Department of Pathology, Beth Israel Deaconess Medical Center, Boston, Massachusetts, USA.
Harvard Medical School, Boston, Massachusetts, USA.
mSphere. 2023 Apr 20;8(2):e0067322. doi: 10.1128/msphere.00673-22. Epub 2023 Feb 28.
Pathogen inactivation is a strategy to improve the safety of transfusion products. The only pathogen reduction technology for blood products currently approved in the US utilizes a psoralen compound, called amotosalen, in combination with UVA light to inactivate bacteria, viruses, and protozoa. Psoralens have structural similarity to bacterial multidrug efflux pump substrates. As these efflux pumps are often overexpressed in multidrug-resistant pathogens, we tested whether contemporary drug-resistant pathogens might show resistance to amotosalen and other psoralens based on multidrug efflux mechanisms through genetic, biophysical, and molecular modeling analysis. The main efflux systems in , Acinetobacter baumannii, and Pseudomonas aeruginosa are tripartite resistance-nodulation-cell division (RND) systems, which span the inner and outer membranes of Gram-negative pathogens, and expel antibiotics from the bacterial cytoplasm into the extracellular space. We provide evidence that amotosalen is an efflux substrate for the E. coli AcrAB, Acinetobacter baumannii AdeABC, and P. aeruginosa MexXY RND efflux pumps. Furthermore, we show that the MICs for contemporary Gram-negative bacterial isolates for these species and others approached and exceeded the concentration of amotosalen used in the approved platelet and plasma inactivation procedures. These findings suggest that otherwise safe and effective inactivation methods should be further studied to identify possible gaps in their ability to inactivate contemporary, multidrug-resistant bacterial pathogens. Pathogen inactivation is a strategy to enhance the safety of transfused blood products. We identify the compound, amotosalen, widely used for pathogen inactivation, as a bacterial multidrug efflux substrate. Specifically, experiments suggest that amotosalen is pumped out of bacteria by major efflux pumps in E. coli, Acinetobacter baumannii, and Pseudomonas aeruginosa. Such efflux pumps are often overexpressed in multidrug-resistant pathogens. Importantly, the MICs for contemporary multidrug-resistant , Acinetobacter baumannii, Pseudomonas aeruginosa, spp., and Stenotrophomonas maltophilia isolates approached or exceeded the amotosalen concentration used in approved platelet and plasma inactivation procedures, potentially as a result of efflux pump activity. Although there are important differences in methodology between our experiments and blood product pathogen inactivation, these findings suggest that otherwise safe and effective inactivation methods should be further studied to identify possible gaps in their ability to inactivate contemporary, multidrug-resistant bacterial pathogens.
病原体灭活是提高输血产品安全性的一种策略。目前在美国获得批准的唯一用于血液制品的病原体减少技术是利用一种称为氨甲蝶呤的补骨脂素化合物，与 UVA 光结合来灭活细菌、病毒和原生动物。补骨脂素与细菌多药外排泵底物具有结构相似性。由于这些外排泵在多药耐药病原体中常常过度表达，我们通过遗传、生物物理和分子建模分析，测试了当代耐药病原体是否可能基于多药外排机制对氨甲蝶呤和其他补骨脂素表现出耐药性。在 、鲍曼不动杆菌和铜绿假单胞菌中，主要的外排系统是三部分耐药性-结节性-细胞分裂（RND）系统，该系统跨越革兰氏阴性病原体的内外膜，并将抗生素从细菌细胞质中排出到细胞外空间。我们提供的证据表明，氨甲蝶呤是大肠杆菌 AcrAB、鲍曼不动杆菌 AdeABC 和铜绿假单胞菌 MexXY RND 外排泵的外排底物。此外，我们还表明，这些物种和其他物种的当代革兰氏阴性细菌分离株的 MIC 值接近并超过了用于批准的血小板和血浆灭活程序的氨甲蝶呤浓度。这些发现表明，否则安全有效的灭活方法应进一步研究，以确定其灭活当代多药耐药细菌病原体的能力可能存在差距。病原体灭活是增强输血血液产品安全性的一种策略。我们确定了广泛用于病原体灭活的化合物氨甲蝶呤是一种细菌多药外排泵底物。具体来说，实验表明，氨甲蝶呤被大肠杆菌、鲍曼不动杆菌和铜绿假单胞菌中的主要外排泵泵出细菌。这种外排泵在多药耐药病原体中常常过度表达。重要的是，当代多药耐药 、鲍曼不动杆菌、铜绿假单胞菌、 spp.和嗜麦芽窄食单胞菌分离株的 MIC 值接近或超过了批准的血小板和血浆灭活程序中使用的氨甲蝶呤浓度，这可能是由于外排泵活性所致。尽管我们的实验与血液制品病原体灭活在方法上存在重要差异，但这些发现表明，否则安全有效的灭活方法应进一步研究，以确定其灭活当代多药耐药细菌病原体的能力可能存在差距。
