#1378 A single-center retrospective study on clinical characteristics and outcomes of extended-spectrum beta-lactamases positive acute pyelonephritis

Abstract Background and Aims The increase of extended-spectrum beta-lactamases (ESBL) releasing bacteria in acute pyelonephritis (APN) is a growing problem world-wide. Recently, little is known about the incidence, clinical features and outcomes of ESBL positive APN. This study intends to describe the epidemiology and clinical outcomes of ESBL positive APN. Method A retrospective study of 1631 culture positive patients with APN admitted from Jan, 2011 to Dec, 2019 in a single-center was performed. Adults over 18 years of age were included, and outpatient treatment, pregnant women, and transplant patients were excluded. Result A total of 2818 patients were diagnosed as APN during this period and causative bacteria was confirmed in1631 patients among them (57.9%). ESBL positive bacteria were found in 553 patients (33.9%). There were no differences in baseline characteristics between ESBL positive and negative groups. Most common strain was Escherichia coli, followed by Klebsiella and Pseudomonas species. The proportion of ESBL positive APN increased when evaluated at one-year intervals for 8 years (from 4.9% in 2011 to 20.9% in 2019). The rate of positive blood culture was higher in ESBL positive patients (39.2% vs 21.1%, p<0.001). Hospital stay was longer in ESBL positive patients (12.3 ± 2.2 vs. 5.4 ± 5.2, p<0.001) and the number of re-admission is higher (1.7 ± 1.3 vs. 1.2 ± 0.6, p<0.001). The incidence of acute kidney injury according to KDIGO was higher in ESBL positive groups (25.4% vs 12.3%, p<0.001). There was no hospital mortality between two groups. Conclusion We should attempt to detect ESBL positive bacteria through timely performing blood and urine culture and administer appropriate antibiotics if APN is clinically suspected because of poor clinical courses.