Reply: Is Taking Blood Cultures Indicated in Acute Pyelonephritis Patients Who Have Used Antibiotics before Presentation?

We appreciate the interest in our article and the opportunity to present our results more articulately. Indeed, we agree with the comments that the data on the number of patients who had started antibiotics before the enrollment are necessary to explain the high rate of pathogen isolation in blood-only cultures and to support our hypothesis. However, unfortunately, we did not collect patients’ data on antibiotic use before their enrollment in this prospective study. To identify the clinical characteristics of the blood-only culture-positive group, we performed a comparative analysis of the clinical characteristics of the blood-only culture-positive group and the other groups, but could not find significant differences between the blood-only and blood-and-urine culture-positive groups. However, compared with the urine-only culture-positive group, the blood-only culture-positive group had more patients aged ≥70 years (44.2% vs. 30.3%, P = 0.017), with a Charlson comorbidity index of ≥1 (53.8% vs. 39.7%, P = 0.022), and with a Pitt score of ≥1 (46.2% vs. 31.8%, P = 0.041). On the basis of this analysis, we could recommend that blood cultures are especially necessary for old patients with acute pyelonephritis who have underlying diseases and severe clinical presentations.