Amer Mai A, Wasfi Reham, Hamed Samira M
Department of Microbiology and Immunology, Faculty of Pharmacy, October University for Modern Sciences and Arts (MSA), Giza, Egypt.
Front Cell Infect Microbiol. 2023 Jul 13;13:1210195. doi: 10.3389/fcimb.2023.1210195. eCollection 2023.
is a leading cause of biofilm-associated infections, particularly catheter-related bloodstream infections (CRBSIs) that are mostly recalcitrant to antimicrobial therapy. One approach to reducing the burden of CRBSIs is inhibiting biofilm formation on catheters. Owing to their prodigious microbial diversity, bacterial endophytes might be a valuable source of biosurfactants, which are known for their great capacity to disperse microbial biofilms. With this in mind, our study aimed to screen bacterial endophytes from plants growing on the banks of the River Nile for the production of powerful biosurfactants capable of reducing the ability of to form biofilms on central venous catheters (CVCs). This was tested on multidrug- and extensive drug-resistant (M/XDR) clinical isolates of that belong to high-risk global clones and on a standard strain of ATCC 19606. The drop collapse and oil dispersion assays were employed in screening the cell-free supernatants (CFS) of all endophytes for biosurfactant activity. Of the 44 bacterial endophytes recovered from 10 plants, the CFS of Cp24, isolated from , showed the highest biosurfactant activity. The crude biosurfactant extract of Cp24 showed potent antibacterial activity with minimum inhibitory concentrations (MICs) ranging from 0.78 to 1.56 mg/ml. It also showed significant antibiofilm activity (p-value<0.01). Sub-MICs of the extract could reduce biofilm formation by up to 89.59%, while up to 87.3% of the preformed biofilms were eradicated by the MIC. A significant reduction in biofilm formation on CVCs impregnated with sub-MIC of the extract was demonstrated by CV assay and further confirmed by scanning electron microscopy. This was associated with three log reductions in adhered bacteria in the viable count assay. GC-MS analysis of the crude biosurfactant extract revealed the presence of several compounds, such as saturated, unsaturated, and epoxy fatty acids, cyclopeptides, and 3-Benzyl-hexahydro-pyrrolo [1, 2-a] pyrazine-1,4-dione, potentially implicated in the potent biosurfactant and antibiofilm activities. In the present study, we report the isolation of a endophyte from the plant that produces a biosurfactant with potent antibiofilm activity against MDR/XDR global clones of . The impregnation of CVCs with the biosurfactant was demonstrated to reduce biofilms and, hence, proposed as a potential strategy for reducing CRBSIs.
是生物膜相关感染的主要原因,尤其是导管相关血流感染(CRBSIs),这类感染大多对抗菌治疗具有顽固性。减轻CRBSIs负担的一种方法是抑制导管上生物膜的形成。由于其巨大的微生物多样性,细菌内生菌可能是生物表面活性剂的宝贵来源,生物表面活性剂以其分散微生物生物膜的强大能力而闻名。考虑到这一点,我们的研究旨在从尼罗河岸生长的植物中筛选细菌内生菌,以生产能够降低在中心静脉导管(CVCs)上形成生物膜能力的强效生物表面活性剂。这在属于全球高风险克隆的多药耐药和广泛耐药(M/XDR)临床分离株以及标准菌株ATCC 19606上进行了测试。采用液滴塌陷和油分散试验筛选所有内生菌的无细胞上清液(CFS)的生物表面活性剂活性。从10种植物中分离出的44株细菌内生菌中,从[具体植物名称未给出]分离出的Cp24的CFS表现出最高的生物表面活性剂活性。Cp24的粗生物表面活性剂提取物显示出强大的抗菌活性,最低抑菌浓度(MICs)范围为0.78至1.56mg/ml。它还表现出显著的抗生物膜活性(p值<0.01)。提取物的亚MICs可将生物膜形成减少高达89.59%,而MIC可根除高达87.3%的预先形成的生物膜。通过CV测定证明,用提取物的亚MIC浸渍CVCs可显著减少生物膜形成,并通过扫描电子显微镜进一步证实。这与活菌计数试验中附着细菌减少三个对数有关。粗生物表面活性剂提取物的GC-MS分析揭示了几种化合物的存在,如饱和、不饱和和环氧脂肪酸、环肽以及3-苄基-六氢-吡咯并[1,2-a]吡嗪-1,4-二酮,这些化合物可能与强效生物表面活性剂和抗生物膜活性有关。在本研究中,我们报告了从[具体植物名称未给出]植物中分离出一种内生菌,该内生菌产生一种对MDR/XDR全球克隆具有强效抗生物膜活性的生物表面活性剂。证明用生物表面活性剂浸渍CVCs可减少生物膜,因此,提出这是减少CRBSIs的一种潜在策略。