细菌耐药机制及耐药性消除的研究进展

抗菌药物选择压力导致细菌耐药性日趋严重。究其根源,细菌耐药机制的探讨是为了揭示菌株耐药的根本原理,并从中找到消除耐药性的有效方法。本研究就现今国内外对耐药机制的研究以及耐药性消除的研究进行综述。     

动物源细菌耐药性研究现状与对策

目前我国动物源细菌耐药现象十分普遍,多重耐药甚至泛耐药的菌株不断出现,给公共卫生和食品安全造成了重大威胁。文中从我国动物源耐药性研究的主要问题、细菌耐药性形成和传播机制以及耐药性防控策略等几个方面进行综述,以期为耐药性的研究和防控提供参考。     

15年前后细菌L型临床耐药性的变迁

目的检测15年前后细菌L型临床耐药性的变迁,分析影响因素,指导临床用药。方法对新乡市中心医院15年来临床检出的常见细菌L型菌株逐个进行药敏监测,逐年进行耐药性变化分析研究。结果1990年至1999年细菌L型常见菌株耐药性逐年上升,特别是青霉素类大部耐药;2000年至2005年,耐药性趋势变缓,青霉素类耐药率有所下降。结论合理应用抗生素,不滥用抗生素是细菌L型耐药性变迁的重要原因,药物敏感试验是良好的监测方法。     

名词解释

耐药性病原微生物失去对某种药物(包括抗菌素)的敏感性,即增强了对药物的耐受能力,称之为耐药性或抗药性。耐药菌株的产生,有人认为有自发变异菌存在,敏感菌被杀死或受抑制后,自发变异体更容     

218例表皮葡萄球菌的耐药性分析

目的了解3年内218例表皮葡萄球菌的耐药性,指导临床合理使用抗生素,方便临床采取更有效的治疗措施。方法对2007年1月至2009年12月间盛泽医院218例感染患者的各个感染部位进行表皮葡萄球菌的分离和耐药性检测,根据药物敏感试验结果来分析其耐药性的变化。结果 218株分离的表皮葡萄球菌中,耐甲氧西林菌株(MRSE)160株,占总数的73.4%,甲氧西林敏感菌株(MSSE)58株,占26.6%,未发现对万古霉素耐药的菌株,MRSE对大部分抗生素有较高的耐药率,MSSE则对大多数抗生素保持较低的耐药率。结论表皮葡萄球菌的分布广泛,耐药情况日趋严重,合理使用抗菌药物以延缓细菌耐药性的产生非常重要。     

耐药结核菌超微结构的观察

细菌的耐药性是细菌对药物产生适应或细菌发生变异的后果。目前应用的抗结核药物已达14种之多,随着抗结核药物的相继问世,耐药性的问题也就显得更加突出了。国内学者对耐药菌的生物学性状,致病力及耐药发生的     

粤北地区仔猪腹泻大肠杆菌分离鉴定及耐药性分析

为了解粤北地区规模化猪场仔猪腹泻大肠杆菌耐药情况,为该病防控提供用药参考,对来自6个规模化猪场疑似仔猪大肠杆菌引起的腹泻粪便和肠道内容物进行了大肠杆菌分离鉴定,对分离鉴定的40株大肠杆菌进行了药敏试验。结果表明,分离菌株对22种受试药物均产生不同程度耐药性,强力霉素和四环素耐药菌株比例最高,达到97.5%,其次是复方新诺明、庆大霉素、氯霉素和红霉素耐药菌株达到80%以上。敏感性最高的药物为丁胺卡那霉素,其次是头孢西丁,敏感菌株比例分别为85%和84.5%。试验菌株均产生不同程度多重耐药性,最少为4重耐药性,10重及以上耐药性菌株比例达到80%以上。研究表明,粤北地区仔猪腹泻大肠杆菌耐药性严重,要重视药敏监测,以指导合理选用药物防控该病。     

