Effect of Inadequate Treatment in Adult Patients with Community-Acquired Acute Pyelonephritis Due to Enterobacterales...

Background/Objectives: First-generation cephalosporins are used in some countries, primarily in Latin America and other low-resource regions, as a first-line or alternative empirical treatment for patients with acute pyelonephritis (AP). This study aimed to evaluate the impact of inappropriate empirical therapy with cefazolin on the clinical outcomes of adult patients with community-acquired AP caused by resistant Enterobacterales, requiring hospitalization in two tertiary hospitals in Bogotá. Methods: This retrospective cohort study included hospitalized patients with community-acquired AP caused by Enterobacterales who received initial treatment with cefazolin at two tertiary-level institutions in Colombia (January 2013-2020). Inappropriate treatment was defined as a resistant isolate to cefazolin in the urine culture. Outcomes assessed included hospital stay, hospital mortality, and recurrence. Results: A total of 1031 patients were admitted, among whom 218 (21.1%) received inappropriate treatment. The mean length of stay was 4.8 (5.1) days, 996 (96.6%) survived to discharge, and 113 (11.0%) were admitted for a recurrence of AP. Inappropriate treatment had no impact on hospital stay (RRA 0.98, 95% CI 0.84-1.15) or hospital mortality (OR 1.02, 95% CI 0.47-2.19), although it was associated with a greater risk of admission because of recurrence (OR 3.7, 95% CI 2.4-5.8). Conclusions: We found that inadequate empirical treatment with cefazolin in adult patients with community-acquired acute pyelonephritis does not appear to change the length of hospital stay or in-hospital mortality in patients but is associated with an increased risk of readmission due to recurrence; this might favor the use of empirical narrow-spectrum antibiotics but with strategies that allow monitoring or early detection of microbiological non-eradication to prevent recurrence.