奇异变形杆菌中基因岛介导的多重耐药传播研究进展

奇异变形杆菌是导致医院内感染的重要条件致病菌,广泛分布于自然环境及人和动物的肠道中。基因岛是细菌染色体上约10-200 kb独立的DNA片段,能促进宿主细菌适应复杂多变的环境,与细菌适应性进化密切相关。近年来在奇异变形杆菌基因组中发现了多个与多重耐药密切相关的基因岛,包括沙门菌基因岛1及其相关基因岛、SXT/R391整合性接合元件、PmGRI1等,表明基因岛在奇异变形杆菌多重耐药形成和传播中具有重要作用。本文对奇异变形杆菌中与耐药相关基因岛的结构特征、传播机制、流行情况等进行综述,以期为奇异变形杆菌中多重耐药相关基因岛的深入研究提供参考。     

利用CRISPR-Cas系统防控细菌耐药性的研究进展

细菌多重耐药是医药健康、农林牧渔、生态环境等多领域共同面临的全球性挑战.抗生素耐药基因跨物种跨区域传播是导致细菌多重耐药形成的重要原因.然而,目前尚无有效方案解决日益严峻的细菌多重耐药问题.由规律成簇间隔短回文重复序列和与之相关的蛋白组成的CRISPR-Cas系统,可靶向切割进入细菌的外源核酸,具有防控耐药基因转移导致...     

细菌中整合性接合元件的研究进展

整合性接合元件是近年来在细菌中发现的一种可移动的基因元件,它位于染色体上,可通过接合转移的方式介导细菌间基因的水平转移。这种基因的水平转移有助于细菌适应特定的环境条件,但许多整合性接合元件包含耐药基因,这些遗传元件的水平转移极大地加速了耐药基因在同种及不同种属之间的传播,造成细菌的耐药以至多重耐药问题日益严重,耐药机制日趋复杂;同时整合性接合元件与基因岛有着密切的联系,因此对其特征及转移机制进行研究很有必要。     

致病菌基因组岛的研究进展

细菌基因组岛是细菌基因组上的特定区域,和水平基因转移相关,具有一定的结构特点,常携带致病、耐药及与适应性等功能相关的基因。通过基因组岛在细菌间的移动,可以造成相关基因在细菌间的传播,在细菌生存和致病等过程中具有重要作用。目前已经可通过生物信息和分子生物学实验等方法对基因组岛进行预测和验证。通过对致病菌基因组岛的研究,可以阐释细菌致病性和耐药等重要功能的获得,对疾病进行溯源,在传染病预防控制中具有重要意义。     

IncFII-FIA-FIB型多重耐药质粒pBTR-CTXM的结构基因组学分析

【背景】IncFII-FIA-FIB型质粒广泛存在于肠杆菌科细菌中,介导了许多耐药基因的水平转移,并导致细菌多重耐药问题日益严重。【目的】分析IncFII-FIA-FIB型多重耐药质粒pBTR-CTXM的基因组结构,并研究其介导大肠杆菌BTR株的耐药基因水平转移机制。【方法】利用PCR进行耐药基因筛查;接合转移和电转化实验验证质粒pBTR-CTXM是否具备自主接合转移的特性;VITEK 2 Compact全自动细菌鉴定及药敏分析仪测定相关菌株对抗生素的药物敏感性;构建MatePair文库并进行细菌全基因组高通量测序和质粒结构基因组学分析。【结果】菌株BTR是携带blaNDM-1、blaCTX-M-15、blaTEM、qnrD、qnrS1、mph(A)、erm(B)和tetA(B)等耐药基因的多重耐药大肠杆菌,其中blaCTX-M-15、mph(A)、erm(B)和tet A(B)等耐药基因均位于大小为144 939 bp的质粒p BTR-CTXM (GenBank登录号MF156697)上,该质粒可与菌株BTR内质粒pNDM-BTR接合共转移到受体菌大肠杆菌EC600中。pBTR-CTXM具备IncFII-FIA-FIB型质粒典型的骨架区结构,其多重耐药(Multidrug-resistant,MDR)区由新的复合型转座子Tn6492、Tn2残余、Tn10残余、ISEcp1-blaCTX-M-15-Δorf477转座单元和一些插入序列组成。【结论】pBTR-CTXM中新复合型转座子Tn6492与Tn10残余和ISEcp1-blaCTX-M-15-Δorf477转座单元共同介导大肠杆菌BTR株的多重耐药与耐药基因的水平传播。     

