The main danger of P. aeruginosa is the infections it causes. P. aeruginosa can cause a variety of infections, including skin, eye, external ear, nose, mouth, urinary tract, lung, bone and joint infections. There are few types of antibacterial drugs that are effective against P. aeruginosa, and most of them can only be given intravenously, and there are even fewer oral drugs that are effective against P. aeruginosa, so it is very difficult to treat. In addition, P. aeruginosa can produce biofilm, many anti-infective drugs are difficult to penetrate the biofilm, so the treatment effect is poor. In addition, Pseudomonas aeruginosa often causes various chronic infections, such as urinary tract infections or bronchial dilatation, the bacteria will exist in the infection site for a long time, although the use of effective antibacterial drug treatment can temporarily control the growth of bacteria, but can not really remove the bacteria, so it is often easy to cause recurrent disease, and some patients may even carry the bacteria for life. Therefore, the harm of Pseudomonas aeruginosa is mainly caused by the type of infection, difficult to treat, and many will cause chronic infection or even lifelong infection.