An Outbreak of Infections Caused by a Klebsiella pneumoniae ST11 Clone Coproducing Klebsiella pneumoniae Carbapenemase-2 and RmtB in a Chinese Teaching Hospital / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Klebsiella pneumoniae carbapenemase (KPC)-producing K. pneumoniae bacteria, which cause serious disease outbreaks worldwide, was rarely detected in Xiangya Hospital, prior to an outbreak that occurred from August 4, 2014, to March 17, 2015. The aim of this study was to analyze the epidemiology and molecular characteristics of the K. pneumoniae strains isolated during the outbreak.</p><p><b>METHODS</b>Nonduplicate carbapenem-resistant K. pneumoniae isolates were screened for blaKPC-2and multiple other resistance determinants using polymerase chain reaction. Subsequent studies included pulsed-field gel electrophoresis (PFGE), multilocus sequence typing, analysis of plasmids, and genetic organization of blaKPC-2locus.</p><p><b>RESULTS</b>Seventeen blaKPC-2-positive K. pneumoniae were identified. A wide range of resistant determinants was detected. Most isolates (88.2%) coharbored blaKPC-2and rmtB in addition to other resistance genes, including blaSHV-1, blaTEM-1, and aac(3)-IIa. The blaKPC-2and rmtB genes were located on the conjugative IncFIB-type plasmid. Genetic organization of blaKPC-2locusin most strains was consistent with that of the plasmid pKP048. Four types (A1, A2, A3, and B) were detected by PFGE, and Type A1, an ST11, was the predominant PFGE type. A novel K. pneumoniae sequence type (ST1883) related to ST11 was discovered.</p><p><b>CONCLUSIONS</b>These isolates in our study appeared to be clonal and ST11 K. pneumoniae was the predominant clone attributed to the outbreak. Coharbing of blaKPC-2and rmtB, which were located on a transferable plasmid, in clinical K. pneumoniae isolates may lead to the emergence of a new pattern of drug resistance.</p>

NDM-1-producing Klebsiella pneumoniae in mainland China / 中国当代儿科杂志

<p><b>OBJECTIVE</b>To investigate the characteristics of New Delhi metallo-beta-lactamase-1 (NDM-1) gene of Klebsiella pneumoniae (K. pneumoniae) emerging in Hunan, and its relationship to antibiotic resistance.</p><p><b>METHODS</b>The clinical strain was isolated from a sputum sample of a child with severe pnemonia and toxic myocarditis who was admitted into a general hospital of Hunan Province. VITEK-2 compact instrument was used for bacterial identification and antibiotic susceptibility test. Modified Hodge test was used for the screening of carbapenemase. EDTA-synergy test and combination disk diffusion test were used for detection of metallo-β-lactamase (MBL). PCR was performed for amplification of NDM-1 genes and the positive products were sequenced and analyzed with BLAST. Conjugation was also performed to analyze mechanisms of antibiotic resistance. The results of antibiotic susceptibility tests were compared before and after conjugation.</p><p><b>RESULTS</b>The isolated strain was identified as K.pneumoniae. Modified Hodge test, EDTA-synergy test and combination disk diffusion test were all positive for the strain. The homology between gene sequence of PCR amplification products and NDM-1 gene FN396876.1 in the GenBank was 100%. Transconjugant DNA was used as template for the amplification of NDM-1 gene. The amplification products were sequenced and found to be the same as the NDM-1 gene amplification product of the donor strain. The MIC of transconjugant E.coli J53 (NDM-1) to all the β-lactams increased significantly compared with the recipient strain E.coli J53. The MIC of ertapenem and imipenem increased by more than 8 times, while the MIC of ceftazidime and ceftriaxone increased by more than 64 times.</p><p><b>CONCLUSIONS</b>This study first identified a strain of K. pneumoniae carrying NDM-1 in mainland China. NDM-1 gene can be transmitted among different strains and causes extensively drug-resistance to β-lactams.</p>