Killing of VRE Enterococcus faecalis by commensal strains: Evidence for evolution and accumulation of mobile elements in the absence of competition

Enterococci are members of the gastrointestinal tract of humans and most animals that, over the past 3 decades, have emerged as leading causes of multidrug resistant hospital acquired infection (HAI). In addition to their general hardiness, many traits have entered enterococcal lineages through horizontal gene transfer, which has led to the evolution of pathogenic hospital-associated lineages uniquely adapted for survival and proliferation in the antibiotic perturbed ecology of the gastrointestinal tract. We recently observed that the accretion of mobile genetic elements in the prototype vancomycin resistant E. faecalis, clinical isolate V583, renders it unable to co-exist with native enterococci in healthy human fecal flora. In this addendum, we discuss how these findings inform our understanding of how multidrug resistant enterococci evolve, and the implications for the development of treatments that limit colonization and spread of highly antibiotic refractory microbes of this type.     

Radium-223 and metastatic castration-resistant prostate cancer: All that glitters is not gold

After being approved by the National Drug Agency in several countries, Radium-223 (Ra-223) is gaining wide acceptance in the treatment of bone metastatic castration resistant prostate cancer. The exact mechanism of action remain unclear: The established model of direct alpha-particle irradiation from the remodelling bone surface, where Ra-223 accumulates, surrounding the tumor foci can explain a lethal effect only on metastatic microdeposits, but not on higher tumor burden. According to the “pre-metastatic niche model”, it is likely that Ra-223 targets several non-tumoral cell types of the tumor microenvironment involved in the complex mechanism of cancer bone homing and colonization. A deeper insight into this hypothetical mechanism will lead to a more accurate dosimetric approach and to find optimal sequencing and/or combination with the other therapeutic options.     

多耐药大肠埃希菌NB8株全基因组耐药基因检测

目的检测1株多耐药大肠埃希菌NB8株的遗传学背景。方法病原分离自2012年4月宁波市第一医院住院患者尿液,作16S rDNA和gyrA基因测序、BLASTn比对确认为大肠埃希菌,采用Illumina HiSeq与Ion Torrent PGM两种大规模并行测序仪进行全基因组分析,再行人工测序。最后NB8株和9株已完成全基因组测序的大肠埃希菌耐药基因的比较基因组学研究。结果多耐药大肠埃希菌NB8株全基因组测序得到一条推定的染色体序列,长4 550 369 bp (内含14个缺口),得到一条推定的质粒序列,长635 377 bp(内含33个缺口)。从NB8株全基因组数据中挖掘出了β-内酰胺类、氨基糖苷类、喹诺酮类、大环内酯类、磺胺类、四环素类、多粘菌素的耐药基因,并挖掘出接合性质粒、转座子、插入序列、整合子的遗传标记,以及5大类外排泵基因。结论多耐药大肠埃希菌NB8株遗传学背景明确,主动外排机制增强也会导致或者增强NB8株的耐药性。质粒、转座子和整合子等可移动遗传元件可以使细菌的耐药性得以快速传播,使受体菌表现为多重耐药。     

内蒙古布鲁氏菌临床分离株多位点序列分型研究

目的探讨临床分离布鲁氏菌的种群结构和遗传进化特征。方法布鲁氏菌标准参考菌株羊种16M,牛种544A和猪种1 330 S作为对照菌株,采用多位点序列分型(Multiple locus sequence typing,MLST)方法对内蒙古地区分离的116株羊种布鲁氏菌进行分析,确定待测菌株的序列型(STs),用软件BioNumerics(Version 5.0)构建菌株的最小生成树。结果116株羊种布鲁氏菌全部为ST8型,9个MLST位点的变异完全相同,分离株种群结构单一;羊种菌的生物型与ST型无明显关联,ST8型菌系该地区的主要流行菌种,并与内蒙古地区先前分离羊种布鲁氏菌进化程度相同,且有密切的亲缘关系。结论羊种布鲁氏菌的序列分型(ST)与常规生物分型存在差异,ST8型菌可能具有较强的环境适应性和致病性。MLST是一种较好的羊布鲁氏菌种群和进化关系研究方法,但更适合于具有较大时间跨度和地理分布菌株间的流行病学调查。     

