Abstract:To investigate the change in drugresistance of Pseudomonas aeruginosa (P. aeruginosa) to βlactam antibiotics in a hospital, so as to provide reference for treatment of P. aeruginosa infection.MethodsDrug sensitivity tests of 2 127 strains of P. aeruginosa isolated fom clinic between 1999—2007 to 18 kinds of antibiotics were analysed.ResultsResistance of P. aeruginosa to 18 kinds of βlactam antibiotics increased year by year during the past 9 years, there was significant difference between each year (P<0.05 or P<0.01). The total resistant rates to meropenem, imipenem and ceftazidime were below 30%. ConclusionP. aeruginosa was resistant to many kinds of βlactam antibiotics, and resistant rate increased year by year, in order to control and slow down the emergence of the resistant strains , the use of third generation cephalosporins and carbapenems should be properly controlled .