2668. Β Lactam and Other Antibiotic Allergies in Patients Undergoing Solid-Organ and Hematopoietic Cell Transplantation

BACKGROUND: Patients with reported β-lactam antibiotic allergies (BLA) are more likely to receive broad-spectrum antibiotics and experience adverse outcomes. There are limited data on the burden of β-lactam and other antibiotic allergies among solid-organ transplant (SOT) and hematopoietic cell transplant (HCT) recipients. METHODS: We reviewed records of first-time adult SOT or allogeneic HCT recipients from January 1, 2013 to December 31, 2017 to characterize allergy labels at the time of transplant. Days of hospitalization and inpatient antibiotic use for pre-specified antimicrobials were collected for the first 100 days post-transplant, and incidence rate ratios (IRR) comparing BLA to non-BLA group were calculated using negative binomial models adjusted for transplant type, age, and diagnosis of cystic fibrosis as appropriate. If the adjusted estimates were significantly different for SOT and HCT recipients, separate models were presented. RESULTS: Among 2153 SOT (65%) and HCT (35%) recipients, 634 (29%) reported any antibiotic allergy and 347 (16%) reported BLAs (Figure 1). Of 634 patients with allergy labels, the most common were penicillins (40%), sulfa (29%), and cephalosporins (17%); 31% reported allergies to ≥2 classes of antibiotics. The most commonly reported reaction to β-lactams was rash (42%), followed by unknown (18%) and hives (17%). In a multivariable model (Table 1), patients with reported BLAs had significantly higher use of vancomycin (IRR 1.35 [95% CI 1.13, 1.60], P < 0.001) and significantly lower use of ampicillin-sulbactam (IRR 0.13 [0.05, 0.39], P < 0.001) and piperacillin–tazobactam (IRR 0.39 [0.25, 0.62], P < 0.001) compared with those without BLAs. For some antibiotics, the effect of BLA varied by SOT/HCT (Table 2). No significant differences in Clostridioides difficile infection or inpatient days were noted. CONCLUSION: Transplant recipients have a high burden of reported antibiotic allergies, in particular BLAs. A BLA label was significantly associated with altered antibiotic prescribing in the early post-transplant period. Pre-transplant allergy evaluation may be helpful in directing antibiotic use following transplant as part of a comprehensive antibiotic stewardship program. [Image: see text] [Image: see text] [Image: see text] DISCLOSURES: All authors: No reported disclosures.