ICU病房产超广谱β-内酰胺酶肺炎克雷伯菌的监测和耐药性分析

了解产超广谱β-内酰胺酶(ESBLs)肺炎克雷伯菌的耐药性,为临床合理使用抗菌药物提供依据。采用自动化细菌鉴定仪(法国生物梅里埃公司Vitek-2和BD Phonenix 100)进行细菌鉴定和药敏试验,应用WHO-NET5.4软件进行耐药性分析。ICU病房共分离出100株肺炎克雷伯菌,其中产ESBLs株48株,占48%,药敏结果显示产ESBLs菌株的耐药率普遍高于不产ESBLs株,产ESBLs株对氨苄西林、头孢呋辛、头孢唑啉等全部耐药,对头孢曲松、头孢噻肟的耐药率也大于80%,对氨基糖苷类的庆大霉素、四环素,对喹诺酮类的环丙沙星、左氧氟沙星以及磺胺类中的复方新诺明耐药率较高(均大于55%),对哌拉西林/他唑巴坦、阿米卡星、头孢西丁等耐药率较低,对亚胺培南、美洛培南高度敏感。产ESBLs肺炎克雷伯菌耐药现象严重,及时监测产ESBLs菌的发生率及其耐药趋势,为临床合理应用抗菌药物,延缓细菌耐药性的产生,控制医院感染具有重要意义。     

主要医院感染病原菌与社区感染株耐药性比较

目的比较主要医院感染(HAI)病原菌与社区感染(CAI)株的耐药性,指导合理使用抗菌药物。方法收集永康市第一人民医院2003年1月至2006年6月所有标本中分离的主要HAI菌及其CAI株,分别统计其药物敏感试验。采用美国Dade Behring Microscan Walkaway 40全自动细菌鉴定及药敏测试仪及其配套药敏鉴定板测定MIC值。全国医院感染监测网软件和χ2统计分析。结果主要HAI菌为前4种革兰阳性(G )菌依次是金黄色葡萄球菌、表皮葡萄球菌、屎肠球菌、溶血葡萄球菌,前5种革兰阴性(G-)菌依次是大肠埃希菌、肺炎克雷伯菌、鲍曼不动杆菌、铜绿假单胞菌、阴沟肠杆菌。HAI株耐药率普遍高于CAI株,不同的细菌耐药率各具特点。不论HAI株还是CAI株,G 菌对万古霉素的耐药率最低,G-菌对亚胺培南的耐药率均较低,且两者耐药率差异均无显著性。金黄色葡萄球菌、大肠埃希菌、肺炎克雷伯菌、鲍曼不动杆菌4种HAI株对大多数抗菌药物的耐药率明显高于CAI株,其余5种细菌HAI株仅对少数抗菌药物的耐药率高于CAI株。结论HAI菌株耐药性比CAI菌株强,临床应区分感染性质合理使用抗菌药物,有针对性控制感染,从而减少抗菌药物的滥用和细菌耐药性的产生。     

头孢曲松耐药菌通过调整能量代谢相关蛋白产生耐药性

随着抗生素药物的开发与利用,细菌在对抗药物过程中逐渐发展出各种不同的耐药机制.近年来高通量的蛋白质组学技术已逐渐用于细菌耐药性机理研究,但主要集中在对细菌外膜蛋白的作用进行分析.本文采用2-D native/SDS PAGE方法从蛋白质复合物角度分析接近生理条件的胞浆蛋白在头孢曲松耐药性中的作用.结果发现8个耐药性相关蛋白质,通过对蛋白质功能分析,揭示了细菌通过调整能量代谢相关蛋白产生耐药性的新机制.进一步对相关菌株的次抑菌浓度和生存率分析,提示MalP和SucC等关键蛋白质可作为设计和开发新型抗菌分子的作用靶点.     

A Locked Nucleic Acid (LNA)-Based Real-Time PCR Assay for the Rapid Detection of Multiple Bacterial Antibiotic Resistance Genes Directly from Positive Blood Culture

