Studying the antibiotic susceptibility and antibacterial activity of probiotic bacteria against pathogenic bacteria isolated from skin infections

Background: Probiotics refer to live microorganisms that promote the organism's well-being when consumed in sufficient quantities. Lactobacillus acidophilus, a well-established probiotic, is often suggested for its positive impact on health. Objective: To investigate the spread of antibiotic resistance and the antibacterial effectiveness of probiotic bacteria against pathogenic bacteria obtained from skin infections. Methodology: A total of 40 samples were collected from patients with skin infections in August and October 2017 from two hospitals in Baghdad. The samples originated from patients of various ages and genders. Following standard morphological and biochemical characterization, 69 isolates were identified as Enterobacter cloacae (n=12, 17.4%), Klebsiella pneumoniae (n=1, 1.4%), Proteus mirabilis (n=1, 1.4%), Pseudomonas aeruginosa (n=15, 21.7%), and Staphylococcus aureus (n=21, 30.4%). Eleven isolates (15.9%) belonged to Staphylococcus epidermidis, with the remaining isolates distributed across Bacillus spp. (n=6, 8.6%), Pseudomonas stutzeri (n=1, 1.4%), and Enterobacter aerogenes (n=1, 1.4%). Antibiotic susceptibility testing using nine antibiotics identified 18 isolates resistant to Gentamicin, Cefotaxime, Amikacin, Ceftriaxone, Tobramycin, and Amoxicillin-clavulanic acid. L. acidophilus, a potential probiotic, was cultured and evaluated for its inhibitory activity against the isolated skin infection bacteria. Results: The results upon evaluating the inhibitory effect of the probiotic L. acidophilus against bacteria causing skin infections demonstrated a broad-spectrum inhibitory impact at all tested concentrations against the isolated skin infection pathogens. Conclusion: L. acidophilus, a probiotic bacterium, demonstrated inhibitory activity against skin infection-causing bacteria.