Dawe Harriet, Berger Evelin, Sihlbom Carina, Angus Elizabeth M, Howlin Robert P, Laver Jay R, Tebruegge Marc, Hall-Stoodley Luanne, Stoodley Paul, Faust Saul N, Allan Raymond N
Clinical and Experimental Sciences, Faculty of Medicine and Institute for Life Sciences, University of Southampton, Southampton, UK.
Proteomics Core Facility, University of Gothenburg, Gothenburg, Sweden.
Microbiology (Reading). 2017 Jul;163(7):1093-1104. doi: 10.1099/mic.0.000491. Epub 2017 Jul 21.
Non-typeable Haemophilus influenzae (NTHi) is an opportunistic pathogen that plays a major role in a number of respiratory tract infections, including otitis media, cystic fibrosis and chronic obstructive pulmonary disease. Biofilm formation has been implicated in both NTHi colonization and disease, and is responsible for the increased tolerance of this pathogen towards antibiotic treatment. Targeting metabolic pathways that are important in NTHi biofilm formation represents a potential strategy to combat this antibiotic recalcitrance. A previous investigation demonstrated increased expression of a putative d-methionine uptake protein following exposure of NTHi biofilms to the ubiquitous signalling molecule, nitric oxide. We therefore hypothesized that treatment with exogenous d-methionine would impact on NTHi biofilm formation and increase antibiotic sensitivity. Treatment of NTHi during the process of biofilm formation resulted in a reduction in biofilm viability, increased biomass, changes in the overall biofilm architecture and the adoption of an amorphous cellular morphology. Quantitative proteomic analyses identified 124 proteins that were differentially expressed following d-methionine treatment, of which 51 (41 %) were involved in metabolic and transport processes. Nine proteins involved in peptidoglycan synthesis and cell division showed significantly increased expression. Furthermore, d-methionine treatment augmented the efficacy of azithromycin treatment and highlighted the potential of d-methionine as an adjunctive therapeutic approach for NTHi biofilm-associated infections.
不可分型流感嗜血杆菌（NTHi）是一种机会致病菌，在包括中耳炎、囊性纤维化和慢性阻塞性肺疾病在内的多种呼吸道感染中起主要作用。生物膜形成与NTHi定植和疾病均有关联，并且是该病原体对抗生素治疗耐受性增加的原因。针对在NTHi生物膜形成中起重要作用的代谢途径是对抗这种抗生素耐药性的一种潜在策略。先前的一项研究表明，将NTHi生物膜暴露于普遍存在的信号分子一氧化氮后，一种假定的d-甲硫氨酸摄取蛋白的表达增加。因此，我们假设用外源性d-甲硫氨酸进行治疗会影响NTHi生物膜的形成并提高抗生素敏感性。在生物膜形成过程中对NTHi进行治疗导致生物膜活力降低、生物量增加、整体生物膜结构发生变化以及呈现无定形细胞形态。定量蛋白质组学分析确定了124种在d-甲硫氨酸处理后差异表达的蛋白质，其中51种（41%）参与代谢和转运过程。九种参与肽聚糖合成和细胞分裂的蛋白质表达显著增加。此外，d-甲硫氨酸治疗增强了阿奇霉素治疗的疗效，并突出了d-甲硫氨酸作为NTHi生物膜相关感染辅助治疗方法的潜力。
