在体外、生物膜和体内对多药耐药肺炎克雷伯菌进行测试的吗啉代寡聚物。
Morpholino oligomers tested in vitro, in biofilm and in vivo against multidrug-resistant Klebsiella pneumoniae.
机构信息
Department of Microbiology, 226 Nash Hall, Oregon State University, Corvallis, OR 97331, USA.
Department of Internal Medicine, 5323 Harry Hines Blvd., University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
出版信息
J Antimicrob Chemother. 2018 Jun 1;73(6):1611-1619. doi: 10.1093/jac/dky058.
BACKGROUND
Klebsiella pneumoniae is an opportunistic pathogen and many strains are multidrug resistant. KPC is one of the most problematic resistance mechanisms, as it confers resistance to most β-lactams, including carbapenems. A promising platform technology for treating infections caused by MDR pathogens is the nucleic acid-like synthetic oligomers that silence bacterial gene expression by an antisense mechanism.
OBJECTIVES
To test a peptide-conjugated phosphorodiamidate morpholino oligomer (PPMO) in a mouse model of K. pneumoniae infection.
METHODS
PPMOs were designed to target various essential genes of K. pneumoniae and screened in vitro against a panel of diverse strains. The most potent PPMOs were further tested for their bactericidal effects in broth cultures and in established biofilms. Finally, a PPMO was used to treat mice infected with a KPC-expressing strain.
RESULTS
The most potent PPMOs targeted acpP, rpmB and ftsZ and had MIC75s of 0.5, 4 and 4 μM, respectively. AcpP PPMOs were bactericidal at 1-2 × MIC and reduced viable cells and biofilm mass in established biofilms. In a mouse pneumonia model, therapeutic intranasal treatment with ∼30 mg/kg AcpP PPMO improved survival by 89% and reduced bacterial burden in the lung by ∼3 logs. Survival was proportional to the dose of AcpP PPMO. Delaying treatment by 2, 8 or 24 h post-infection improved survival compared with control groups treated with PBS or scrambled sequence (Scr) PPMOs.
CONCLUSIONS
PPMOs have the potential to be effective therapeutic agents against KPC-expressing, MDR K. pneumoniae.
背景
肺炎克雷伯菌是一种机会性病原体，许多菌株具有多重耐药性。KPC 是最成问题的耐药机制之一，因为它使大多数β-内酰胺类药物（包括碳青霉烯类药物）产生耐药性。一种有前途的治疗多药耐药病原体感染的平台技术是核酸类似物合成寡核苷酸，它通过反义机制沉默细菌基因表达。
目的
在肺炎克雷伯菌感染的小鼠模型中测试一种肽偶联的磷酰胺二酯吗啉寡聚物（PPMO）。
方法
设计 PPMO 以针对肺炎克雷伯菌的各种必需基因，并在体外针对多种不同菌株进行筛选。最有效的 PPMO 进一步在肉汤培养物和已建立的生物膜中测试其杀菌效果。最后，使用 PPMO 治疗表达 KPC 的菌株感染的小鼠。
结果
最有效的 PPMO 靶向 acpP、rpmB 和 ftsZ，MIC75 分别为 0.5、4 和 4 μM。AcpP PPMO 在 1-2×MIC 时具有杀菌作用，并减少已建立的生物膜中的活细胞和生物膜质量。在小鼠肺炎模型中，治疗性鼻腔内给予约 30mg/kg AcpP PPMO 可使存活率提高 89%，并使肺部细菌负荷减少约 3 个对数级。存活率与 AcpP PPMO 的剂量成正比。与用 PBS 或乱序（Scr）PPMO 治疗的对照组相比，在感染后 2、8 或 24 小时延迟治疗可提高存活率。
结论
PPMO 有可能成为治疗表达 KPC、多药耐药肺炎克雷伯菌的有效治疗剂。
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