5PSQ-066 Evaluation of ceftazidime/avibactam use and clinical outcomes in patients with multidrug-resistant gram-negative infections

<h3>Background and Importance</h3> Antibiotic resistance is considered a major global public health issue. Ceftazidime/avibactam (CZA) was launched in July 2023 for the treatment of resistant gram-negative bacterial infections that do not respond to carbapenem antibiotics. Its use has been gradually increasing since it was newly included on the reimbursement list in February 2024. <h3>Aim and Objectives</h3> For the safe and effective use of CZA, this study aimed to investigate the status of CZA use and evaluate the appropriateness and clinical outcomes. <h3>Material and Methods</h3> Electronic medical records were retrospectively collected from adult patients who were admitted to tertiary hospital and treated with CZA for at least 3 days between July 2023 and July 2024. The status of CZA use, including indications, dosage, and administration was examined. Its efficacy was assessed in terms of the treatment success rate, 30-day mortality, and improvement in clinical laboratory results. <h3>Results</h3> Of the 229 patients who used CZA, 175 were included in this study in accordance with the exclusion criteria. The most frequently identified pathogen was <i>Klebsiella pneumoniae</i> (159 patients, 91%). Furthermore, 101 (58%) patients were administered with CZA for its approved indications, while 74 (42%) patients were treated for unapproved indications, such as bacteraemia. In addition, 168 (96%) patients adhered to the approved dosage and administration. The overall treatment success rate was 63%, but it did not significantly differ according to indication. Among the patients, 40 (29%) were treated with combination therapy. The treatment success rate against bacteraemia was significantly higher in patients who received monotherapy than in patients who received combination therapy (p&lt;0.05). Furthermore, 42 (24%) patients died within 30 days of their last CZA administration, but mortality had no significant differences in terms of indications or concomitant use of other antibiotics. <h3>Conclusion and Relevance</h3> In conclusion, the treatment success rate of monotherapy with CZA was significantly higher than that of combination therapy in patients with bacteraemia. Additionally, there were no significant differences observed in the treatment success rates or 30-day mortality in terms of indications. For the safe and effective treatment of multidrug-resistant infections, the appropriate use and management of CZA as a restricted antibiotic should be continuously monitored. <h3>References and/or Acknowledgements</h3> <h3>Conflict of Interest</h3> No conflict of interest