Limited Utility of Outpatient Surveillance Blood Cultures in Hematopoietic Cell Transplant Recipients on High-Dose Steroids for Treatment of Acute Graft-versus-Host-Disease.

BACKGROUND: Steroids used to treat acute graft-versus-host-disease (GVHD) are thought to blunt clinical symptoms of infection. We aimed to assess the value of weekly surveillance blood cultures (SBCs) drawn in an outpatient setting from hematopoietic cell transplant (HCT) patients receiving high-dose steroids. We hypothesized that most positive outpatient surveillance cultures would be low-pathogenicity gram positive organisms and would lead to excess vancomycin therapy.

METHODS: We conducted a retrospective review of blood cultures collected from a cohort of adult HCT patients enrolled in a clinical trial of acute GVHD therapy with high-dose steroids (prednisone-equivalent doses ≥ 0.5 mg/kg/day) between April 2009 and May 2013. SBCs were defined as those collected weekly from central venous catheters (CVCs) in the outpatient setting while patients were receiving high-dose steroids. Cultures obtained as part of a symptom work-up or as follow-up for documented bacteremia were excluded. Clinical data were collected using center databases supplemented by medical record review.

RESULTS: A total of 127 HCT recipients were eligible for inclusion in the study. A total of 1015 SBCs were obtained, with a median of 8 cultures (interquartile range [IQR]; 5-10) per patient. Forty-two organisms were isolated from 36 of 1015 cultures (3.5%) in 30 unique patients, or 1 positive culture per 28 blood cultures drawn. The most frequently detected organism was coagulase-negative Staphylococcus (25/1015 [2.5%]). Gram negative organisms were rare (4/1015 [0.4%]. Antibiotics were administered the majority of patients with positive surveillance cultures (33/36 [92%]). Six were admitted to the hospital for treatment; none needed intensive care or died from their bacteremia. Vancomycin was the most frequently administered antibiotic, comprising 256 of 376 (68%) total days of antibiotic received by the cohort with a median duration of 10 days (IQR: 7, 14).

CONCLUSIONS: Weekly outpatient surveillance blood cultures obtained from asymptomatic patients on high-dose glucocorticoids for treatment of acute GVHD after allogeneic HCT were infrequently positive, and the majority of organisms were low-pathogenicity organisms. Surveillance blood cultures also led to excess antibiotic exposure and costs, suggesting benefits of such ambulatory screening may be of limited value in this setting.