Galectin-3 and prediction of therapeutic response to renal sympathetic denervation

The profibrotic mediator Galectin-3 (Gal-3) has been associated with aldosterone-mediated vascular inflammation, fibrosis, and stiffness. We evaluated whether the Gal-3 levels and change in Gal-3 as associated with renal denervation can serve as prediction of therapeutic response to renal denervation. A total of 42 patients with resistant hypertension undergoing renal sympathetic denervation (RDN) were included. Blood pressure was evaluated by 24-h ambulatory measurement before RDN and 1, 3 and 6 months after RDN. Treatment response was defined as a drop in systolic ambulatory blood pressure of >5 mm Hg after 6 months. Blood samples were assessed for Gal-3 levels. For the entire group, a significant drop in mean systolic ambulatory blood pressure of 5.2 ± 18.6 mm Hg was observed (p = 0.032). The responder rate was 50% (n = 21). At baseline, Gal-3 levels were significantly higher in responders (14.5 ± 6.0 vs. 10.95 ± 4.6 ng/ml, p = 0.017). There were no significant changes of Gal-3 levels during the follow-up period. The profibrotic biomarker may help to identify patients suitable for RDN.     

螺内酯治疗难治性高血压的研究进展

难治性高血压一直是高血压治疗的难点,通常使用多种药物治疗仍不能达标,能引起心、脑、肾等严重靶器官损害。近年来研究发现,在原治疗基础上加用螺内酯能有效促进难治性高血压的达标,故本文就螺内酯的作用机制和临床应用进行综述。     

2014年长沙市155株耐多药结核分枝杆菌耐药结果分析

目的 分析长沙耐多药结核分枝杆菌(MDR-TB)菌株对抗结核药物的敏感性,为防治耐多药结核病提供科学依据。 方法 采用绝对浓度间接法检测2014年长沙市155株耐多药结核分枝杆菌临床分离株对一二线抗结核药物的耐药性,回顾性分析其耐药情况。 结果 155例耐多药结核分枝杆菌分离株对一二线抗结核药物耐药率从高到低为:链霉素(S)＞乙胺丁醇(E)＞左氧氟沙星(OFL)＞ 对氨基水杨酸钠(PAS)＞丙硫异酰胺(TH)＞卡那霉素(K)= 吡嗪酰胺(PZA),耐药率依次为:70.32%、36.13%、20.65%、12.90%、8.39%、3.87％、3.87%。耐两种药的耐药株达46株,其中以链霉素与乙胺丁醇为主,其耐药率达29.68%;耐三种药的耐药株达18株,其中以链霉素、乙胺丁醇与左氧氟沙星为主,其耐药率达11.61%;耐四种药的耐药株有5株,其中以链霉素、乙胺丁醇、左氧氟沙星及丙硫异酰胺为主,耐药率为3.23%;耐五种药和六种药的各有1株和2株。 结论 2014年长沙市MDR-TB对一线甚至二线抗结核药耐药严重,为MDR-TB防治带来巨大挑战。     

Elizabethkingia meningoseptica: Emergent bacteria causing pneumonia in a critically ill child

Elizabethkingia meningoseptica is an unusual, highly resistant, gram‐ negative bacillus. While E. meningoseptica–associated meningitis outbreaks have been well‐documented in hospital neonatal wards and among immunocompromised adults, reports describing this microorganism in critically ill children are scarce. The purpose of this report was to describe a case of a 3 year‐old girl who developed pneumonia caused by E. meningoseptica in the setting of previous use of broad‐spectrum antibiotics and to review the pediatric literature regarding this pathogen.