Urinary tract infection refers to inflammation of the urinary tract caused by pathogens that grow and multiply in the urinary tract and invade the mucosa or tissues of the urinary tract. Urinary tract infections are one of the most common infectious diseases, with 20% – 35% of women experiencing at least one urinary tract infection in their lifetime. With the 3rd highest number of shock deaths due to urinary tract infections among infectious diseases, urinary tract infections remain one of the most serious threats to human health. From acute pyelonephritis to asymptomatic bacteriuria, urinary tract infections have an unusually wide range of clinical presentations. Simple urinary tract infections are simple and effective to treat, while complex urinary tract infections are more difficult to treat. Recurrent infections and bacterial resistance due to long-term application of antibacterial drugs are one of the main reasons for treatment failure. I. Analysis of urinary tract infection strains Monitoring the composition and drug resistance of bacteria in urinary tract infections is of great value for clinical drug selection. The data of bacterial resistance monitoring in urine specimens from 2006 to 2007 from the National Bacterial Resistance Monitoring Network of the Ministry of Health showed that the most isolated bacteria were Escherichia coli, Enterococcus spp. and Klebsiella pneumoniae. Although the distribution of urinary tract bacteria was dominated by Gram-negative bacilli in patients of different genders, there were some differences in their specific species. Among female patients, Escherichia coli accounted for the majority, while among male patients, Pseudomonas aeruginosa, Enterobacter cloacae and Acinetobacter baumannii had a higher proportion. From 2008 to 2010, the top 5 isolates were Escherichia coli, Enterococcus faecalis, Enterococcus faecalis, Klebsiella pneumoniae and Proteus mirabilis. The antibacterial drugs with low resistance rates to Escherichia coli were carbapenems, fosfomycin, piperacillin/tazobactam and cefoperazone/sulbactam in that order. The antibacterial drugs with lower resistance rates to enterococci were, in order, linezolid, glycopeptides, fosfomycin and furantoin; the resistance rates of enterococcus faecalis to antibacterial drugs were generally higher than those of enterococcus faecalis. Overall, the causative organisms of female urinary tract infections in China are still mainly gram-negative bacilli represented by Escherichia coli, but the proportion of gram-positive bacteria such as Enterococcus spp. has increased, and the number of multidrug-resistant strains has increased compared with the previous ones. Third, the current status of bacterial drug resistance in male urine specimens The top 5 isolates in 2010 were Escherichia coli, Enterococcus faecalis, Enterococcus faecalis, Pseudomonas aeruginosa and Klebsiella pneumoniae in order. Among them, the resistance rates of P. aeruginosa to imipenem, amikacin and levofloxacin were 18.3%, 10.7% and 30.2%, respectively. The main causative organisms of urinary tract infection in men in China are still mainly Escherichia coli, with a high rate of resistance to quinolones; the proportion of Enterococcus and Pseudomonas spp. has increased; the vancomycin resistance rate of Enterococcus is still at a low level. Bacteria can acquire resistance to antibacterial drugs in various forms. The mechanisms related to the development of drug resistance in bacteria mainly include the production of β-lactamases, metalloenzymes and other biological enzymes with inactivating effects, changing the target of antimicrobial drugs to make it mutate with the effective binding of antimicrobial drugs, changing the permeability of the bacterial membrane to prevent the entry of antimicrobial drugs into the bacteria, and pumping out antimicrobial drugs to reduce the concentration of antimicrobial drugs in bacteria.