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Methicillin-resistant Staphylococcus aureus (MRSA) mastitis poses a significant threat to dairy herds worldwide, given its resistance to methicillin and other b-lactam antibiotics, which often leads to treatment failure. Consequently, there is an urgent need for safe and effective alternative therapeutic approaches. Recent investigations have highlighted the potential of baicalein, a natural flavonoid known for its potent anti-inflammatory and antibacterial properties, especially its synergistic effects with b-lactam antibiotics against MRSA. However, the limited solubility and bioavailability of baicalein hinder its biomedical utility. The present study assessed the therapeutic efficacy of encapsulated baicalein in chitosan, forming a tricomplex with a b-lactam antibiotic, using a murine model of MRSA-induced mastitis. The experimental design comprised seven groups, each consisting of six mice. We evaluated the ability of various treatment regimens to mitigate histopathological alterations and bacterial burden induced by MRSA infection, aiming to elucidate underlying mechanisms. Our results revealed that tricomplex treatment significantly reduced bacterial load in mammary tissue and preserved tissue integrity, resulting in decreased inflammatory responses post-MRSA inoculation. In addition, tricomplex treatment markedly reduced mean leukocyte and neutrophil counts in blood and suppressed the matrix metalloproteinase-9 (MMP-9) concentration and C-reactive protein (CRP) response. Notably, the synergistic interaction between baicalein and amoxicillin was particularly pronounced. Our findings suggest that chitosan-encapsulated baicalein combined with a b-lactam antibiotic holds promise as a therapeutic option for MRSA-induced mastitis. Further investigations, particularly in target animal species, are warranted to comprehensively evaluate its clinical feasibility. [ABSTRACT FROM AUTHOR]

The pressing issue of the moment affecting public health is antimicrobial resistance. Methicillin-resistant Staphylococcus aureus (MRSA) is an emerging pathogen that is proven to be resistant to a range of antibiotics like penicillins, cephalosporins, other b-lactam antibiotics, and carbapenems. Baicalein, a phytochemical of the traditional Chinese herb, Scutellaria baicalensis has an inhibitory effect on different bacteria. The current study aimed to investigate the synergistic effect of baicalein and b-lactam antibiotics (amoxicillin and ampicillin) against methicillin-resistant S. aureus (MRSA). The minimum inhibitory concentrations (MICs) of baicalein and b-lactam antibiotics (amoxicillin and ampicillin) against the MRSA were determined through the broth dilution method. The determination of synergism was tested by checkerboard tube dilution and time-kill assay procedure. The combination of baicalein with amoxicillin showed more potent synergy against MRSA strain compared to the combination of baicalein and ampicillin. The fractional inhibitory concentration indices (FICI) of amoxicillin + baicalein varied from 0.19 to 0.50. The fractional inhibitory concentration (FIC) indices of ampicillin + baicalein varied from 0.19 to 0.25. These findings offer significant evidence that the amoxicillin combined with baicalein showed potent synergistic activity against MRSA in vitro and might offer promising therapeutic implications for MRSA infections. [ABSTRACT FROM AUTHOR]