结核分支杆菌耐药基因的研究进展

结核分支杆菌耐药基因的研究进展…………………………………………刘延龙李冀文王孟山结核分支杆菌耐药基因的研究进展@刘延龙@李冀文@王孟山...     

结核分支杆菌trpoB基因克隆与特征

目的 克隆结构分支杆菌rpoB基因。方法 以结核分杆菌rpoB基因保守区的PCR扩增片段为探针从已建立的结核分支杆菌基因文库中筛选rpoB基因。结果 引物TR1，TR2b扩增H37RaDNA的一约411bp片段，经克隆及序列分析表明该片段与结核分支杆菌rpoB基因同源，对约12，000个克隆进行筛选，共获7个可疑阳性克隆，经过再次发校证实其中3个克隆为阳性，其中一个克隆携带约3.8Kb插入片段，一系列内切酶酶切分析后得出该3.8Kb克隆片段的部分限制性切酶酶谱，进一步分析表明所用411bp探针同源序列距两端分别为1Kb和2.8Kb。结论 与报道的结核菌rpoB基因开放阅读框架比较，本文克隆的3.8Kb片段包含结核菌rpoB完整基因的大部分，为进一步研究RFP及其它利福霉素类药物抗结核作用方式及耐药机制奠定基础。     

耐多药结核分支杆菌三种耐药基因检测

报道聚合酶链反应单链构象多态性（ＰＣＲＳＳＣＰ）方法检测耐多药结核分支杆菌ｒＰＯＢ、ｒＰＳＬ和ＫａｔＧ基因突变情况。材料和方法（１）菌株：结核分支杆菌Ｈ３７Ｒｖ参考菌株购自中国菌种保存中心；１０２株结核分支杆菌临床分离株取自本市肺结核患者，常规进...     

我国结核分支杆菌耐药基因的临床应用研究需要深化

多年来贵刊刊登了大量结核分支杆菌分子生物学研究论，受益匪浅，也为我国学在此方面付出的努力和取得的成绩而鼓舞。学习之余有一些不成熟的抛砖之见，愿借贵刊边角之地以求教于智。     

90株非结核分支杆菌耐药情况的分析

目的 观察分析我院１９８６￣１９９７年非结核分支杆菌的耐药情况。方法 对９０株非结核分支杆菌用传统的方法进行菌种鉴定及药敏试验。结果 非结核分支杆菌对ＰＡＳ呈高度的耐药性，对ＳＭ、ＩＮＨ、ＲＦＰ、ＥＢＭ等耐药性也较高，对ＫＭ、ＴＨ较敏感。堪萨斯分支杆菌对抗结核药物较敏感，鸟，胞内、次要、土地、偶然等分支杆菌对抗经物耐药的较多。另外，非结核分支杆菌除对ＰＡＳ的低浓度与高浓度的耐药率较一致外，对其它六     

结核分支杆菌耐药性的研究进展

结核分支杆菌耐药是指原来对于抗结核药物敏感的结核分支杆菌变得不敏感或产生了耐受性,它是结核病防治工作中遇到的一个棘手和重要的问题。随着人们对结核病的认识不断提高,结核病在治疗过程中遇到的新的问题和挑战也越来越多,结核菌耐药菌株越来越强和多耐药结核菌的不断增多     

结核分支杆菌五种耐药基因检测的临床应用及评价

目的　检测结核分支杆菌rpoBkatG、rpsL、pncA和embB耐药基因 ,评价其临床应用价值。方法　采用聚合酶链反应 单链构象多态性 (PCR SSCP)分析和药敏试验 (比例法 ) ,了解 10 9例肺结核患者结核分支杆菌耐药情况 ,并分析、比较临床治疗效果。结果　 1/ 2以上的肺结核患者至少耐两种抗结核药物 ,对RFP、INH、SM、PZA和EB总耐药率分别为 80 7%、71 5 %、78 8%、5 7 7%和48 6%。rpoB、katG、rpsL、pncA和embB基因突变率分别为 76%、68%、71%、5 1%和 3 0 %。结核分支杆菌耐药基因突变率与耐药水平联系密切 ,多数结核分支杆菌耐药基因突变易发生在高耐药株 ,也有少数基因突变发生在低耐药株。根据药敏试验和耐药基因检测结果 ,6个月耐多药结核治愈率分别达到 5 4 8%和 62 8% ,治疗效果满意 ,两种方法差异无显著性 (P >0 0 5 )。结论　耐药基因检测指导治疗是一种新探索 ,PCR SSCP方法敏感、特异 ,可以快速检测结核分支杆菌rpoB、katG、rpsL、pncA和embB耐药基因突变 ,可能会成为临床指导用药的好方法     

