A trend in prevalence of antimicrobial use and appropriateness of antimicrobial therapy in an acute care hospital from 2018 to 2019: repeated prevalence surveys in Japan

The supply of cefazolin has been reduced dramatically since March 2019 in Japan. However, no studies have evaluated the effects of cefazolin shortage on the appropriateness of antimicrobial use. Therefore, we compared the appropriateness of inpatient antimicrobial drug use between the two surveys conducted in August 2018 and August 2019 in a Japanese hospital with no supply of cefazolin since the cefazolin shortage. In the 2019 survey, a total of 275 patients were included, and 256 patients were included in the 2018 survey. The prevalence of antimicrobial drug use did not change from 2018 to 2019 (28.5% versus 28.7%; p = 0.96). The proportion of cefazolin in all antimicrobial drugs used on the survey date significantly decreased from 2018 to 2019 (24.1% versus 0.0%; p < 0.001). The proportion of appropriate antimicrobial use in all antimicrobial therapies tended to be lower in 2019 than in 2018 (41.2% versus 60.6%; p = 0.06), and the proportion of unnecessary use of a broader spectrum of antimicrobial drugs significantly increased from 2018 to 2019 (4.7% versus 37.3%; p = 0.002). The shortage of cefazolin might lead to inappropriate use of other antimicrobial drugs.