Natural antimicrobial susceptibility patterns and biochemical profiles of Leclercia adecarboxylata strains

Leclercia adecarboxylata is an opportunistic human pathogen that phenotypically resembles Escherichia coli. The natural susceptibilities of 101 Leclercia strains to 70 antimicrobial agents were investigated. MICs were determined with a microdilution procedure in cation-adjusted Mueller-Hinton broth (all strains) and IsoSensitest broth (some strains). Natural susceptibility patterns were assessed using German (DIN) standards (when applicable). In addition, biochemical properties recommended for the phenotypic identification of L. adecarboxylata were evaluated, applying two commercially available identification systems for Enterobacteriaceae and seven conventional tests. L. adecarboxylata strains were naturally sensitive to tetracyclines, aminoglycosides, all but two beta-lactams, quinolones, folate pathway inhibitors, chloramphenicol, nitrofurantoin and azithromycin. They were naturally resistant to penicillin G, oxacillin, erythromycin, roxithromycin, clarithromycin, ketolides, lincosamides, streptogramins, linezolid, glycopeptides, rifampicin, fusidic acid and fosfomycin. There were only minor medium-dependent differences in susceptibility to most antibiotics. Lysine decarboxylase, malonate assimilation and acid production from arabitol and cellobiose, but not from adonitol and sorbitol, allowed definitive separation of L. adecarboxylata from E. coli. The results of this study form a database that can be applied to validate forthcoming antibiotic susceptibility tests of L. adecarboxylata, and might contribute to its reliable identification. Susceptibility patterns did not indicate obvious therapeutic difficulties for treatment of Leclercia infections. Special attention should be paid to biochemically aberrant leclerciae. Apart from biochemical features, fosfomycin susceptibility might be useful to differentiate between L. adecarboxylata and E. coli.     

一起由非脱羧勒克菌引起食物中毒的调查和实验室检验与分析

目的对一起食物中毒的采集样本进行相关微生物学检验,确定引起食物中毒的病原菌,并进行16S rRNA序列分析确定其归属。方法根据流行病学调查及临床表现,选择疑似的病原菌,根据GB/T4789-2003、GB/T4789-2008、GB/T4789-2010、WS/T9-1996、《卫生防疫细菌检验》对采集的样品进行病原菌分离与鉴定,对菌株的16S rRNA基因测序结果进行分析。结果从1份疑似中毒食物鱼香茄子中检出非脱羧勒克菌,该菌株属于阿氏肠杆菌。结论综合流行病学调查、临床资料和实验室检测结果,提示该次食物中毒由非脱羧勒克菌污染食物所致。     

关于烟台地区首次从鱼香茄子中检出1株非脱羧勒克菌的研究

目的对采集的179份烟台市某企业餐厅的食物样本进行食源性致病菌检验,确定食物中微生物污染状况。方法根据流行病学调查及采集的食品类型,选择疑似的病原菌,根据GB/T4789-2003、GB/T4789-2008、GB/T4789-2010、WS/T9-1996、《卫生防疫细菌检验》对采集的样品进行病原菌分离与鉴定。结果从鱼香茄子中检出1株疑似福氏志贺氏菌,该菌染色镜检、生化试验、自动生化鉴定和附加试验结果与非脱羧勒克菌一致。结论从鱼香茄子中分离出的菌株为非脱羧勒克菌。     

药品中非脱羧莱克勒菌的分离与鉴定

目的对一批氨肽素片中的疑似控制菌进行分离、鉴定。方法经营养琼脂培养基分离、纯化得到纯菌落SC-01,经基本定向生化试验分析后,用全自动微生物鉴定系统VITEK 2 Compact对该菌快速鉴定。结果菌SC-01革兰氏染色为G-,3%KOH试验"+",接触酶试验"+",O/F试验为发酵型,菌种鉴定结果为非脱羧莱克勒菌,相似性概率为99%。结论可以应用VITEK 2 Compact对细菌SC-01进行分离、鉴定。     

Late-onset Leclercia adecarboxylata bacteraemia in a premature infant in the NICU

Late-onset sepsis is a unique entity in the neonatal intensive care unit (NICU), as organisms involved are, by definition, nosocomial. As such, a limited number of microbes are characteristically involved. Leclercia adecarboxylata is a gram-negative bacillus rarely cultured in a clinical context, with the few published cases primarily involving immunocompromised adults. We present an ex-26-week newborn girl who developed late-onset sepsis with Leclercia adecarboxylata bacteraemia in the NICU. The infection was successfully treated with gentamicin and cefotaxime. This is the fifth paediatric report of Leclercia adecarboxylata infection, and the first in a neonate. The case raises the possibility that prior courses of antibiotics may have predisposed this individual to a rare infection essentially limited to immunocompromised individuals. CONCLUSION: Leclercia adecarboxylata is a rare infection, particularly in immunocompetent individuals. In neonates, the clinical course can be good with timely initiation of appropriate antibiotics.     

Leclercia adecarboxylata peritonitis in a child receiving chronic peritoneal dialysis

A 5 year old boy with end-stage renal disease presented with clinical and laboratory findings of peritonitis. Peritoneal fluid revealed infection with Leclercia adecarboxylata. This is a motile, gram-negative bacillus, formerly designated enteric group 41 and Escherichia adecarboxylata. To our knowledge, this is the first reported case of peritonitis due to this organism. Received: 21 February 2000 / Revised: 22 May 2000 / Accepted: 24 May 2000     

发现1株产NDM-1型碳青霉烯酶非脱羧勒克菌

目的探讨1株碳青霉烯类耐药非脱羧勒克菌的耐药机制。方法采用全自动微生物分析仪、基质辅助激光解吸电离飞行时间质谱(MALDI-TOF MS)技术及16S r RNA序列分析进行菌种鉴定;采用全自动微生物分析仪进行常规药物敏感性试验,用E-test条检测菌株对亚胺培南的最低抑菌浓度(MIC);改良碳青霉烯酶灭活试验(m CIM法)检测碳青霉烯酶表型;聚合酶链反应(PCR)及测序确定耐药基因型;采用接合试验、S1酶切脉冲场凝胶电泳(S1-PFGE)方法分析其携带质粒的特征。结果临床分离非脱羧勒克菌菌株对亚胺培南、除氨曲南外的其他β内酰胺类抗菌药物及氨基糖苷类耐药,对喹诺酮类和磺胺类药物敏感;接合试验使受体菌E.coli J53获得与非脱羧勒克菌相似的耐药谱。碳青霉烯酶表型试验阳性,PCR扩增及测序表明该菌株同时携带blaNDM-1、blaTEM和aac(6')-Ib,而接合子仅携带blaNDM-1;S1-PFGE示非脱羧勒克菌具有3个质粒。结论非脱羧勒克菌对碳青霉烯类药物耐药为携带blaNDM-1基因造成,该基因可能存在于100 kb左右的可接合传递的质粒上。     

腹泻患者粪便中非脱羧莱克勒菌的分离和鉴定

非脱羧莱克勒菌(Leclercia adecarboxylata)可见于由多病原引起的伤口感染[1];而该菌单独感染则见于血液感染标本以及免疫低下患者[2].目前,粪便标本中有关非脱羧莱克勒菌的研究报道较少.本研究于2010年10月自2例腹泻患者粪便中分离到非脱羧莱克勒菌,现就其特性进行分析鉴定.