773. First National Survey of Antibiotic Use Prescribed by All Dentists in Japan from 2015 to 2017 using the National Database of Health Insurance Claims and Specific Health Checkups of Japan (NDB).

Background The surveillance of antimicrobial use (AMU) among medical doctors and dentists is a key component of the Japanese national plan on antimicrobial resistance (AMR). However, there are no epidemiological studies of AMU among dentists in Japan. We aimed to evaluate the epidemiology of AMU among dentists in Japan and investigate the factors affecting inappropriate prescribing. Methods Total AMU among dentists in Japan between 2015 and 2017 was analyzed by using the National Database of Health Insurance Claims and Specific Health Checkups of Japan (NDB), from the Ministry of Health, Labor and Welfare of Japan, which accounted for 98% of total claim data in Japan. Antimicrobials were classified by the World Health Organization (WHO) Anatomical Therapeutic Chemical Classification. The WHO measures antimicrobial usage by using the Defined Daily Dose per 1,000 inhabitant-days (DID) parameter. The patterns of oral AMU in 2017 in outpatient settings were compared between in-house and outside prescriptions. Results DID values of total AMU in 2015, 2016, and 2017 were 1.23, 1.22, and 1.21, respectively (Figure 1). In 2017, the DID value of oral AMU in outpatient settings was 1.19 (98.4%), comprising cephalosporins (0.76, 63.6%), macrolides (0.23, 18.9%), penicillins (0.12, 10.2%), and quinolones (0.07, 5.5%). DID values of oral AMU in outpatient settings were compared for in-house (0.89, 74.4%) and outside (0.31, 25.6%) prescriptions; in-house resulted in a higher proportion of oral cephalosporins (0.60, 66.9% vs. 0.17, 54.1%), but a lower proportion of oral penicillins (0.08, 9.0% vs. 0.04, 13.8%) (Table 1). Conclusion Oral AMU in outpatient settings comprised the highest proportion of antibiotic prescribing by dentists in Japan (98.4%). Oral cephalosporins, the predominant drug type and thought to result from inappropriate prescribing in general, were more frequently prescribed in-house than outside. To tackle AMR, further studies are needed to determine the patient and dentist characteristics encouraging cephalosporin prescription. Disclosures All authors: No reported disclosures. [ABSTRACT FROM AUTHOR]