产超广谱β-内酰胺酶细菌中I类整合子的研究进展

产超广谱β-内酰胺酶(Extended-spectrum beta-lactamase, ESBLs)细菌的多重耐药性是临床用药的一大难题, 近年研究发现其耐药性的产生与整合子密切相关, 其中临床最常见、研究最深入的是I类整合子。整合子是一种可移动基因元件, 在整合酶的作用下捕捉外源基因盒并使之表达, 是具有基因整合和切除功能的天然克隆和表达系统。研究表明I类整合子可连续捕捉和整合多种耐药基因, 以质粒或转座子为载体在细菌之间传播耐药性, 使ESBLs细菌多重耐药趋势十分严峻。本文就I类整合子的结构特征、I类整合子对耐药基因盒的整合作用及其与ESBLs细菌耐药性的关系等方面进行综述。     

福建某基层医院CRE碳青霉烯类耐药基因分析

目的 对福建省南平市第二医院分离的碳青霉烯类耐药肠杆菌科细菌进行碳青霉烯类基因和其他β-内酰胺类耐药基因检测。方法 收集碳青霉烯类耐药肠杆菌科细菌,采用Vitek-2 Compact全自动细菌鉴定/药敏仪器进行细菌鉴定和药敏试验;采用改良Hodge试验对实验菌株进行表型检测;利用PCR及测序法对常见的碳青霉烯类和β-内酰胺类耐药基因进行检测;质粒接合试验检测碳青霉烯类耐药基因是否具有可转移性。结果 共收集到4株碳青霉烯类耐药肠杆菌科细菌,呈多重耐药性。2株改良Hodge试验阳性。试验菌株均检出碳青霉烯类耐药基因（NDM-1、IMP-8或VIM-2）,并同时携带有其他β-内酰胺类基因;4株细菌中有3株的碳青霉烯类耐药基因接合成功。结论 碳青霉烯类耐药肠杆菌科细菌已在福建基层医院出现,并具有一定传播性,应引起相关主管部门的注意,以防耐药菌的流行。     

整合子与细菌耐药性

整合子是由1个编码整合酶的intI基因、2个基因重组位点、启动子和耐药基因盒组成,根据整合酶的DNA碱基序列的不同分为4类,它能通过位点的基因重组机制使耐药基因移动,传递细菌耐药性,并与多重耐药性相关。     

四年医院感染致病菌耐药性分析

目的：了解医院感染致病菌的耐药情况。方法：对我院（1000张床位）近4年医院感染致病菌药敏试验结果进行统计分析。结果：共分离出致病菌2404株,其中G^-菌974株（40.5%);G^ 菌790株（32.9%);真菌650株（26.6%)。细菌的耐药性发生了变化,氟喹喏酮类对常见细菌耐药率大于40%;第三代头孢对阴沟肠杆菌耐药率大于71%,第一代的头孢唑啉对该菌全部耐药,对其他细菌的耐药率大于60%;青霉素类中ORSA高达86.6%;细菌耐药率最低的为舒谱深,亚胺培南。结论：医院感染致病菌耐药率总体呈上升趋势,耐药谱不断变更,甚至呈现多重耐药,必须加强对细菌耐药性监测。综合分析合理选用抗生素。     

整合子基因盒系统及β-内酰胺酶介导的细菌耐药

整合子是一个能捕获并整合细胞外游离基因盒,并可使之转化为功能性基因的新型DNA元件。这种可移动的基因元件通过水平基因转移的方式极大地加速了抗性基因在同种及不同种属之间的传播,造成细菌的耐药以至多重耐药问题日益严重,耐药机制日趋复杂。尤其对临床上使用较多的头孢菌素类、青霉素类等β-内酰胺类抗生素的耐药,已给人类健康造成巨大威胁,急需阐明其复杂的耐药机制。     

食品动物养殖环境中细菌耐药性研究进展

抗生素耐药性被世界卫生组织认为是21世纪人类面临的最大的公共卫生安全问题之一。近年来,抗生素耐药基因作为一种新型污染物而受到广泛关注。养殖场现已成为耐药基因的一个重要储库,耐药菌及耐药基因随着动物排泄物进入环境,从而加速了耐药基因在环境中的传播。畜禽养殖环境中耐药基因和耐药菌可能经食物链、空气等途径传至人类,给人类健康带来巨大威胁。文中结合最新文献,主要介绍了动物养殖场抗菌药物耐药菌和耐药基因的分布特点、耐药基因的持留和传播扩散、研究方法等方面的研究进展,为食品动物养殖环境的抗菌药物耐药性风险评估提供一定支持。     

Status of pathogens,antibiotic resistance genes and antibiotic residues in wastewater treatment systems

