中文摘要：噬菌体是生物圈中最丰富的生物实体。噬菌体由于其宿主特异性和快速杀灭细菌的能力，在医疗保健方面有许多潜在的应用，包括抗生素耐药细菌的治疗。寝毛噬菌体的感染需要适当旋转的细菌鞭毛丝。鞭毛依赖性噬菌体chi感染致病性肠杆菌沙门氏菌的血清型。但是，迄今尚未发现与chi感染其他阶段有关的细胞表面受体和蛋白质。本文通过在接种噬菌体chi的软琼脂平板上发现突变体，并监测其生长和体现抗噬菌体突变的形成游动环的能力，筛选到一个鼠伤寒沙门氏菌多基因缺失文库。通过相应的单基因缺失突变体的表型特征，进一步研究了对chi感染力重要的多基因缺失区。通过这种方式，确定了对chi具有不同程度抗性的运动突变体。编码AcrABZ-TolC多药外排系统的单个基因的缺失大大减少了噬菌体chi的感染。此外，acrABtolC三重缺失菌株对chi具有完全的抗性。当编码分子伴侣触发因子的tig基因缺失时，感染严重减少，但并未完全阻断。最后，若编码参与抗氧化剂谷胱甘肽（GSH）和尿酸合成酶基因缺失时，感染力降低。该研究阐明了寝毛噬菌体感染后期所涉及的知之甚少的过程，并为旨在使用噬菌体对抗抗生素耐药细菌感染的研究提供信息。
重要性：抗菌素耐药性在医疗保健领域备受关注。随着更多多药耐药细菌病原体的出现，人们正在探索消除细菌感染的其他技术。其中包括噬菌体疗法，即用特异性噬菌体组合治疗感染。通常，噬菌体通过细胞附属物和表面受体初始附着于其宿主。寝毛噬菌体特别受人关注，因为鞭毛在细菌毒性中非常重要，它们在不降低毒力的情况下使得噬菌体难以附着。该研究发现了多药外排泵对寝毛噬菌体感染肠沙门氏菌的重要性。理论上，如果细菌病原体通过改变外排泵的表达而产生噬菌体抗性，则病原体将同时对泵的抗生素底物更敏感。因此，抗生素和寝毛嗜性噬菌体联合使用可能是特别有效的抗菌疗法。
外文摘要：Bacteriophages are the most abundant biological entities in the biosphere. Due to their host specificity and ability to kill bacteria rapidly, bacteriophages have many potential health care applications, including therapy against antibiotic-resistant bacteria. Infection by flagellotropic bacteriophages requires a properly rotating bacterial flagellar filament. The flagella-dependent phage chi (chi) infects serovars of the pathogenic enterobacterium Salmonella enterica. However, cell surface receptors and proteins involved in other stages of chi infection have not been discovered to date. We screened a multigene deletion library of S. enterica serovar Typhimurium by spotting mutants on soft agar plates seeded with bacteriophage chi and monitoring their ability to grow and form a swim ring, a characteristic of bacteriophage-resistant motile mutants. Those multigene deletion regions identified to be important for chi infectivity were further investigated by characterizing the phenotypes of corresponding single-gene deletion mutants. In this way, we identified motile mutants with various degrees of resistance to chi. Deletions in individual genes encoding the AcrABZ-TolC multidrug efflux system drastically reduced infection by bacteriophage chi. Furthermore, an acrABtolC triple deletion strain was fully resistant to chi. Infection was severely reduced but not entirely blocked by the deletion of the gene tig, encoding the molecular chaperone trigger factor. Finally, deletion in genes encoding enzymes involved in the synthesis of the antioxidants glutathione (GSH) and uric acid resulted in reduced infectivity. Our findings begin to elucidate poorly understood processes involved in later stages of flagellotropic bacteriophage infection and inform research aimed at the use of bacteriophages to combat antibiotic-resistant bacterial infections.
   IMPORTANCE Antimicrobial resistance is a large concern in the health care field. With more multidrug-resistant bacterial pathogens emerging, other techniques for eliminating bacterial infections are being explored. Among these is phage therapy, where combinations of specific phages are used to treat infections. Generally, phages utilize cell appendages and surface receptors for the initial attachment to their host. Phages that are flagellotropic are of particular interest because flagella are often important in bacterial virulence, making resistance to attachment of these phages harder to achieve without reducing virulence. This study discovered the importance of a multidrug efflux pump for the infection of Salmonella enterica by a flagellotropic phage. In theory, if a bacterial pathogen develops phage resistance by altering expression of the efflux pump, then the pathogen would simultaneously become more susceptible to the antibiotic substrates of the pump. Thus, coadministering antibiotics and flagellotropic phage may be a particularly potent antibacterial therapy.
外文关键词：antibiotic resistance；bacteriophage therapy；flagellar motility
作者：Esteves, NC；Porwollik, S；McClelland, M；Scharf, BE
作者单位：Virginia Polytech Inst & State Univ；Univ Calif Irvine
期刊名称：JOURNAL OF VIROLOGY
期刊影响因子：4.501
出版年份：2021
出版刊次：11
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