Drug resistance, also known as drug resistance, refers to the tolerance of microorganisms, parasites and tumor cells to therapeutic drugs. Once drug resistance occurs, the role of drugs will be significantly reduced. Since the first antibiotic penicillin was used in clinic in the 1940s, tens of thousands of antibiotics have been found and semi-synthesized all over the world, and nearly 100 antibiotics are commonly used in veterinary clinic. The long-term application of these antibiotics has achieved good results in the treatment of infectious diseases, but it has also made some bacteria resistant, and new drug-resistant strains have emerged continuously. For example, Pseudomonas aeruginosa is highly resistant to penicillin and other natural antibiotics. The emergence of bacterial resistance is a big problem in veterinary clinic, which can reduce or invalidate the efficacy of many commonly used antibacterial drugs, resulting in extremely difficult treatment. Due to drug adaptation or gene mutation, bacteria are resistant to drugs. On the one hand, drug resistance can be passed on to offspring through genetic genes, on the other hand, it can be passed on to sensitive bacteria, making sensitive bacteria become drug-resistant strains. Therefore, when using antibiotics in clinic, veterinarians must strictly grasp the indications of antibiotics, avoid abuse and prevent cross-infection caused by drug-resistant bacteria. Infections that can be controlled by one antibiotic do not use multiple combined applications. If you can use narrow-spectrum antibiotics, don't use broad-spectrum antibiotics.