Efficacy of Prolonged Antibiotic Therapy for Renal Cyst Infections in Polycystic Kidney Disease.

Objective: To determine the impact of antibiotic therapy (ATBT) on outcomes of renal cyst infection (CyI) in patients with polycystic kidney disease.

Patients And Methods: We undertook a single-center retrospective study of CyI in autosomal dominant polycystic kidney disease (January 1, 2000, through December 31, 2018). Cyst infections were classified as definite (microbiologically proven), probable (radiologic signs), or possible (clinical or biologic signs only). We studied the determinants of ATBT failure (persistence of infection beyond 72 hours of microbiologically adequate initial ATBT, with requirement for ATBT change, cyst drainage, or nephrectomy) and recurrences (>14 days after the end of ATBT).

Results: Among 90 patients, 139 CyIs (11 definite, 74 probable, 54 possible) were compiled. Cultures were positive in 106 of 139 (76%) episodes, with Escherichia coli found in 89 of 106 (84%). Treatment failures and recurrences within 1 year of follow-up were more frequent in definite/probable CyI (20/85 [34%] and 16/85 [19%]) than in possible CyI (2/54 [4%] and 4/54 [7%]; P<.01 and P=.08, respectively). Male sex (odds ratio [OR], 7.79; 95% CI, 1.72 to 46.68; P<.01), peak C-reactive protein level above 250 mg/L (OR, 7.29; 95% CI, 1.78 to 35.74; P<.01; to convert C-reactive protein values to nmol/L, multiply by 9.524), and cyst wall thickening (OR, 7.70; 95% CI, 1.77 to 43.47; P=.01) but not the modalities of initial ATBT were independently associated with higher risk of failure. In a Cox proportional hazards model, kidney transplant recipients exhibited higher risk of recurrence (hazard ratio, 3.76; 95% CI, 1.06 to 13.37; P=.04), whereas a total duration of ATBT of 28 days or longer was protective (hazard ratio, 0.02; 95% CI, 0.00 to 0.16; P<.001), with an inverse correlation between duration and recurrence (81% for treatment <21 days, 47% for 21 to 27 days, 2% for ≥28 days; P<.0001).

Conclusion: Initial first-line ATBT had no significant effect on renal CyI treatment failure. Treatment duration of 28 days and longer reduced recurrences.