Pseudomonas is widely distributed in nature. There are more than ten species that are pathogenic to humans and animals. Pseudomonas aeruginosa (Pseudomonas aeruginosa) is the most important in medicine. This genus of bacteria is weakly invasive and is generally considered to be a conditional pathogen. When the body's immune function is impaired or defective, it can cause serious or even fatal infections; patients after surgery or certain treatment operations (tracheotomy, retention of urinary catheters, etc.) are also prone to infection with this bacteria, so it is also one of the important pathogens of hospital-acquired infections. Pseudomonas aeruginosa can infect the blood, respiratory, central nervous, urinary and other systemic tissues of the human body, causing a series of lesions.