EVALUATION OF ANTIBACTERIAL ACTIVITY OF SENNA ALATA (L.ROXB.) LEAVES AGAINST BACTERIA ASSOCIATED WITH HUMAN SKIN INFECTION

Abstract

The increasing prevalence of antimicrobial resistance has reduced the effectiveness of conventional antibiotics, creating a need for continuous surveillance and the exploration of alternative therapeutic agents. This study aimed to determine the prevalence and characteristics of bacterial pathogens associated with skin infections, evaluate their antibiotic resistance patterns and assess the antibacterial potential of the plant extracts (Senna alata) as possible alternative treatments. A cross-sectional study was conducted involving forty (40) patients with clinically diagnosed skin infections. Demographic data were obtained, and swab samples were collected for bacteriological analysis. Isolates were identified using standard biochemical tests, hemolysis assays, antibiotic susceptibility testing, and multiple antibiotic resistance (MAR) index determination. Molecular confirmation was performed using 16S rRNA gene sequencing. Leaves of S. alata were extracted using aqueous, ethanol, and acetone solvents. Antibacterial activity was evaluated using agar diffusion, minimum inhibitory concentration (MIC), and minimum bactericidal concentration (MBC) assays. Predominantly Gram-positive cocci, including Staphylococcus aureus (40.0%), Streptococcus pyogenes (36.66%), and Staphylococcus epidermidis (23.33%). Hemolysis testing showed 25.0% hemolytic strains. Antibiotic assay indicated complete sensitivity to rifampicin, ciprofloxacin, and levofloxacin, but high resistance to cefuroxime and ceftazidime. Multiple Antibiotic Resistance (MAR) indices ranged from 0.00 to 0.90, with most isolates exhibiting values ≥ 0.2, indicating exposure to high-risk antibiotic environments. Multidrug resistance was observed in 40.0% of the isolates, while several strains were extensively drug-resistant. These extracts demonstrated strong, concentration-dependent antibacterial activity, with inhibition zones up to 25 mm and MIC/MBC values ranging from 20–60 mg/mL, whereas aqueous extracts showed weaker effects. In conclusion, Gram-positive cocci, particularly S. aureus and S. pyogenes, are major etiological agents of skin infections. Organic solvent extracts of S. alata demonstrated promising antibacterial activity, suggesting their potential as alternative or adjunct therapeutic agents. Continuous antimicrobial surveillance and further pharmacological studies on plant-derived compounds are recommended to combat resistant skin pathogens.