 Phenotypic resistance occurs when bacteria are able to survive exposure to an antibiotic despite having no genetic mutations that confer resistance. This type of resistance is often seen in biofilm formation where bacteria form a protective layer around themselves, allowing them to survive longer than if they were exposed to the same antibiotic and liquid suspension. Additionally, phenotypic resistance can arise due to environmental factors such as nutrients, temperature, and pH levels. This article was authored by Jose L. Martinez and Fernando Corona.