Disinfectant-resistant mycobacteria

性状（由申请方提供）：非结核分枝杆菌属。在环境中普遍存在，并在全世界的卫生保健环境中引起感染和假感染。其中，快速生长的分枝杆菌（RGM）、M.（subsp.和subsp. Escherichiense）、M. chelonae和M.由于它们在医院水源中的普遍存在以及治疗它们引起的感染的困难，偶然性尤其成问题。越来越多的人认识到M。刺叶藓特别是作为新兴病原体的黑胫病菌和黑胫病菌。特别值得关注的是，耐戊二醛的RGM与医院内爆发相关的频率越来越高，有时达到流行病的比例，如最近在巴西记录的那样。戊二醛（GTA）是全球医院中热敏医疗器械使用最广泛的化学消毒剂。 已知的这种消毒剂在其他细菌中的作用模式表明，导致GTA结合和/或渗透减少的细胞包膜表面暴露组成的变化可能是RGM产生高水平抗性的机制之一。由于分枝杆菌外膜在药物敏感性和宿主-病原体相互作用中发挥的重要作用，因此存在一些担忧，即在临床环境中广泛使用GTA和相关醛类消毒剂会影响RGM耐药群体的选择，可能会对药物交叉耐药性和致病性产生影响。为了支持这些假设，我们最近证明，减少孔蛋白表达是M。smegalgae和M.龟类对GTA和另一种醛类消毒剂邻苯二甲醛（OPA）产生高水平的抗性。部分由于孔蛋白表达缺陷，GTA/OPA耐药M.研究中的龟分离物还显示出对多种药物的异常高水平的耐药性，所述药物包括利福平、环丙沙星、克拉霉素、红霉素、万古霉素、四环素和利奈唑胺。此外，我们的初步结果表明，与GTA敏感的参考M。辽宁省流行M.来自巴西的Eschliense分离株显示出对氨基糖苷类药物的不寻常的抗性，并且在小鼠中的致病性大大增加。 我们已经收集了一批抗GTA的M。chelonae和M.黑腹蛛亚种在世界不同地区引起医院感染和假性感染的病原体。事实上，并非所有这些分离株都显示出对OPA的交叉耐药性（与M。上述龟分离物）表明分枝杆菌中一定存在一种以上对醛类消毒剂的抗性机制。我们建议使用我们收集的临床分离株，结合基因组学，转录组学，遗传学和生物化学的方法来研究RGM的耐药性的分子机制，以氯代乙酰胺为基础的消毒剂，并研究这些菌株所经历的表型变化可能对他们的药物敏感性和致病性的潜在影响。本研究的结果可能导致医疗器械消毒的优化策略的实施，并建议更有效的治疗方法来治愈由耐消毒剂菌株引起的医院感染。 公共卫生相关性：我们建议阐明院内快速生长的分枝杆菌病原体对醛类消毒剂的耐药性机制，并研究耐药菌株对其药物敏感性和致病性的表型变化的影响。

DESCRIPTION (provided by applicant):Non-tuberculous Mycobacterium spp. are ubiquitous in the environment and cause infections and pseudo-infections in health care settings throughout the world. Among these, the rapidly-growing Mycobacterium (RGM) species, M. abscessus (subsp. abscessus and subsp. massiliense), M. chelonae, and M. fortuitum are particularly problematic due to their ubiquitous presence in hospitals' water sources and the difficulty of treating the infections they cause. There is increasing awareness of M. abscessus subspp. abscessus and massiliense in particular as emerging pathogens. Of particular concern is the increasing frequency with which glutaraldehyde-resistant RGM are being associated with nosocomial outbreaks, sometime reaching epidemic proportions as recently documented in Brazil. Glutaraldehyde (GTA) is the most widely used chemical disinfectant for heat-sensitive medical devices in hospitals worldwide. What is known of the mode of action of this disinfectant in other bacteria suggests that changes in the surface-exposed composition of the cel envelope resulting in decreased binding and/or penetration of GTA may be one of the mechanisms through which RGM develop high levels of resistance. Because of the important role played by the mycobacterial outer membrane in drug susceptibility and host-pathogen interactions, there is thus some concern that the widespread use of GTA and related aldehyde disinfectants in clinical settings is impacting on the selection of resistant populations of RGM with possible consequences on cross-resistance to drugs and pathogenicity. In support of these assumptions, we recently demonstrated that reduced porin expression was one of the mechanisms through which M. smegmatis and M. chelonae develop high levels of resistance to GTA and a further aldehyde disinfectant, ortho-phthalaldehyde (OPA). In part due to defects in porin expression, the GTA/OPA-resistant M. chelonae isolate under study also displayed unusually high levels of resistance to a number of drugs including rifampicin, ciprofloxacin, clarithromycin, erythromycin, vancomycin, tetracycline and linezolid. Further, our preliminary results indicate that, compared to a GTA-susceptible reference M. massiliense clinical isolate, the epidemic M. massiliense isolates from Brazil display unusual resistance to aminoglycosides and much increased pathogenicity in mice. We have assembled a collection of GTA-resistant isolates of M. chelonae and M. abscessus subsp. massiliense responsible for nosocomial infections and pseudo-infections in different regions of the world. The fact that not all of these isolates display cross-resistance to OPA (unlike the M. chelonae isolate described above) indicates that there must exist more than one mechanism of resistance to aldehyde disinfectants in mycobacteria. We propose to use our collection of clinical isolates together with a combination of genomic, transcriptomic, genetic and biochemical approaches to investigate the molecular mechanisms of resistance of RGM to aldehyde-based disinfectants and to study the potential impact the phenotypic changes undergone by these strains might have had on their susceptibility to drugs and pathogenicity. The results of this study could lead to the implementation of optimized strategies for the disinfection of medical devices and suggest more efficient treatments to cure those nosocomial infections caused by disinfectant-resistant isolates. PUBLIC HEALTH RELEVANCE: We propose to elucidate the mechanisms of resistance of nosocomial rapidly-growing mycobacterial pathogens to aldehyde disinfectants and to study the impact of the phenotypic changes undergone by resistant isolates on their susceptibility to drugs and pathogenicity.