利奈唑胺对肾功能不全G~+感染患者血小板减少的相关性研究

目的:分析利奈唑胺对肾功能不全G+患者血小板减少的关系。方法:回顾性分析92例应用利奈唑胺治疗的革兰阳性球菌感染患者的临床资料,根据是否伴有肾功能不全分为肾功能不全组(33例),正常组(59例),检测用药前、用药后血小板计数,观察停药后血小板计数恢复正常时间及不良反应发生情况。结果:肾功能不全组治疗后血小板计数显著低于治疗前及正常组(P0.01),正常组治疗前、后血小板计数比较无统计学意义(P0.05);肾功能不全组血小板减少发生率高于正常组(P0.05);停药后正常组血小板恢复正常时间短于肾功能不全组(P0.01);肾功能不全组血红蛋白下降率高于正常组(P0.05),其余不良反应发生率比较差异无统计学意义(P0.05)。结论:感染患者肾功能可影响利奈唑胺所致血小板减少发生率,肾功能不全患者在应用利奈唑胺时应定期监测血小板计数。     

A new and rapid method for monitoring the new oxazolidinone antibiotic linezolid in serum and urine by high performance liquid chromatography-integrated sample preparation

A sensitive and rapid HPLC-assay for determining the new oxazolidinone antibiotic linezolid in serum and urine is described. HPLC-integrated sample preparation permits the direct injection of serum and urine samples without any pre-treatment. The in-line extraction technique is realized by switching automatically from the extraction column to the analytical column. After the matrix has passed the extraction column the retained analyte will be quantitatively transferred to the analytical column where separation by isocratic HPLC will be performed. Linezolid is detected according to its absorption maximum at 260 nm. The quantification limits are estimated to be 0.3 and 0.5 μg/ml in serum and urine samples, respectively. The described procedure allows sample clean-up and determination of the antibiotic within 20 min, thereby facilitating drug-monitoring in clinical routine.     

利奈唑胺治疗儿童社区获得性金黄色葡萄球菌肺炎的临床疗效分析

目的:分析儿童社区获得性金葡菌肺炎应用利奈唑胺的临床疗效.方法:选择2008-1-1至2009-3-1在青岛大学医学院附属医院普通儿科及青岛市儿童医院诊断社区获得性金葡菌肺炎患儿22人为研究对象,分析其体温、咳嗽、肺部罗音、住院时间等临床资料.结果:患儿的平均住院时间为13.0±2.26天,有效率100%,不良反应发生率4.55%.结论:利奈唑胺治疗儿童社区获得性金葡菌肺炎有较高的临床治愈率,可快速改善症状.缩短住院时间.     

An azido-oxazolidinone antibiotic for live bacterial cell imaging and generation of antibiotic variants

An azide-functionalised analogue of the oxazolidinone antibiotic linezolid was synthesised and shown to retain antimicrobial activity. Using facile ‘click’ chemistry, this versatile intermediate can be further functionalised to explore antimicrobial structure–activity relationships or conjugated to fluorophores to generate fluorescent probes. Such probes can report bacteria and their location in a sample in real time. Modelling of the structures bound to the cognate 50S ribosome target demonstrates binding to the same site as linezolid is possible. The fluorescent probes were successfully used to image Gram-positive bacteria using confocal microscopy.     

RNA-Seq探索低水平利奈唑胺耐药粪肠球菌机制

为了探索低水平利奈唑胺耐药粪肠球菌机制,本研究采用Illumina HiSeq 4000高通量转录组测序技术对低水平利奈唑胺耐药粪肠球菌(P10748 MIC:8 mg/L)和利奈唑胺敏感粪肠球菌(3138 MIC:2 mg/L)进行测序及生物信息学分析,以标准菌株ATCC29212作为质量评估参考。利用GO和KEGG数据库对差异表达基因进行注释与富集分析,并利用荧光定量PCR对测序中的差异表达基因进行验证。结果显示,测序共获得了3.57 Gb有效数据,通过De novo拼接获得1 920条unigenes,总长度为2 122 210 bp,平均长度为1 105 bp。差异基因模式聚类分析显示共有150个显著性差异表达基因(FDR≤0.001,|log2 Ratio|≥1),其中141个上调,9个下调。其中生物膜形成和外排泵相关基因esp、optrA、fexA在耐药菌中显著上调。GO功能注释结果显示,催化活性、代谢过程和细胞是注释最多的条目;Pathway富集分析发现,肽聚糖生物合成、缬氨酸亮氨酸和异亮氨酸的降解和硫代谢为显著性富集通路(p<0.05)。荧光定量PCR结果与测序结果基本一致。推测膜转运蛋白和生物膜形成可能在耐药机制中具有重要作用,为低水平利奈唑胺耐药肠球菌机制提供了可参考的耐药靶标。     

Efficacy and Safety of Linezolid in Treating Gram-Positive Bacterial Infection in the Elderly: A Retrospective Study

