401. Pneumocystis jirovecii Pneumonia in Renal Transplant Recipients After a 6-Month Trimethoprim–Sulfamethoxazole Prophylaxis: A Case–Control Study

Background Pneumocystis jiroveci pneumonia (PCP) is an important cause of morbidity and mortality in kidney transplant recipients (KTRs). Chemoprophylaxis with trimethoprim-sulfamethoxazole (TMP-SMX) is recommended about 6–12 months after solid-organ transplantation. However, PCP occasionally occurs after the recommended prophylaxis periods. The aim of this study was to investigate the incidence and risk factors for PCP in KTRs with 6-month TMP-SMX prophylaxis. Methods We performed a case–control study of adult patients diagnosed with PCP from 1999 to 2015 in a tertiary care hospital. All patients received 6-month PCP prophylaxis with TMP-SMX after kidney transplantation (KT). If there were rejection episodes, PCP prophylaxis was provided for additional 3 months. During the study period, CMV viremia was not indication of PCP prophylaxis because of the concern of the nephrotoxicity of TMP-SMX. We defined the classification of early or late-onset PCP as one year after transplantation. Results Among 3,941 kidney or pancreas-kidney transplant recipients, 67 (1.7%) patients developed PCP after the discontinuation of TMP-SMX prophylaxis. Among them, patients who was transferred from other hospitals (n = 14) and pancreas-kidney transplant recipients (n = 6) were excluded. Finally, 47 of KT PCP and 94 control patients were included. Of the 47 patients with PCP, 24 (51%) revealed early PCP while the remaining 23 (49%) exhibited late PCP. Duration of PCP prophylaxis was similar between case and control (median 6 months, respectively). In multivariate analysis, rejection (OR, 3.9; 95% CI, 1.4–11.1) and cytomegalovirus infection (OR, 2.4; 95% CI, 1.0–5.8) were independently associated with the development PCP after TMP-SMX prophylaxis. Rejection or CMV viremia were observed in 70% of patients with PCP patients. Time to development of PCP after rejection (median 6 months; IQR 5–19 months) was slightly shorter than that after CMV viremia (median 9 months; IQR 5–12 months), although this difference did not reach any statistical significance (P = 0.18). Conclusion Rejection and CMV viremia appear to be risk factors for the development of PCP after completing early transplantation period chemoprophylaxis. Our data suggest that at least 6- to 9-month chemoprophylaxis for PCP may be needed for KTRs with rejection or CMV viremia. Disclosures All authors: No reported disclosures.