目的 检测并鉴定洛菲不动杆菌多药耐药菌株中新德里金属β内酰胺酶新德里金属β-内酰胺酶（new delhi metallo-β-lactamase, NDM）-1基因表达。方法 抗菌药物最小抑菌浓度（minimal inhibitory, MIC）筛选多药耐药菌株，PCR方法鉴定候选菌株中金属β-内酰胺酶基因，经PCR测序、亚胺培南和亚胺培南+ EDTA复合纸片的双纸片协同法鉴定金属β内酰胺酶表型，并采取接合实验和全基因组测序来确定NDM-1。结果 自458株金属β-内酰胺酶阳性菌株中分离出一株洛菲不动杆菌，并检出NDM-1基因，此菌株并不合并存在VIM和IMP金属β-内酰胺酶基因阳性表达。该菌株对所有的β-内酰胺类抗生素均不敏感，而对阿米卡星、多粘菌素、替加环素敏感。全基因组测序确定其位于一个48.9 kb的质粒上，目标带纯化后克隆、扩增的目标序列与文献报道的NDM-1基因同源性为100%。结论 NDM-1是一种针对碳青霉烯类抗生素耐药的新机制，临床工作者应关注其对洛菲不动杆菌多药耐药的影响。
Abstract
Objective To detect and identify multidrug resistance gene of new delhi metallo-beta-lactamase (NDM) 1 in a Acinetobacter lwoffii isolate. Methods Tigecycline MICs were used to screen the multidrug isolate while PCR were used to detect the expression of metallo-β-lactamases among the isolates. Species identification and phenotype analysis were carried out by PCR sequencing, Imipenem and EDTA double disc synergy test, respectively. Genetic location of NDM-1 was determined by Conjugation experiments and whole genome sequencing. Results One strain of A. lwoffii with positive expression of NDM-1 was isolated from 458 carbapenem-non-susceptible cases, which without VIM and IMP genes positive expression concomitantly. This strain with expression of NDM-1 gene resist to all β-lactam antibiotics while retaining the susceptibility to amikacin, colistin and tigecycline. Sequencing showed 100% identities with previously reported genes, and whole genome sequencing conformed NDM-1 gene located on a 48. 9 kb plasmid. Conclusions NDM-1, as a na ve mechanism, involved in resistance to carbopenems. The clinical physicians should pay more attention on impact of multidrug resistance of Acinetobacter lwoffii due to the expression of NDM-1.
关键词
新德里金属β-内酰胺酶 /
洛菲不动杆菌 /
多药耐药基因
Key words
new delhi metallo-β-lactamase /
acinetobacter lwoffii /
multidrug resistance gene
{{custom_sec.title}}
{{custom_sec.title}}
{{custom_sec.content}}
参考文献
［1］ Yong D, Toleman M A, Giske C G, et al. Characterization of a new metallo-b-lactamase gene, blaNDM-1, and a novel erythromycin esterase gene carried on a unique genetic structure in Klebsiella pneumoniae sequence type 14 from India［J］. Antimicrobial Agents Chemother, 2009, 53(12): 5046–5054.
［2］ Kumarasamy K K, Toleman M A, Walsh T R, et al. Emergence of a new antibiotic resistance mechanism in India, Pakistan, and the UK: a molecular, biological, and epidemiological study［J］. Lancet Infect Dis, 2010, 8(10): 597–602.
［3］ Queenan A M, Bush K. Carbapenemases: the versatile beta-lactamases［J］. Clin Microbiol Rev, 2007, 20(3): 440–458.
［4］ Robert A. Bonomo. New Delhi Metallo-β-Lactamase and Multidrug Resistance: A Global SOS［J］? Clinical Infectious Diseases, 2011, 52(4): 485–487
［5］ Kumarasamy K, Thirunarayan K, Padma K. Coexistence of blaOXA-23 with blaNDM-1 and armA in clinical isolates of Acinetobacter baumannii from India［J］. J Antimicrob Chemother, 2011, 65(10):2253-2254
［6］ Poirel L, Maskari Z,Nordmann P, et al. NDM-1-producing Klebsiella pneumoniae isolated in the Sultanate of Oman［J］. J Antimicrobial Chemotherapy, 2011, 66(2): 304-306.
［7］ Poirel L, Lagrutta E, Nordmann P, et al. Emergence of Metallo-β-Lactamase NDM-1-Producing Multidrug-Resistant Escherichia coli in Australia［J］. Antimicrobial Agents and Chemotherapy, 2010, 54(11): 4914-4916.
［8］ Huo T I. The first case of multidrug-resistant NDM-1-harboring Enterobacteriaceae in Taiwan: here comes the superbacteria［J］. J Chin Med Assoc, 2010, 73(11): 557-558.
［9］ Ho P L, Lo W U, Yeung M K, et al. Complete sequencing of pNDM-HK encoding NDM-1 carbapenemase from a multidrug-resistant Escherichia coli strain isolated in Hong Kong［J］. PLoS One, 2011, 6(3): e17989.
(2012-12-11
PDF(652 KB)