90株非结核分支杆菌耐药情况的分析

目的观察分析我院1986~1997年非结核分支杆菌的耐药情况?方法对90株非结核分支杆菌用传统的方法进行菌种鉴定及药敏试验?结果非结核分支杆菌对PAS呈高度的耐药性,对SM?INH?RFP?EBM等耐药性也较高,对KM?TH较敏感?堪萨斯分支杆菌对抗结核药物较敏感,鸟?胞内?次要?土地?偶然等分支杆菌对抗结核药物耐药的较多?另外,非结核分支杆菌除对PAS的低浓度与高浓度的耐药率较一致外,对其它六种药物低?高浓度的耐药率有较大差异?说明许多非结核杆菌对抗结核药物呈天然的抗药性?结论针对以上情况,有待解决的是研制新药与更有效的治疗手段。     

非结核分枝杆菌相关研究新进展

非结核分枝杆菌在自然界中广泛存在,部分可引起人类疾病.因非结核分枝杆菌对多种抗结核药物耐药,且诊断困难、患者预后较差,使非结核分枝杆菌感染性疾病逐渐成为医学界十分关注的研究课题.作者从非结核分枝杆菌种类及感染率、非结核分枝杆菌耐药情况及耐药机制研究、非结核分枝杆菌感染特点及治疗方案、非结核分枝杆菌检测方法及环境水非结核分枝杆菌污染研究等方面综述了非结核分枝杆菌相关的研究进展.其耐药机制及传播机制尚未阐明,需要进行深入研究.     

Pathogenesis of nontuberculous mycobacteria infections

M avium is a microorganism well adapted to living in the environment and in different hosts. During the past 15 years, a substantial amount of information has been accumulated about the mechanisms used by M avium to cross the host's mucosal barrier, replicate inside cells, circumvent the host's immune response, and persist inside the host. It turns out that M avium is a fascinating pathogen after all. The increasing knowledge about M avium pathogenesis may one day provide means for a more effective prophylaxis as well as for treatment of the infection.     

Laboratory diagnosis of nontuberculous mycobacteria

In conclusion, it is important to realize that there is no "stand alone" assay for the identification of NTM. Many new species may not be recognized in all assays. Newer molecular tests are more accurate for identification than phenotypic tests and have significantly improved turnaround time. Clinical significance of an isolate should be determined, however, before committing resources for the identification of a mycobacterial isolate to the species level. In addition, there are significant differences in the range and quality of services provided by different laboratories. Today, techniques and equipment are increasingly complex and costly, making it more difficult to upgrade every local laboratory to perform these assays. But because specimen delivery and communication of results can be rapidly and easily achieved, utilization of reference laboratories for rarely performed sophisticated tests is a more practical approach.     

Molecular diagnosis of nontuberculous mycobacteria

PURPOSE OF REVIEW: Diagnosis of infection due to nontuberculous mycobacteria is not easy, as it must be distinguished from colonization or contamination by other nontuberculous mycobacteria. Molecular methods offer many advantages over conventional methods of identification. The results are obtained rapidly, are reliable and reproducible, and even mixed or contaminated cultures can be examined. This review highlights the recent advances in molecular techniques for identification of nontuberculous mycobacteria. RECENT FINDINGS: Nontuberculous mycobacteria are ubiquitous towards the environment and have the potential to colonize and cause serious infection. An increasing number of species and clinical presentations are being described, and progress has been made towards the understanding of the underlying predisposing factors. Disease caused by nontuberculous mycobacteria is often associated with various forms of immunosuppression, particularly HIV infection, whereas mild forms of immune defects have been observed in some patients who, apart from their nontuberculous mycobacterial disease, seem to be healthy on initial examination. Molecular techniques have shown their usefulness for the identification of most mycobacteria. Probes are widely used in clinical laboratories for the identification of the most common mycobacterial species. Because automated DNA sequencing and the programs for analysing sequence data have become technically simpler, polymerase chain reaction-based sequencing is now used in many mycobacterial reference laboratories as a routine method for species identification. SUMMARY: Significant advances have been made with molecular tools for diagnosis of mycobacteria. The DNA microarray technique holds great promise for the future because it is easy to perform, it can be readily automated, and it allows the identification of a large number of mycobacterial species in one reaction.     

Pulmonary infection with nontuberculous mycobacteria

Nontuberculous mycobacterial infections (NTM) are being increasingly recognized as a cause of chronic pulmonary disease. We recently reviewed the clinical, radiologic, and bacteriologic presentation of 89 adult patients ill enough to have been hospitalized between 1981 and 1985 with the diagnosis of NTM. Preexisting lung disease was present in 82% and alcohol abuse in 40%. Although M. avium complex was identified in 51% of the patients, M. xenopi, which is usually reported to occur infrequently, accounted for 38% of our cases and M. kansasii for only 9%. Treatment was limited by a high incidence of associated disease, in vitro drug resistance, drug toxicity, and a mortality rate of 32% within 18 months of admission. Nevertheless, bacteriologic conversion occurred in 29% of those treated. M. xenopi appears to be an important pathogen in southern Ontario. It differs from the other NTM by having a different pattern of in vitro drug resistance but not by its clinical or radiologic presentation.     

