Daily Chlorhexidine Gluconate Bathing Reduces the Rate of Bloodstream Infections in Adults Undergoing Inpatient Hematopoietic Stem Cell Transplantation
Authors: Giri Vinay K. , Kegerreis Kristin G. , Ren Yi , Bohannon Lauren M. , Lobaugh-Jin Erica , Messina Julia A. , Matthews Anita , Allen Deborah H. , Mowery Yvonne M. , Saullo Jennifer L. , Jung Sin-Ho , Choi Taewoong , Gasparetto Cristina , Horwitz Mitchell E. , Long Gwynn D. , Lopez Richard D. , Rizzieri David A. , Sarantopoulos Stefanie , Chao Nelson J. , Sung Anthony D. 
Published: November 2019

Introduction: While hematopoietic stem cell transplantation (HSCT) has great therapeutic potential, intensive conditioning regimens and variability in time to stem cell engraftment result in a period of pancytopenia and immunosuppression in which patients are vulnerable to infection. Bloodstream infections (BSIs) occur in 20-45% of inpatient autologous and allogeneic transplant patients, leading to prolonged hospitalization and increased mortality. One method of infection prevention is daily application of the antiseptic chlorhexidine gluconate (CHG). Daily CHG bathing, either with a CHG wash or with application of CHG-impregnated cloths, has been shown to reduce the incidence of all-cause hospital-acquired BSIs in critically ill patients, such as those in the ICU, though very few studies include HSCT patients.
Methods: We conducted an observational cohort study to assess the impact of daily CHG bathing on the rate of BSIs among adults undergoing inpatient HSCT at the Duke University Medical Center. Patients were included if they were admitted for pre-transplant conditioning and inpatient monitoring for allogeneic or autologous HSCT from January 2016 through December 2018. CHG bathing was instituted in January 2017 for all patients admitted to the inpatient HSCT unit using 2% CHG-impregnated cloths (SAGE™), providing one year of data with no CHG bathing and two years of data with bathing. Patients were tracked from admission until unit discharge, transfer, or first infection. Laboratory-confirmed bloodstream infections (LCBI), central-line associated bloodstream infections (CLABSI), and mucosal barrier injury laboratory-confirmed bloodstream infections (MBI-LCBI) were determined per CDC/NHSN definitions. An additional variable of "clinically-significant infection" was recorded; this included both laboratory-confirmed BSIs and infections deemed significant by the treatment team but that did not meet CDC/NHSN criteria. For example, patients that were febrile, hypotensive, and treated with antibiotics, but with only one positive culture of a common commensal were deemed to have a clinically-significant BSI. Because not all patients adhered to CHG, patients were grouped into four categories by rate of daily CHG usage: High (>75%), Medium (50-75%), Low (1-49%), and None (0%). Baseline characteristics and clinical outcomes between groups were compared via ANOVA, Chi-squared test, or Cochran-Armitage two-sided trend test. Multivariate analysis using the Fine-Grey subdistribution hazard model was conducted to compare time to all infection variables, accounting for the effects of CHG usage, antibiotic prophylaxis regimen, and type of transplant.
Results: We evaluated 192 patients hospitalized for HSCT, including 118 (62%) allogeneic transplants and 74 (38%) autologous transplants. Of these, 25 (13%) had high CHG usage, 33 (17%) medium, 45 (23%) low, and 89 (46%) none. Demographics and transplant characteristics were evenly matched between the CHG usage groups with the exception that high usage groups were more likely to receive levofloxacin for antibiotic prophylaxis (p=0.003). Increased CHG usage was significantly associated with decreased incidence of clinically-significant infection (p=0.006), CLABSI (p=0.04), and MBI-LCBI (p=0.002) (Table 1). Multivariate analysis did not demonstrate a significant contribution of antibiotic prophylaxis regimen. No significant difference was found between CHG usage groups in median days to stem cell engraftment, incidence of febrile neutropenia or C. difficile infection, or rashes requiring medical treatment. There were no rashes attributable to CHG usage. Among patients who were VRE rectal swab negative on admission, there was a significant trend toward lower rates of VRE acquisition with increasing CHG usage (High CHG 13.6% vs No CHG 25.3%, p=0.02).
Discussion: Increased CHG usage is associated with a significant trend toward lower rates of clinically-significant infection, CLABSI, MBI-LCBI, and VRE colonization in adult inpatients undergoing HSCT. Effects are most strongly seen at >75% daily CHG usage. There were no adverse effects due to CHG application. The significant decrease in MBI-LCBI with topical CHG suggests an interaction between the skin microbial environment and enteric organisms. Therefore, further research exploring the effects of CHG on the skin and gut microbiota is warranted.

Disclosures
Gasparetto: BMS: Consultancy, Honoraria, Other: Travel, accommodations, or other expenses paid or reimbursed ; Janssen: Consultancy, Honoraria, Other: Travel, accommodations, or other expenses paid or reimbursed ; Celgene: Consultancy, Honoraria, Other: Travel, accommodations, or other expenses paid or reimbursed . Horwitz:Abbvie Inc: Membership on an entity's Board of Directors or advisory committees. Rizzieri:Celgene, Gilead, Seattle Genetics, Stemline: Other: Speaker; AbbVie, Agios, AROG, Bayer, Celgene, Gilead, Jazz, Novartis, Pfizer, Sanofi, Seattle Genetics, Stemline, Teva: Other: Advisory Board; AROG, Bayer, Celgene, Celltron, Mustang, Pfizer, Seattle Genetics, Stemline: Consultancy; Stemline: Research Funding. Sung:Novartis: Research Funding; Merck: Research Funding; Seres: Research Funding.