Bacterial strains resistant to various antibiotic drugs are frequently encountered in clinical infections, and the rapid identification of drug-resistant strains is highly essential for clinical treatment. We developed a locked nucleic acid (LNA)-based quantitative real-time PCR (LNA-qPCR) method for the rapid detection of 13 antibiotic resistance genes and successfully used it to distinguish drug-resistant bacterial strains from positive blood culture samples. A sequence-specific primer-probe set was designed, and the specificity of the assays was assessed using 27 ATCC bacterial strains and 77 negative blood culture samples. No cross-reaction was identified among bacterial strains and in negative samples, indicating 100% specificity. The sensitivity of the assays was determined by spiking each bacterial strain into negative blood samples, and the detection limit was 1–10 colony forming units (CFU) per reaction. The LNA-qPCR assays were first applied to 72 clinical bacterial isolates for the identification of known drug resistance genes, and the results were verified by the direct sequencing of PCR products. Finally, the LNA-qPCR assays were used for the detection in 47 positive blood culture samples, 19 of which (40.4%) were positive for antibiotic resistance genes, showing 91.5% consistency with phenotypic susceptibility results. In conclusion, LNA-qPCR is a reliable method for the rapid detection of bacterial antibiotic resistance genes and can be used as a supplement to phenotypic susceptibility testing for the early detection of antimicrobial resistance to allow the selection of appropriate antimicrobial treatment and to prevent the spread of resistant isolates.     

综述与专论：细菌的信号转导系统及其在耐药中的作用

耐药菌的日益增多给临床治疗带来巨大的困难,揭示耐药机制成为遏制耐药菌的基本环节。细菌的信号系统是菌体之间信息交流的主要渠道,在调控细菌耐药性方面发挥重要的作用。本文梳理了细菌双组分系统、群体感应系统、第二信使、吲哚等细菌信号系统(分子)与细菌耐药性的关系,总结了各信号系统调控细菌耐药性的机制和途径,包括调控生物膜的形成、调节药物外排泵的活性、激活抗生素灭活酶、提高耐药基因表达水平、促进耐药基因转移、修饰细胞壁结构等,涉及到细菌耐药的多个环节。各信号系统不仅可以独立调控耐药,还可以互相作用,形成调控网络,从多个层面调节细菌耐药性。因此,靶向细菌信号系统,阻断菌体之间的信号联络,有望成为遏制细菌耐药性日益严重的新策略。     

Defective DNA repair as a potential mechanism for the rapid development of drug resistance in Plasmodium falciparum

The development and spread of highly drug-resistant parasites pose a central problem in the control of malaria.Understanding mechanisms that regulate genomic stability, such as DNA repair, in drug-resistant parasites and during drug treatment may help determine whether this rapid onset of resistance is due to an increase in the rate at which resistance-causing mutations are generated. This is the first report to demonstrate DNA repair activities from the malaria-causing parasite Plasmodium falciparum that are specific for ultraviolet light-induced DNA damage. The efficiency of DNA repair differs dramatically among P. falciparum strains with varying drug sensitivities. Most notable is the markedly reduced level of repair in the highly drug-resistant W2 isolate, which has been shown to develop resistance to novel drugs at an increased rate when compared to drug-sensitive strains. Additionally, the antimalarial drug chloroquine and other quinoline-like compounds interfered with the DNA synthesis step of the repair process, most likely a result of direct binding to repair substrates. We propose that altered DNA repair, either through defective repair mechanisms or drug-mediated inhibition, may contribute to the accelerated development of drug resistance in the parasite.     

‘To be,or not to be’—The dilemma of ‘silent’ antimicrobial resistance genes in bacteria

Antimicrobial resistance is a serious threat to public health that dramatically undermines our ability to treat bacterial infections. Microorganisms exhibit resistance to different drug classes by acquiring resistance determinants through multiple mechanisms including horizontal gene transfer. The presence of drug resistance genotypes is mostly associated with corresponding phenotypic resistance against the particular antibiotic. However, bacterial communities harbouring silent antimicrobial resistance genes—genes whose presence is not associated with a corresponding resistant phenotype do exist. Under suitable conditions, the expression pattern of such genes often revert and regain resistance and could potentially lead to therapeutic failure. We often miss the presence of silent genes, since the current experimental paradigms are focused on resistant strains. Therefore, the knowledge on the prevalence, importance and mechanism of silent antibiotic resistance genes in bacterial pathogens are very limited. Silent genes, therefore, provide an additional level of complexity in the war against drug-resistant bacteria, reminding us that not only phenotypically resistant strains but also susceptible strains should be carefully investigated. In this review, we discuss the presence of silent antimicrobial resistance genes in bacteria, their relevance and their importance in public health.     