Pulmonary disease due to nontuberculous mycobacteria

Nontuberculous mycobacteria (NTM) are increasingly associated with pulmonary disease. This is a worldwide phenomenon and one that is not related just to better diagnostic techniques or HIV infection. The mode of transmission of NTM is not well defined, but environmental exposure may be the major factor. While most exposed and infected individuals never acquire NTM disease, some ostensibly immunocompetent persons will. Although our understanding of the pathogenesis of NTM disease is incomplete, we believe that both host and mycobacterial factors are involved. Among the former, interferon-gamma"trafficking" may well play a central role. When disease occurs, it is likely to present in one of three prototypical forms: a tuberculosis-like pattern often affecting older male smokers with COPD; nodular bronchiectasis classically occurring in middle-aged or older women who never smoked and present with cough; and hypersensitivity pneumonitis following environmental exposure. While Mycobacterium avium complex has been described with all three forms, many other NTM can produce one or another of them; variants of these prototypes also exist. Diagnosis of NTM disease relies on microbiology and chest CT scanning, and criteria to aid diagnosis are available. Treatment of disease depends on the species involved, extent and form of disease, and overall condition of the patient. Surgery for localized disease may be useful for those species expected to be refractory to medical therapy. Observation without treatment may be appropriate for some patients with slowly progressive disease that is expected to be particularly difficult to treat.     

Mycobacterial infections caused by nontuberculous mycobacteria

The purpose of this review is to familiarize a broad range of medical professionals with a relatively new and growing problem of infections caused by mycobacteria other than M. tuberculosis and M. leprae. There are at least 60 mycobacterial species that have been identified as causative agents of diseases in humans. They are all environmental bacteria, and they are not transmitted from person to person. The usual source of infection is water, soil, and aerosols developed from these sources. The probability of contracting such a disease depends not only on the closeness of interaction with an environment containing an enhanced concentration of bacteria but also and foremost on the sensitivity of an individual to these infections, which may depend on the state of immunity and other so-called predisposing conditions. Therefore, these infections are often referred to as opportunistic, and the group of organisms causing them are usually referred to as nontuberculous mycobacteria (NTM). This review addresses in a condensed form various aspects of these infections, including bacteriology, clinical manifestations, diagnosis, and therapy. The reader will be able to find more details on each of these topics in several reviews and some original papers cited in this article.     

Pulmonary disease caused by nontuberculous mycobacteria

Nontuberculous mycobacterial pulmonary infections have become more common in recent years. The diagnosis is often overlooked because the findings may be subtle or because the radiographic appearance may change slowly or not at all for long periods of time. As a rule, the radiographic findings of nontuberculous mycobacterial pulmonary infections are identical to those of tuberculosis in any given patient. Cavitary disease in nontuberculous mycobacterial infections is less common than in tuberculosis. The most common radiographic finding is one or more areas of clustered fibroproductive nodules that change slowly. Mycobacterium kansasii infection responds well to therapy, whereas M avium-intracellulare infection is difficult to treat. Awareness of the radiographic appearance of the nontuberculous mycobacterial pulmonary infections will facilitate their diagnosis so that appropriate therapy may be initiated before the disease is far advanced.     

Nosocomial infections due to nontuberculous mycobacteria.

Nontuberculous mycobacteria (NTM) are ubiquitous in the environment and cause colonization, infection, and pseudo-outbreaks in health care settings. Data suggest that the frequency of nosocomial outbreaks due to NTM may be increasing, and reduced hot water temperatures may be partly responsible for this phenomenon. Attention to adequate high-level disinfection of medical devices and the use of sterile reagents and biologicals will prevent most outbreaks. Because NTM cannot be eliminated from the hospital environment, and because they present an ongoing potential for infection, NTM should be considered in all cases of nosocomial infection, and careful surveillance must be used to identify potential outbreaks. Analysis of the species of NTM and the specimen source may assist in determining the significance of a cluster of isolates. Once an outbreak or pseudo-outbreak is suspected, molecular techniques should be applied promptly to determine the source and identify appropriate control measures.     

Overview of respiratory infection caused by nontuberculous mycobacteria

Recently, the clinical importance of nontuberculous mycobacteria (especially, Mycobacterium avium complex [MAC] respiratory infection) has been increasing. In addition, an official ATS/IDSA statement about diagnosis, treatment, and prevention of nontuberculous mycobacterial diseases has been published in February, 2007. In this review article, essence of this official statement will be introduced. In MAC respiratory infection, (i) primarily fibrocavitary disease, (ii) nodular/bronchiectatic disease, and (iii) hypersensitivity-like disease are identified, and (i) and (ii) are clinically important. Primarily fibrocavitary disease is characterized by cavitary lesions in upper lung fields in elderly subjects, smoking patients, or patients with pneumoconiosis. Nodular/bronchiectatic disease is characterized by centrilobular nodules and diffuse bronchiectases in the right middle lobe and the left lingula in middle-aged women. In addition, disseminated MAC disease in patients with acquired immunodeficiency syndrome should be considered. Further studies concerning transmission route as well as mechanism of MAC disease should be performed.