Objectives: To identify the mechanism of in vivo development of carbapenem resistance in Klebsiella pneumoniae.Methods: Seven sequential isolates of K. pneumoniae were obtained from twin infants with pneumonia. Antimicrobial susceptibility testing was performed by agar dilution. Carbapenemases including KPC and ML were initially screened using phenotypic methods, and carbapenemase-encoding genes were identified by PCR and amplicon sequencing. Plasmids of all clinical isolates and the conjugants of resistant isolates were estimated by S1 pulsed-field gel electrophoresis (PFGE). Molecular typing were conducted by PFGE of XbaI-digested genomic DNA and multilocus sequence typing (MLST). Results: For old brother, the first and third isolates were susceptible to meropenem, whereas the second and fourth isolates were resistant (MICs 16 mg/L). The first and second isolates from the young brother were susceptible to meropenem whereas the third isolate was resistant. All the resistant isolates produced NDM-1 metallo--lactamase. PFGE of XbaI-digested DNA revealed identical patterns for all the 7 isolates. All the isolates had the same sequence type named sequence type 37 (ST37). Conclusions: To our knowledge, this is the first documented case of development of carbapenem resistance in vivo mediated by NDM-1 metallo-b-lactamase in K. pneumoniae during treatment of pneumonia with meropenem.
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