Utilization of Limosilactobacillus fermentum Cells in a Gel Formula as a Dermal Probiotic against MDR Pseudomonas aeruginosa Associated with Burn Wound Infection

Abstract

This work aimed to select a safe and bacteriocin-producing isolate of Lactobacillus to use it as a probiotic for treating Pseudomonas aeruginosa associated with burn infections. For this purpose, 151 burn wound swabs were collected from patients to isolate the most common multi-drug resistance Pseudomonas aeruginosa that could be used as an indicator. In addition, thirty-six Lactobacillus isolates were collected from different sources and subjected to a screening program to evaluate their antagonism activities against MDR P. aeruginosa. Based on results, the isolate Lactobacillus HLB12 showed a highest bacteriocin production which was further characterized as Limosilactobacillus fermentum through 16s ribosomal RNA. Several tests were performed to study the properties of Limosilactobacillus fermentum HLB12, particularly its biosafety and suitability to be a successful probiotic. Results showed that L. fermentum HLB12 was resistant to β-lactams group such as ticarcillin/clavulanate. Whereas it was sensitive to amikacin, ciprofloxacin and levofloxacin. Moreover, the results confirmed that L. fermentum HLB12 was safe as a probiotic without any health impacts as it has no hemolytic activity. Furthermore, results revealed that this bacterium was strongly adherent and good biofilm producer, had high auto-aggregation capability and high ability of adhering with Pseudomonas aeruginosa. Limosilactobacillus fermentum cells were successfully incorporated into a gel base formula. The results revealed that cells kept their viability over 21 days with an ability to produce and release the bacteriocin. The formula was tested in vitro and results showed a high antagonistic activity against Pseudomonas aeruginosa. Next, the formula was tested in vivo to treat rabbit models with full-thickness skin burn. Upon examining the healing process, results showed signs of remodeling stage by day four and scar tissue formation by day nine. The results supported the idea of using probiotic as an alternative method for the treatment with antibiotics.