Antimicrobial activities of graphene oxide against biofilm and intracellular Staphylococcus aureus isolated from bovine mastitis

Abstract

Background S. aureus is one of the causative agents of bovine mastitis. The treatment using conventional antimicrobials has been hampered due to the development of antimicrobial resistance and the ability of the bacteria to form biofilms and localize inside the host cells. Objectives Here, the efficacy of graphene oxide (GO), a carbon-based nanomaterial, was tested against the biofilms and intracellular S. aureus invitro. Following that, the mechanism for the intracellular antimicrobial activities and GO toxicities was elucidated. Methods GO antibiofilm properties were evaluated based on the disruption of biofilm structure, and the intracellular antimicrobial activities were determined by the survival of S. aureus in infected bovine mammary cells following GO exposure. The mechanism for GO intracellular antimicrobial activities was investigated using endocytosis inhibitors. GO toxicity towards the host cells was assessed using a resazurin assay. Results At 100 ug/mL, GO reduced between 30 and 70% of S. aureus biofilm mass, suggesting GO’s ability to disrupt the biofilm structure. At 200 ug/mL, GO killed almost 80% of intracellular S. aureus, and the antimicrobial activities were inhibited when cells were pre-treated with cytochalasin D, suggesting GO intracellular antimicrobial activities were dependent on the actin-polymerization of the cell membrane. At < 250 ug/mL, GO enhanced the viability of the Mac-T cell, and cells were only affected at higher dosages. Conclusion The in vitro efficacy of GO against S. aureus in vitro suggested the compound could be further tested in Vivo to zrecognize its potential as one of the components of bovine mastitis therapy.

Confronting the complexities of antimicrobial management for Staphylococcus aureus causing bovine mastitis: an innovative paradigm

“…Also, GO at 100 μg/mL reduced between 30–70% of S. aureus biofilm mass, suggesting GO ability to disrupt the biofilm structure. the toxicity was recorded at a concentration higher than 1000 μg/mL, which is higher than the concentration needed to inhibited the bacteria growth [ 103 ]. Despite the antimicrobial properties of Graphene – based materials several other studies measured GO toxicity towards the following cell line, human breast cancer, ovarian cancer, HeLa and mouse embryonic fibroblast.…”

“…Despite the antimicrobial properties of Graphene – based materials several other studies measured GO toxicity towards the following cell line, human breast cancer, ovarian cancer, HeLa and mouse embryonic fibroblast. Briefly, GO toxicity level varied and highly dependent on time of exposure and dose of the compound [ 102 , 103 ]. On the other hand, the recent by Saeed et al showed that Mac-T cells appeared to have tolerance to GO with cell viability were only affected when cells were exposed to GO at concentration higher than required concentration to kills bacteria [ 103 ].…”

“…Briefly, GO toxicity level varied and highly dependent on time of exposure and dose of the compound [ 102 , 103 ]. On the other hand, the recent by Saeed et al showed that Mac-T cells appeared to have tolerance to GO with cell viability were only affected when cells were exposed to GO at concentration higher than required concentration to kills bacteria [ 103 ]. Suggesting that this compound has lower toxicity levels and its can be a good potential alternative antimicrobial for treatment of mastitis.…”

SMR peptide antagonizes Staphylococcus aureus biofilm formation

“…Mortalin also interacts with proteins, such as Nef, to elicit the secretion of extracellular vesicles (EV) that mediate intercellular communication and environmental response coordination. Both antibody inhibition and miRNA knockdown experiments confirmed that blocking mortalin blocks Nef-EV secretion in Nef-transfected cells, as well as disrupts mortalin/Nef interactions occurring through the SMR domain ( 28 ). Our recent research demonstrated that SMR peptide treatment in breast cancer cells blocked EV secretion, induced cell cycle arrest at the G2/M phase, and reduced cellular proliferation ( 40 , 41 ).…”

“…In our previous studies, we have found multiple novel effects of the SMR peptides through targeting mortalin in HIV/AIDS and breast cancer ( 28 ). Similar to DnaK, mortalin is involved in the translocation and folding of proteins to regulate many processes, including cell growth, apoptosis, and autophagy.…”