Biodegradation of erythromycin by Delftia lacustris RJJ-61 and characterization of its erythromycin esterase

The residual erythromycin in fermentation waste can pollute the environment and threaten human health. However, there are no effective approaches to remedy this issue. In this study, an erythromycin-degrading bacterium named RJJ-61 was isolated and identified as a strain of Delftia lacustris based on morphological and phylogenetic analyses. The degradation ability of this strain was also evaluated; it could degrade 45.18% of erythromycin at 35°C in 120 h. Furthermore, the key degradation gene ereA was cloned from strain RJJ-61 and expressed in Escherichia coli BL21; the molecular weight of the expressed protein was ~45 kDa. The enzyme activity of EreA was 108.0 mU ml⁻¹ at 35°C and pH 7.0. Finally, the EreA protein was used to degrade erythromycin from mycelial dregs and 50% diluted solution, and the removal rates in them were 41.42% and 69.78%, respectively. In summary, D. lacustris RJJ-61 is a novel erythromycin-degrading strain that has great potential to remove erythromycin pollutants from the environment.     

新疆伊犁地区肝硬化并消化道出血病因探讨

目的:探讨肝硬化并消化道出血病因及预防.方法:分析近5年收治202例确诊肝硬化并消化道出血患者.结果:食道、胃底静脉曲张破裂出血114例(56.44%)占首位.其他原因出血88例占43.56%.结论:肝硬化者除食道胃底静脉曲张破裂引起的消化道出血外,非食道胃底静脉曲张破裂引起的消化道出血应引起重视,急诊胃镜检查是找到消化道出血病因的首要方法.     

2016至2017年全国血流感染细菌耐药监测(BRICS)报告

目的通过研究血液感染的病原菌分布及对其耐药性监测,准确掌握我国细菌耐药状况。方法收集全国血流感染细菌耐药监测联盟(BRICS)成员单位2016年1月至2017年12月所有按操作规程分离自血培养的感染病原菌,按美国临床和实验室标准化研究所(CLSI)推荐的琼脂稀释法或肉汤稀释法进行抗菌药物药敏性测定。采用WHONET 5.6进行统计分析。结果2016年1月至2017年12月共收集33家成员单位8154株病原菌,其中革兰阳性菌为2325株(28.5%),革兰阴性菌5829株(71.5%)。最常见的前10位病原菌为大肠埃希菌2831株(34.7%)、肺炎克雷伯菌1289株(15.8%)、金黄色葡萄球菌922株(11.3%)、凝固酶阴性葡萄球菌605株(7.4%)、鲍曼不动杆菌372株(4.6%)、铜绿假单胞菌315株(3.9%)、屎肠球菌312株(3.8%)、链球菌属237株(2.9%)、阴沟肠杆菌220株(2.7%)和粪肠球菌205株(2.5%)。耐甲氧西林金黄色葡萄球菌(MRSA)和耐甲氧西林凝固酶阴性葡萄球菌(MRCNS)检出率分别为34.2%(315/922)和77.7%(470/605),未检测到对万古霉素耐药的葡萄球菌。屎肠球菌对万古霉素的耐药率为0.6%(2/312),未检测到耐万古霉素的粪肠球菌。产超广谱β-内酰胺酶(ESBLs)大肠埃希菌、肺炎克雷伯菌、变形杆菌属分别为55.7%(1576/2831)、29.9%(386/1289)、38.5%(15/39);耐碳青霉烯类大肠埃希菌、肺炎克雷伯菌分别为1.2%(33/2831)、17.5%(226/1289)。鲍曼不动杆菌对多黏菌素B和替加环素的耐药率分别为14.8%(55/372)和5.9%(22/372);铜绿假单胞菌对多黏菌素B和碳青霉烯类的耐药率分别为1.3%(4/315)和18.7%(59/315)。结论我国血流感染病原菌以革兰阴性菌为主,大肠埃希菌为最常见的病原菌;MRSA的检出率较国内同期其他监测低;耐碳青霉烯大肠埃希菌处于较低水平,耐碳青霉烯肺炎克雷伯菌呈上升趋势。