Prolonged fever is not a reason to change antibiotics among patients with uncomplicated community-acquired acute pyelonephritis

The study aimed to determine the pattern of fever resolution among febrile patients undergoing treatment for acute pyelonephritis (APN) and prove that switching therapy based solely on persistent fever beyond 72 hours of antibiotics treatment may be unwarranted. For the purpose of this study, non-responders were defined as those patients who had a persistent fever over 72 hours after the initiation of antibiotic therapy. Responders were defined as those patients who became afebrile in less than 72 hours after the initiation of antibiotic therapy. Clinical cure was defined as the complete resolution of all symptoms during antibiotic therapy without recurrence during the follow-up period. A total of 843 female patients with uncomplicated community-acquired APN met all inclusion criteria. The non-responder group comprised of 248 patients (29%), and the remaining patients constituted the responder group. The median initial C-reactive protein level was higher (15.6 mg/dl vs 12.6 md/dl, P < .001) and bacteremia was more frequent (31% vs 40%, P = .001) in the non-responder group. Escherichia coli (E. coli) was the most common pathogen in both groups; there was no significant difference between the groups in the etiology of APN. Antimicrobial resistance and extended spectrum β-lactamase producing strains had an increasing trend in the non-responder group but there was no significant difference between the groups. This study shows that it is difficult to identify patients at risk of uncomplicated community-acquired APN by antibiotic-resistant pathogens based exclusively on persistent fever. Patients with a prolonged fever for more than 72 hours show similar antibiotic susceptibility patterns and are not associated with adverse treatment outcomes. Therefore, switching of current antibiotics to broad-spectrum antibiotics should be reserved in this patient population until antibiotic susceptibility test results are available.