Zinc effects on bacteria: insights from Escherichia coli by multi-omics approach.

IMPORTANCE: A long-term exposure of bacteria to zinc oxide and zinc oxide nanoparticles leads to major alterations in bacterial morphology and physiology. These included biochemical and physiological processes promoting the emergence of strains with multi-drug resistance and virulence traits. After the removal of zinc pressure, bacterial phenotype reversed back to the original state; however, certain changes at the genomic, transcriptomic, and proteomic level remained. Why is this important? The extensive and intensive use of supplements in animal feed effects the intestinal microbiota of livestock and this may negatively impact the health of animals and people. Therefore, it is crucial to understand and monitor the impact of feed supplements on intestinal microorganisms in order to adequately assess and prevent potential health risks.

Synergistic antibacterial action of the iron complex and ampicillin against Staphylococcus aureus.

OBJECTIVES: Resistance to antibiotics among bacteria of clinical importance, including Staphylococcus aureus, is a serious problem worldwide and the search for alternatives is needed. Some metal complexes have antibacterial properties and when combined with antibiotics, they may increase bacterial sensitivity to antimicrobials. In this study, we synthesized the iron complex and tested it in combination with ampicillin (Fe16 + AMP) against S. aureus. METHODS: An iron complex (Fe16) was synthesized and characterized using spectroscopy methods. Confirmation of the synergistic effect between the iron complex (Fe16) and ampicillin (AMP) was performed using ζ-potential, infrared spectra and FICI index calculated from the minimum inhibitory concentration (MIC) from the checkerboard assay. Cytotoxic properties of combination Fe16 + AMP was evaluated on eukaryotic cell line. Impact of combination Fe16 + AMP on chosen genes of S. aureus were performed by Quantitative Real-Time PCR. RESULTS: The MIC of Fe16 + AMP was significantly lower than that of AMP and Fe16 alone. Furthermore, the infrared spectroscopy revealed the change in the ζ-potential of Fe16 + AMP. We demonstrated the ability of Fe16 + AMP to disrupt the bacterial membrane of S. aureus and that likely allowed for better absorption of AMP. In addition, the change in gene expression of bacterial efflux pumps at the sub-inhibitory concentration of AMP suggests an insufficient import of iron into the bacterial cell. At the same time, Fe16 + AMP did not have any cytotoxic effects on keratinocytes. CONCLUSIONS: Combined Fe16 + AMP therapy demonstrated significant synergistic and antimicrobial effects against S. aureus. This study supports the potential of combination therapy and further research.

Titanium dioxide nanoparticles: Recent progress in antimicrobial applications.

For decades, the antimicrobial applications of nanoparticles (NPs) have attracted the attention of scientists as a strategy for controlling the ever-increasing threat of multidrug-resistant microorganisms. The photo-induced antimicrobial properties of titanium dioxide (TiO2 ) NPs by ultraviolet (UV) light are well known. This review elaborates on the modern methods and antimicrobial mechanisms of TiO2 NPs and their modifications to better understand and utilize their potential in various biomedical applications. Additional compounds can be grafted onto TiO2 nanomaterial, leading to hybrid metallic or non-metallic materials. To improve the antimicrobial properties, many approaches involving TiO2 have been tested. The results of selected studies from the past few years covering the most recent trends in this field are discussed in this review. There is extensive evidence to show that TiO2 NPs can exhibit certain antimicrobial features with disputable roles of UV light. Hence, they are effective in treating bacterial infections, although the majority of these conclusions came from in vitro studies and in the presence of some additional nanomaterials. The methods of evaluation varied depending on the nature of the research while researchers incorporated different techniques, including determining the minimum inhibitory concentration, cell count, and using disk and well diffusion methods, with a noticeable indication that cell count was the most and dominant criterion used to evaluate the antimicrobial activity. This article is categorized under: Nanotechnology Approaches to Biology > Nanoscale Systems in Biology Therapeutic Approaches and Drug Discovery > Emerging Technologies Therapeutic Approaches and Drug Discovery > Nanomedicine for Infectious Disease.