Antibacterial activity of some medicinal plants and antibiotics against Staphylococcus aureus and Mammaliicoccus sciuri isolated from acne

Background: Acne vulgaris is a distressing condition that affects most adolescents, causing scarring and reducing the quality of life. Among all the available therapeutic options, antibiotics are routinely used to treat moderate acne. In some cases, the clinical symptoms temporarily disappear after applying the prescribed medications, but its reoccurrence along with the misuse and overuse of the prescribed antibiotics may result in the emergence of multidrug-resistant strains. Methods: The present study aims to isolate and identify acne-causing bacteria from two individuals, who developed chronic or recurrent papules or pustules on their face and neck. The effect of different physiological factors on the growth of these bacteria was evaluated, followed by an evaluation of microbial adhesion, biofilm formation, hemolytic activity, extracellular enzyme production, and antibacterial activity of some medicinal plants and antibiotics. Results: The predominant bacteria in acne samples were Gram-positive cocci, which were identified as Staphylococcus aureus strain GCC20_MS and Mammaliicoccus sciuri strain GCC20_MS. Both the isolates showed maximum viability at pH 7.0 and significant growth up to 10% NaCl concentration. A decreased viable count with the increase in Lysozyme concentration was also observed. The cell-surface hydrophobicity and auto-aggregation of both the tested isolates were very low; however, the strains were moderate biofilm producers. S. aureus strain GCC_20MS exhibited β-hemolysis, whereas M. sciuri strain GCC_20RS showed γ-hemolytic activity (no-hemolysis). Antibiotic-sensitivity test showed resistance of both the strains toward penicillin and sensitivity toward tetracycline, chloramphenicol, ciprofloxacin, levofloxacin, co-Trimoxazole, gentamicin, and ofloxacin. The aqueous extracts of Citrus limon and Psidium guajava significantly inhibit the growth of the isolated strains. Moderate growth inhibition was observed by the aqueous extracts of Mentha sachalinensis and Punica granatum. Conclusion: The study suggests the efficacy of topical anti-acne formulations using plant extracts that may target the early processes of acne development and combat the emergence of multidrug-resistant strains.