Pathogens are becoming nearly untreatable due to the rise in gaining new resistance against standard antibiotics. Coexistence of microbial pathogens, antibiotics and antibiotic resistant genes (ARGs) in wastewater treatment plants (WWTP) provide favourable conditions for the development of new antibiotic resistant bacteria (ARB); facilitate horizontal gene transfer among pathogens and may also serve as a hotspot for the spread of ARB and genes into the environment. In this study, the current status of wastewater treatment systems in the removal of pathogens, ARGs, and antibiotic residues are discussed. WWTP are efficient in removing pathogens and antibiotic residues to a greater extend during secondary and tertiary treatment processes. Recent studies, however, have shown high variations in the presence of pathogens including ARB as well as antibiotic resistance genes (ARG) in the final effluent. Prolonged sludge retention time (SRT) and hydraulic retention time (HRT) during secondary treatment will facilitate antibiotic removal by adsorption and biodegradation. However, the above conditions can also lead to the enhancement of antibiotic resistance process in microbes. Therefore, optimum conditions for the operation of conventional WWTP for the efficient removal of antibiotics are yet to be established. The removal of antibiotic residues can be accelerated by combining conventional activated sludge (CAS) process with an additional treatment technology involving dosing with ozone. The advanced biological treatment method using membrane bioreactors (MBR) in combination with coagulation reportedly has the best ARG removal efficiency, and removes both ARB and extracellular ARGs. While studies have predicted the fate for ARGs in wastewater treatment plants, the mechanisms of ARGs acquisition remains to be conclusively established. Thus, strategies to investigate the underlying mechanism of acquisition of ARGs within the WWTP are also provided in this review.     

抗生素耐药基因在畜禽粪便-土壤系统中的分布、扩散及检测方法

抗生素耐药基因作为一种新型的环境污染物已引起研究者的高度关注。畜禽养殖业长期将抗生素添加到饲料中,在促进动物生长、预防和治疗动物疾病等方面起了重要作用。这些抗生素大多数不能被动物完全吸收,在动物肠道中诱导出耐抗生素细菌和抗生素耐药基因,并随着粪便排出体外。畜禽粪便作为重要的抗生素、耐抗生素细菌和抗生素耐药基因储存库,通过堆粪、施肥等农业活动进入土壤环境中,可刺激土壤中耐抗生素细菌和抗生素耐药基因的富集。耐药基因借助于基因水平转移等方式在土壤介质中进一步传播扩散,甚至进入植物中随食物链传播,对生态环境和人类健康造成极大的威胁。为了正确评估抗生素耐药基因的生态风险,本文结合国内外相关研究,系统阐述了畜禽粪便-土壤系统中抗生素耐药基因的来源、分布及扩散机制,同时探讨了细菌耐药性的主要研究方法,指出堆肥化处理仍是目前去除抗生素耐药基因的主要手段,并对今后的研究方向进行展望。     

Aquatic animals promote antibiotic resistance gene dissemination in water via conjugation: Role of different regions within the zebra fish intestinal tract,and impact on fish intestinal microbiota

The aqueous environment is one of many reservoirs of antibiotic resistance genes (ARGs). Fish, as important aquatic animals which possess ideal intestinal niches for bacteria to grow and multiply, may ingest antibiotic resistance bacteria from aqueous environment. The fish gut would be a suitable environment for conjugal gene transfer including those encoding antibiotic resistance. However, little is known in relation to the impact of ingested ARGs or antibiotic resistance bacteria (ARB) on gut microbiota. Here, we applied the cultivation method, qPCR, nuclear molecular genetic marker and 16S rDNA amplicon sequencing technologies to develop a plasmid‐mediated ARG transfer model of zebrafish. Furthermore, we aimed to investigate the dissemination of ARGs in microbial communities of zebrafish guts after donors carrying self‐transferring plasmids that encode ARGs were introduced in aquaria. On average, 15% of faecal bacteria obtained ARGs through RP4‐mediated conjugal transfer. The hindgut was the most important intestinal region supporting ARG dissemination, with concentrations of donor and transconjugant cells almost 25 times higher than those of other intestinal segments. Furthermore, in the hindgut where conjugal transfer occurred most actively, there was remarkable upregulation of the mRNA expression of the RP4 plasmid regulatory genes, trbBp and trfAp. Exogenous bacteria seem to alter bacterial communities by increasing Escherichia and Bacteroides species, while decreasing Aeromonas compared with control groups. We identified the composition of transconjugants and abundance of both cultivable and uncultivable bacteria (the latter accounted for 90.4%–97.2% of total transconjugants). Our study suggests that aquatic animal guts contribute to the spread of ARGs in water environments.     

Research progress on distribution,migration, transformation of antibiotics and antibiotic resistance genes (ARGs) in aquatic environment

Antimicrobial and antibiotics resistance caused by misuse or overuse of antibiotics exposure is a growing and significant threat to global public health. The spread and horizontal transfer of antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs) by the selective pressure of antibiotics in an aquatic environment is a major public health issue. To develop a better understanding of potential ecological risks die to antibiotics and ARGs, this study mainly summarizes research progress about: (i) the occurrence, concentration, fate, and potential ecological effects of antibiotics and ARGs in various aquatic environments, (ii) the threat, spread, and horizontal gene transfer (HGT) of ARGs, and (iii) the relationship between antibiotics, ARGs, and ARB. Finally, this review also proposes future research direction on antibiotics and ARGs.     

