Clinical implications of healthcare-associated infection in patients with community-onset acute pyelonephritis

Background: Clinical and microbiological characteristics of healthcare-associated acute pyelonephritis (HCA-APN) have not been described in detail yet. We sought to delineate the differences between community-associated (CA)- and HCA-APN with specific interest in antibiotic resistance of causative microorganisms. Methods: We conducted a retrospective cohort study during a 1-y period at a large referral center. Patients who visited the emergency department with symptoms and signs of APN were included in the study population. Results: Among 319 cases with community-onset APN, 201 cases (63%) were classified as HCA-APN. Patients with HCA-APN had higher SOFA (sequential organ failure assessment) scores, longer length of hospital stay and a lower rate of complete response to antimicrobial therapy. Patients with complicated APN also had characteristics similar to those seen in HCA-APN. However, 14-day mortality rates were not different between CA-APN vs HCA-APN and between uncomplicated APN vs complicated APN. With regard to microbiological characteristics, Escherichia coli were less common in HCA-APN than in CA-APN (62.7% vs 93.2%, p < 0.001). Among E. coli isolates, quinolone resistance and extended-spectrum beta-lactamase (ESBL) production were more common in HCA-APN than in CA-APN (38.9% vs 12.7%, p < 0.001; 15.9% vs 0.8%, p < 0.001, respectively). Conclusions: HCA-APN, and complicated APN, represents a distinct subset of urinary tract infections with more antibiotic-resistant pathogens and worse outcomes, which physicians should consider to provide optimal treatment.