Nanoemulsions: a promising strategy in the fight against bacterial infections

In recent years, bacterial infections have become a major global concern, causing significant morbidity and mortality. Unfortunately, the development and commercialization of new antibacterial drugs have been slow, while pathogens continue to rapidly adapt and evolve. To address this challenge, nanotechnology offers a promising strategy by protecting, targeting, and releasing active compounds to fight against these emerging strains. The aim of this study is to explore the antibacterial potential of nanoemulsions (NEs) as reported in the scientific literature. A literature review was carried out using searches performed in May 2023, on databases such as PubMed, Web of Science, and Scopus, utilizing the keywords "nanoemulsion", "antibiotic activity," "antibacterial activity," and "antimicrobial activity." All scientific articles related to the health area and published in the last 5 years were included. Several NE systems proved to be efficient in combating gram-positive and gram-negative bacterial strains in preclinical studies, often employing vegetable or essential oils as a matrix. Some studies use NEs as a vehicle for antibacterial drugs, while others develop NEs based on antibacterial oils and incorporate actives that act synergistically. All studies indicated that oil-based NEs with inherent antibacterial activity, even without the presence of drugs, had superior action against strains compared to non-emulsified oil, as well as other systems incorporating drugs or actives. Although the results are promising, further investigations and testing of formulations against resistant bacterial strains are necessary. This review aims to provide valuable insights for researchers and contribute to future advancements in this field.