In vivo antibacterial activity of Streptomyces tuirus against MRSA-infected model

Antibiotic resistance poses a global health risk, prompting researchers to focus on discovering new effective therapeutics from microbial sources. Hence, this study assessed the antimicrobial activity of the ethyl acetate crude extract of Streptomyces tuirus against MRSA in mice, providing the first in vivo validation of its previously reported in vitro activity. BALB/c mice (23 ± 1.2 g) were divided into 6 groups (6 mice/group). Groups I and II served as negative controls for saline and DMSO, respectively, while Group III received only the crude extract (10 mg/kg (post safety assessment). The crude extract was obtained using ethyl acetate extraction following submerged fermentation. Groups IV, V, and VI were intraperitoneally infected with 10⁸ CFU/ml MRSA. Subsequently, Group IV received no treatment, Group V was administered 10 mg/kg of the crude extract, and Group VI received 150 mg/kg of vancomycin. The treatment was given intraperitoneally for 7 days. At the end of the experiment, blood, liver, and kidney samples were collected. A hematological analysis was performed, followed by biochemical assessment for aspartate aminotransferase (AST), alanine aminotransferase (ALT), C-reactive protein (C-RP), and creatinine, along with histopathological examinations. MRSA infection induced significant systemic alterations. Although vancomycin was effective, it remained associated with elevated AST, ALT, and creatinine. However, the crude extract improved the hematological and biochemical parameters. It decreased AST, ALT, and creatinine by 42.94% (P-value 0.001), 43.33% (P-value 0.006), and 32.79% (P-value 0.0003), respectively, compared to the untreated infected Group. The crude extract of S. tuirus demonstrated in vivo antibacterial efficacy and a favorable safety profile against MRSA in mice.