期刊
JOURNAL OF ANTIMICROBIAL CHEMOTHERAPY
卷 72, 期 11, 页码 3035-3042出版社
OXFORD UNIV PRESS
DOI: 10.1093/jac/dkx234
关键词
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资金
- National Institutes of Health [R21AI107302]
- National Natural Science Foundation of China [81673479]
- [U01AI124302]
- [U19AI110820]
- [R01AI123820]
- [R01AI104895]
- [R21AI123747]
Background: Colistin resistance in Klebsiella pneumoniae typically involves inactivation or mutations of chromosomal genes mgrB, pmrAB or phoPQ, but data regarding consequent modifications of LPS are limited. Objectives: To examine the sequences of chromosomal loci implicated in colistin resistance and the respective LPS-derived lipid A profiles using 11 pairs of colistin-susceptible and - resistant KPC-producing K. pneumoniae clinical strains. Methods: The strains were subjected to high-throughput sequencing with Illumina HiSeq. The mgrB gene was amplified by PCR and sequenced. Lipid profiles were determined using MALDI-TOF MS. Results: All patients were treated with colistimethate prior to the isolation of colistin-resistant strains (MIC > 2 mg/L). Seven of 11 colistin-resistant strains had deletion or insertional inactivation of mgrB. Three strains, including one with an mgrB deletion, had non-synonymous pmrB mutations associated with colistin resistance. When analysed by MALDI-TOF MS, all colistin-resistant strains generated mass spectra containing ions at m/z 1955 and 1971, consistent with addition of 4-amino-4-deoxy-L-arabinose (Ar alpha 4N) to lipid A, whereas only one of the susceptible strains displayed this lipid A phenotype. Conclusions: The pathway to colistin resistance in K. pneumoniae primarily involves lipid A modification with Ar alpha 4N in clinical settings.
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