Survey of drug and phage resistance and colicin and hemolysin production among coliforms isolated in the Ivory Coast.

Analysis of 178 strains isolated as total and fecal coliforms in the Ivory Coast revealed that (i) hemolytic activity was scarce (0.6%) among this bacterial population; (ii) the most prevalent colicins detected were, in decreasing order, E, I, A, and G; (iii) the frequency of coliphage and drug resistance was similar to that observed in other countries, except for those of drug-resistant strains in animal feces, which were lower than in countries where animals are antibiotic fed; and (iv) one of the drug resistance plasmids seemed to possess a restriction-modification system and another seemed to code for capsular material.     

细菌的信号转导系统及其在耐药中的作用

耐药菌的日益增多给临床治疗带来巨大的困难,揭示耐药机制成为遏制耐药菌的基本环节.细菌的信号系统是菌体之间信息交流的主要渠道,在调控细菌耐药性方面发挥重要的作用.本文梳理了细菌双组分系统、群体感应系统、第二信使、吲哚等细菌信号系统(分子)与细菌耐药性的关系,总结了各信号系统调控细菌耐药性的机制和途径,包括调控生物膜的形成...     

Survey of drug and phage resistance and colicin and hemolysin production among coliforms isolated in the Ivory Coast

Analysis of 178 strains isolated as total and fecal coliforms in the Ivory Coast revealed that (i) hemolytic activity was scarce (0.6%) among this bacterial population; (ii) the most prevalent colicins detected were, in decreasing order, E, I, A, and G; (iii) the frequency of coliphage and drug resistance was similar to that observed in other countries, except for those of drug-resistant strains in animal feces, which were lower than in countries where animals are antibiotic fed; and (iv) one of the drug resistance plasmids seemed to possess a restriction-modification system and another seemed to code for capsular material.     

耐药菌在人-动物-环境中的传播和遗传机制

我国细菌耐药现象十分普遍,多重耐药甚至泛耐药的菌株不断出现,给公共卫生和食品安全造成了重大威胁。随着人类活动以及农业畜牧业的发展,在物理和生物作用力之下,医疗行业和养殖业对环境产生了很大的负面影响,导致养殖动物及其相关环境中存在大量的耐药基因/耐药细菌。医疗行业、动物养殖、自然环境三者在耐药菌的传播和发展中是相互影响、互相作用的有机整体,耐药基因可以借助基因水平转移等方式在人、动物和环境中循环传播,增加了人类摄入耐药基因的风险。面对此类公共卫生问题,传统单一化的卫生工作系统已很难有效地解决这类挑战,急需多学科、多领域的合作来共同应对。文中对我国临床、动物和环境中的细菌耐药现状以及耐药菌在其中的传播和遗传机制进行了综述,以期为细菌耐药研究提供参考。     

结核分枝杆菌的耐药基因及其相关分子机制

结核分枝杆菌原发性和继发性耐药是当前控帝】和治疗结核病面临的重要问题,随着分子遗传学的发展,已经阐明了结核分枝杆菌耐药的分子基础是染色体的突变,影响了药靶本身或激活了药物前体的细菌酶,造成MTB的耐药。本文主要就MTB对其常用药物的耐药机制展开讨论,以便正确认识MTB对不同药物的耐药机制,建立快速检测耐药结核分枝杆菌基因型的分子生物学方法。     

Tentative Method for the Qualitative Detection and Quantitative Assessment of Air Contamination by Drugs

A method for detecting and measuring air contamination by drugs is described which uses an electrostatic bacterial air sampler, sprayers for micronizing drugs, and Mueller-Hinton medium seeded with a highly susceptible strain of Sarcina lutea. Three antibiotics (penicillin, tetracycline, aminosidine) and a sulfonamide (sulfapyrazine) were identified by pretreating portions of medium, showing no bacterial growth, with penicillinase or p-aminobenzoic acid solution and subsequently determining how both drug(-) susceptible and drug-resistant strains of Staphylococcus aureus were affected by this pretreatment. Quantitative determinations were also attempted by measuring the size of the inhibition zones.