Bactericidal activity of Ag4V2O7/beta-AgVO3 heterostructures against antibiotic-resistant Klebsiella pneumoniae

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Assis, Marcelo ; da Silva, Jussara Soares ; Goncalves, Mariana Ottaiano ; de Almeida Rodolpho, Joice Margareth ; de Lima Fragelli, Bruna Dias ; Pereira Corte, Ana Beatriz ; Kelly Ribeiro, Lara ; Teodoro, Marcio Daldin ; Anibal, Fernanda de Freitas ; de Sousa, Cristina Paiva ; Oliveira Jr, Osvaldo N. ; Andres, Juan ; Longo, Elson

• Document type: Journal article
• Source: BIOMATERIALS ADVANCES; v. 141, p. 12-pg., 2022-09-05.

Abstract

Although Ag-based materials are efficient against antibiotic-resistant bacteria, their high toxicity to living organisms represents a major challenge for obtaining useful products. In this work, we report the bactericidal activity of Ag4V2O7/beta-AgVO3 heterostructures, which proved to be effective against Klebsiella pneumoniae (ATCC 1706, a standard strain; A54970, a multidrug-resistant carbapenemase (KPC)-producing strain; A34057, a multidrug-resistant strain capable of producing extended spectrum beta-lactamases (ESBL); and a community-isolated strain, A58240) at minimum inhibitory concentrations (MIC) as low as 62.5 mu g/mL. This activity is higher than that reported for the individual silver vanadates (Ag4V2O7 or beta-AgVO3) owing to the synergistic interactions between both semiconductors. However, the most efficient heterostructure was found to be toxic to mouse 3 T3 fibroblasts and to L. sativa and C. sativus seeds, as indicated by MTT ((4,5 - dimethylthiazol -2yl) 2,5 -diphenylbromide), neutral red assays and germination index measurements. The antimicrobial, phytotoxic and cytotoxic activities were all associated with an efficient generation of reactive oxygen species (ROS) in the heterostructure, especially (OH)-O-center dot and O-center dot(2) radicals. The ROS production by Ag4V2O7/beta-AgVO3 heterostructures was measured through photodegradation studies with Rhodamine B. While the bactericidal activity of the heterostructures is promising, especially when compared to Ag-based materials, their use in practical applications will require encapsulation either to avoid leaching or to mitigate their toxicity to humans, animals and plants. (AU)

• FAPESP's process: 13/07296-2 - CDMF - Center for the Development of Functional Materials
• Grantee: Elson Longo da Silva
• Support Opportunities: Research Grants - Research, Innovation and Dissemination Centers - RIDC
• FAPESP's process: 16/13423-5 - Compounds produced by endophyte microorganisms isolated from Brazilian tropical savannah: bioactivity, association with a-Ag2WO4 and biotechnological applications
• Grantee: Cristina Paiva de Sousa
• Support Opportunities: Regular Research Grants
• FAPESP's process: 18/22214-6 - Towards a convergence of technologies: from sensing and biosensing to information visualization and machine learning for data analysis in clinical diagnosis
• Grantee: Osvaldo Novais de Oliveira Junior
• Support Opportunities: Research Projects - Thematic Grants