Antimicrobial resistance is increasing worldwide and is of particular concern in Gram-negative bacilli where there is a paucity of new and effective antimicrobial agents. Pseudomonas aeruginosa infections are associated with increased mortality and morbidity, especially in immunocompromised and burns patients respectively. The organism is capable of developing resistance to practically most classes of antibiotics and has always been considered a difficult target for antimicrobial chemotherapy because of the ability of bacteria to form biofilm. A biofilm is a structured consortium of bacteria, embedded in a self-produced polymer matrix consisting of polysaccharide, protein and DNA. Biofilm bacteria are a major concern in the treatment of infectious diseases. The objective of the project work is to evaluate the efficacy of the combination of antibiotics with different agents against P. aeruginosa biofilm.
In this study, among the six essential oils tested, the synergistic interaction of tetracycline with garlic essential oil showed significant inhibition against Pseudomonas aeruginosa biofilm formation compared to the other essential oils. In addition to these, we also studied combination of tetracycline with D-amino acids such as D-Leucine, D-Methionine, D-Tyrosine, and D-Tryptophan. In this, tetracycline and D-Tryptophan combination shows a significant reduction in biofilm formation of P. aeruginosa. The validation of the potential of Garlic essential oil in combination with Tetracycline in an in vitro wound dressing model and an ex vivo porcine skin model confirms the efficacy of these combinations.