多重耐药菌在人类、动物和环境的耐药和传播机制

抗生素等抗菌药物的滥用在全球范围内造成了多重耐药菌的传播。多重耐药菌(Multidrug resistant organisms,MDRO)以及耐药基因(Antibiotic resistance genes,ARGs)可在人类、动物和环境之间进行传播,尤其是ARGs可以通过水平转移的方式在同种属或者不同种属的菌群之间进行传播,使得细菌耐药问题日益严重,耐药机制趋于复杂,疾病治疗更加困难,对人类公众健康造成严重的威胁。因此抗生素等抗菌药物的使用应加以规范。     

水平基因转移介导抗菌素耐药性传播机制的研究进展

近几十年来,病原菌耐药性的出现和蔓延已上升为严峻的公共卫生问题。越来越多研究表明,抗菌素抗性基因(antibiotic resistance genes,ARGs)不仅仅见于临床所分离的病原体,而是包括所有的致病菌、共生菌以及环境中的细菌,它们都能在可移动遗传元件和噬菌体的作用下,通过水平基因转移(horizontal gene transfer,HGT)途径获得耐药性,进而形成抗菌素耐药基因簇(耐药基因组)。HGT可导致抗菌素的耐药性在环境共生菌和病原菌之间传播扩散,这可通过临床上一些重要的抗菌素耐药基因的传播证实。传统观念认为HGT的三种机制中,接合对ARGs的传播影响最大,最近研究表明转化和转导对ARGs播散起到不可忽视的作用。通过深入了解耐药基因组的传播及其在动员病原菌耐药中发挥的作用,对于控制这些基因的播散是至关重要的。将讨论耐药基因组的概念,提供临床相关的抗菌素抗性基因水平基因转移的例子,对当前已研究的促使抗菌素耐药性传播的各种HGT机制进行回顾。     

Antibiotic resistance in surface water ecosystems: Presence in the aquatic environment,prevention strategies,and risk assessment

Antibiotic-resistant bacteria (ARB) have gained increased notoriety due to their continued detection in environmental media and consequently their threat to human and animal health. The continuing spread of antibiotic resistance throughout the environment is of growing environmental and public health concern, making it difficult to treat harmful resistant diseases. This paper examines the presence of antibiotics, ARB, and antibiotic-resistant genes (ARGs) in aquatic environments; the effectiveness of current water treatment strategies to remove them; and risk assessment methods available that can be used to evaluate the risk from antibiotic resistance. Antibiotics, ARB, and ARGs have been reported at varying levels in wastewater treatment plants, hospital wastewater, irrigation water, recreational water, and drinking water. There are many different water treatments capable of reducing antibiotic resistance (including chlorination, UV, and ozone); however, no one method can fully eliminate it with much variation in the reported effects. Risk assessment models can be used for interpreting field data into the risk to human health from antibiotic resistance. Currently, there is no gold standard risk assessment method for evaluating antibiotic resistance. Methods in this area need further development to reflect evolving risk assessment methodologies and dynamic data as it emerges.     

Antibiotic resistance genes in water environment

The use of antibiotics may accelerate the development of antibiotic resistance genes (ARGs) and bacteria which shade health risks to humans and animals. The emerging of ARGs in the water environment is becoming an increasing worldwide concern. Hundreds of various ARGs encoding resistance to a broad range of antibiotics have been found in microorganisms distributed not only in hospital wastewaters and animal production wastewaters, but also in sewage, wastewater treatment plants, surface water, groundwater, and even in drinking water. This review summarizes recently published information on the types, distributions, and horizontal transfer of ARGs in various aquatic environments, as well as the molecular methods used to detect environmental ARGs, including specific and multiplex PCR (polymerase chain reaction), real-time PCR, DNA sequencing, and hybridization based techniques.     

环境中抗生素抗性基因与I型整合子的研究进展

抗生素抗性基因(Antibiotic resistance genes,ARGs)作为一种新型污染物在不同环境中广泛分布、来源复杂,对生态环境和人类健康造成了很大的潜在风险。同时,Ⅰ型整合子(Int Ⅰ)介导的ARGs水平转移是环境中微生物产生耐药性的重要途径,Ⅰ型整合子整合酶基因(intI1)与ARGs丰度在环境中表现出了较高的正相关性,Int Ⅰ可以作为标记物在一定程度上反映ARGs在环境中的迁移转化规律和人类活动影响程度。本文介绍ARGs与Int Ⅰ在环境中的来源与分布,总结Int Ⅰ介导的ARGs迁移转化机制以及相关研究方法,并展望未来的研究发展趋势。