| Congresso Brasileiro de Microbiologia 2023 | Resumo: 606-1 | ||||
Resumo:Infections caused by Klebsiella pneumoniae multidrug-resistant (MDR) strains are related to prolonged hospitalization, higher risk of mortality and increased treatment costs, representing a global challenge for public health services. Moreover, biofilm formation by K. pneumoniae increases antimicrobial tolerance and cell viability on cell surfaces, catheters, and other medical devices, also contributing to invasive infections. Data from our group and collaborators suggest that Ag-phendione and Cu-phendione, metallic compounds derived from 1,10-phenanthroline, present antimicrobial and antibiofilm activity against gram-negative bacilli. Therefore, this study
evaluated the antibiofilm activity of Ag-phendione and Cu-phendione against K. pneumoniae MDR strains: NCTC 13438 (KPC-3), NCTC 13440 (VIM-1), NCTC 13442 (OXA-48), NCTC 13368 (SHV-18) and a polymyxin-resistant KPC-producing clinical strain (8HJFA3). Biofilm formation was evaluated by an assay based on crystal violet staining in a polystyrene microplate and spectrophotometry. To further investigate the action of the metallic compounds,
liquid nanochromatography coupled to mass spectrometry (nanoESI-LC MS/MS) was used to evaluate the proteins and cellular pathways modulated by Ag-phendione and Cu-phendione in K. pneumoniae MDR strains. Ag-Fendione (0.5 MIC) and Cu-Fendione (0.5 MIC) reduced biofilm formation by 35.35% (p = 0.0307) and 30.25% (p = 0.0020), respectively. Using an Acquity UPLC M-Class nanochromatographic system coupled to a Synapt G2-Si spectrometer (Waters), 606 proteins with at least one unique peptide were identified using the UniProt database available for K. pneumoniae (5,127 proteins). Among these, 23 proteins were modulated by Ag-phendione and 17 by Cu-phenione. The enzyme trehalose-6-phosphate hydrolase (TPH), responsible for trehalose catabolism, was down-regulated by both metallic compounds. Proper utilization of trehalose and its catabolism into glucose and glucose-6-phosphate is necessary for capsule formation, also contributing to biofilm formation and colonization of the gastrointestinal tract. In K. pneumoniae, the expression of the treB and treC genes, involved in trehalose uptake and hydrolysis, respectively, is induced during the initial stages of biofilm formation, and the absence of any of these genes impairs biofilm development. Moreover, the phosphoenolpyruvate-protein phosphotransferase, down-regulated by Cu-phendione, is an enzyme that composes the phosphoenolpyruvate (PEP) carbohydrate phosphotransferase (PTS) system. Components of the PTS system positively regulate biofilm formation in K. pneumoniae through control of extracellular DNA and capsule polysaccharide production. Therefore, we suggest that the modulation of TPH and
phosphoenolpyruvate-protein phosphotransferase may be related to the antibiofilm activity of Ag-phendione and Cu-phendione against K. pneumoniae MDR strains.
Palavras-chave: Ag-phendione, antimicrobial activity, biofilm, Cu-phendione, K. pneumoniae MDR Agência de fomento:Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) e Fundação de Amparo à Pesquisa e Inovação do Espírito Santo (FAPES) | |||||