Linezolid is commonly used for the treatment of drug-resistant Gram-positive bacterial infection. This study aimed to evaluate the efficacy and safety of linezolid in treating Gram-positive bacterial infection in the elderly from January 2010 to December 2012. Total 40 elderly patients (>60 years old) with Gram-positive bacterial infection were treated with linezolid and their demographic and clinical data were collected and analyzed. Among the 40 patients, 31 patients (77.5 %) were cured. Linezolid caused little adverse effects on liver and renal function. The main adverse effect was thrombocytopenia and its incidence was significantly associated with baseline platelet count and the duration of treatment (P < 0.05). Logistic regression analysis showed that the baseline platelet count <200 × 10⁶/mL, but not the age, the sex, the length of hospital stay, baseline levels of hemoglobin, alanine aminotransferase, or creatinine clearance rate was significantly associated with linezolid-induced thrombocytopenia. In conclusion, linezolid is effective to cure Gram-positive bacterial infection in the elderly and causes little adverse effects on liver and renal function. Timely monitoring of baseline platelet count may be helpful to guide the use of linezolid to avoid the occurrence of thrombocytopenia.     

Synthesis of conjugates between oxazolidinone antibiotics and a pyochelin analogue

Pseudomonas aeruginosa is a Gram-negative pathogenic bacterium responsible for severe infections, and it is naturally resistant to many clinically approved antibiotic families. Oxazolidinone antibiotics are active against many Gram-positive bacteria, but are inactive against P. aeruginosa. Increasing the uptake of oxazolidinones through the bacterial envelope could lead to an increased antibiotic effect. Pyochelin is a siderophore of P. aeruginosa which delivers external iron to the bacterial cytoplasm and is a potential vector for the development of Trojan Horse oxazolidinone conjugates. Novel pyochelin-oxazolidinone conjugates were synthesized using an unexpectedly regioselective peptide coupling between an amine functionalized pyochelin and oxazolidinones functionalized with a terminal carboxylate.     

Rapid-onset, linezolid-induced lactic acidosis in MELAS

Due to their prokaryotic origins, mitochondria are susceptible to a number of antibiotics that target the bacterial ribosome, and this vulnerability is exacerbated by certain mutations of the mitochondrial genome.MELAS (mitochondrial encephalomyopathy, lactic acidosis and stroke-like episodes) syndrome is characterised by biochemical and structural abnormalities of the muscle mitochondria, in which episodes of lactic acidosis stem from dysfunction of assembled respiratory complex I.Linezolid is an oxazolidinone antibiotic that has been reported to induce lactic acidosis, especially after prolonged administration, through inhibition of the mitochondrially synthesised components of oxidative phosphorylation.We report a patient with longstanding MELAS who suffered a severe lactic acidosis of rapid onset, with associated features of mitochondrial failure, shortly after the commencement of linezolid therapy and in the context of an otherwise improving clinical picture.This case emphasises the importance of circumspection when utilising drugs known to be toxic to the mitochondrion in patients with mitochondrial disease. In particular, given the biochemically plausible interaction, it would seem prudent to avoid the use of linezolid in patients with MELAS whenever possible.     

利奈唑胺治疗重症肺炎的疗效评价及对患者血清IL-1β，TGF-β和TNF-α水平的影响

目的:分析利奈唑胺治疗重症肺炎患者的疗效及对血清炎症因子水平的影响。方法:收集2014年5月~2016年5月于我院就诊的104例重症肺炎患者,依据抽签法分作对照组(n=52)及观察组(n=52),对照组采用万古霉素治疗,观察组采用利奈唑胺治疗,观察组两组血清炎症因子(白细胞介素-1β(IL-1β)、转化生长因子-β(TGF-β)、肿瘤坏死因子-α(TNF-α))、血气分析指标(血氧饱和度(SaO_2)、氧分压(PaO_2)、氧合指数(PaO_2/FiO_2))、肺表面活性蛋白A(SP-A)、表面活性蛋白B(SP-B)、表面活性蛋白C(SP-C)、表面活性蛋白D(SP-D)、肺功能(最大呼气中段流量(MMF)、峰流速(PEF)、最大吸气压(Pimax)、最大呼气压(PEmax))疗效及安全性。结果:治疗后,观察组血清IL-1β、TNF-α、SP-A、SP-B、SP-C、SP-D均显著低于对照组,且观察组TGF-β、SaO_2、PaO_2、PaO_2/FiO_2、MMF、PEF、Pimax、PEmax明显高于对照组,差异有统计学意义(P0.05)。观察组总有效率高于对照组(P0.05),两组不良反应无统计学意义(P0.05)。结论:利奈唑胺治疗重症肺炎患者的疗效确切,能够调节血清炎症因子的水平,恢复抗炎与促炎因子的动态平衡。     

Development of a liquid chromatography method for the determination of linezolid and its application to in vitro and human microdialysis samples

Linezolid is a new, promising antibacterial agent to treat severe infections. A rapid HPLC assay using UV detection for the determination in microdialysate and human plasma was developed. After sample preparation, using acetonitrile for plasma and water for microdialysate, 20 microl was injected and separated on a RP-18 column. Overall, the assay exhibited good precision and accuracy. The diffusion properties of linezolid investigated in in vitro microdialysis experiments revealed a mean relative recovery of 77.5% (CV: 5.4%; delivery and recovery experiments). Following characterization of linezolid in in vitro microdialysis, the setting is suitable for application in clinical studies.