RESUMO
Mastitis is one the most widespread and serious diseases in dairy cattle. Recurrent and chronic infections are often attributable to certain pathogenicity mechanisms in mastitis-causing pathogens such as Staphylococcus spp. These include growing in biofilm and invading cells, both of which make it possible to resist or evade antimicrobial therapies and the host's immune system. This study tested the effects of active vitamin D3 (i.e., calcitriol or 1,25-dihydroxyvitamin D3) on the internalization and phagocytosis of biofilm-forming Staphylococcus spp. isolated from animals with mastitis. Two established bovine cell lines were used: MAC-T (mammary epithelial cells) and BoMac (macrophages). Calcitriol (0-200â¯nM) did not affect the viability of MAC-T cells nor that of BoMac cells after 24 and 72â¯h. Concentrations of 0-100â¯mM for 24â¯h upregulated the expression of 24-hydroxylase in MAC-T cells, but did not alter that of VDR. Pre-treatment of the cells with calcitriol for 24â¯h decreased the internalization of S. aureus V329 into MAC-T cells (0-100â¯nM), and stimulated the phagocytosis of the same strain and of S. xylosus 4913 (0-10â¯nM). Calcitriol and two conditioned media, obtained by treating the cells with 25-200â¯nM of the metabolite for 24â¯h, were also assessed in terms of their antimicrobial and antibiofilm activity. Neither calcitriol by itself nor the conditioned media affected staphylococcal growth or biofilm formation (0-200â¯nM for 12 and 24â¯h, respectively). In contrast, the conditioned media (0-100â¯nM for 24â¯h) decreased the biomass of preformed non-aureus staphylococcal biofilms and killed the bacteria within them, without affecting metabolic activity. These effects may be mediated by reactive oxygen species and proteins with antimicrobial and/or antibiofilm activity. In short, calcitriol could make pathogens more accessible to antimicrobial therapies and enhance bacterial clearance by professional phagocytes. Moreover, it may modulate the host's endogenous defenses in the bovine udder and help combat preformed non-aureus staphylococcal biofilms (S. chromogenes 40, S. xylosus 4913, and/or S. haemolyticus 6). The findings confirm calcitriol's potential as an adjuvant to prevent and/or treat intramammary infections caused by Staphylococcus spp., which would in turn contribute to reducing antibiotic use on dairy farms.
Assuntos
Biofilmes , Imunidade Inata , Mastite Bovina , Fagocitose , Staphylococcus , Animais , Bovinos , Biofilmes/efeitos dos fármacos , Biofilmes/crescimento & desenvolvimento , Feminino , Mastite Bovina/microbiologia , Mastite Bovina/imunologia , Imunidade Inata/efeitos dos fármacos , Staphylococcus/efeitos dos fármacos , Fagocitose/efeitos dos fármacos , Calcitriol/farmacologia , Infecções Estafilocócicas/microbiologia , Infecções Estafilocócicas/veterinária , Infecções Estafilocócicas/imunologia , Infecções Estafilocócicas/tratamento farmacológico , Linhagem Celular , Glândulas Mamárias Animais/microbiologia , Glândulas Mamárias Animais/imunologia , Macrófagos/microbiologia , Macrófagos/efeitos dos fármacos , Macrófagos/imunologia , Macrófagos/metabolismoRESUMO
The bacterial resistance to antibiotics has compromised the therapies used for bacterial infections. Nowadays, many strategies are being carried out to address this problem. Among them, the use of natural compounds like cinnamic and p-coumaric acids stands out. Nevertheless, their utilization is limited because of their unfavorable physicochemical properties. Due to the lack of new therapeutic alternatives for bacterial infections, novel strategies have emerged, such as the use of ionic liquids; given that they can show a broad spectrum of antibacterial activity, this is why we herein report the antibacterial and antibiofilm activity of a series of N-alkylimidazolium salts functionalized with p-coumaric and cinnamic acids. The results from this study showed better antibacterial activity against Gram-positive bacteria, with a predominance of the salts derived from coumaric acid and a correlation with the chain length. Additionally, a lower efficacy was observed in the inhibition of biofilm formation, highlighting the antibiofilm activity against Staphylococcus aureus, which decreased the production of the biofilm by 52% over the control. In conclusion, we suggest that the salts derived from p-coumaric acid are good alternatives as antibacterial compounds. Meanwhile, the salt derived from cinnamic acid could be a good alternative as an antibiofilm compound.