Background: This study aimed to determine the risk factors of infectious diarrhea in patients undergoing chemotherapy or hematopoietic stem cell transplantation for hematological malignancies. Materials and Methods: This was a prospective, observational study. Patients in whom the infectious agent was determined by laboratory examination were considered to have infectious diarrhea. Patients with diarrhea were categorized as infectious or unidentified and compared in terms of demographic data, treatments, risk factors, laboratory findings, and prognosis. Results: A total of 838 patients were hospitalized, among which 105 patients who met the inclusion criteria were included (12.5%). The patients were divided into two groups: 67 (63.8%) with unidentified diarrhea and 38 (36.2%) with infectious diarrhea. There were no differences between these groups in terms of age, sex, types of hematological malignancies, and presence of comorbidities. The most commonly isolated microorganism was Clostridioides difficile (12.4%). The rate of corticosteroid use was higher in the group with infectious diarrhea (39.5%) than in the group with unidentified diarrhea (7.5%) (P <0.001). The rate of granulocyte colony-stimulating factor (GCSF) use was higher in patients with unidentified diarrhea than in patients with infectious diarrhea (67.2% vs. 42.1%, P=0.022). The median duration of diarrhea was 9 (4–10) days in the group with infectious diarrhea and 5 (3–8) days in the group with unidentified diarrhea (P=0.012). According to the multivariate logistic regression model, corticosteroid treatment increased the risk of infectious diarrhea by a 4.75-fold (95% confidence interval [CI], 1.32–17.02) times. Moreover, the duration of diarrhea may result in a 1.15 (95% CI, 1.02–1.31) fold increase in the risk of infectious diarrhea, while GCSF treatment had a 2.84 (1/0.35) (95% CI, 0.12–0.96) fold risk-reducing effect against infectious diarrhea. Conclusion Infectious diarrhea lasts longer than unidentified diarrhea in patients with hematological malignancies. Although corticosteroid use is a risk factor for developing infectious diarrhea, GCSF use has a protective effect.

Background: Bacteremia is a common complication in hematopoietic stem cell transplant (HSCT) recipients. Prophylactic fluoroquinolone is recommended and used in these individuals. Breakthrough infections can occur with fluoroquinolone-resistant strains.We aimed to identify the incidence, resistance, and risk factors for bacteremia in HSCT recipients receiving fluoroquinolone prophylaxis. Materials and Methods: This retrospective study was performed on patients who received fluoroquinolone prophylaxis and underwent autologous and allogeneic HSCT between 2015 and 2019. The incidence of bacteremia, comorbidity, treatment, and invasive procedures was compared in these patients with and without bacteremia. Results: There were 553 patients included in the study, 68 (12.3%) had bacteremia. The incidence of bacteremia is 8.2% of autologous HSCT recipients and 18.4% of allogeneic HSCT recipients. The significant risk factors associated with bacteremia were steroidusing (odds ratio [OR]:13.83, 95% confidence interval [CI]: 2.88 - 66.40), higher Charlson Comorbidity Index (CCI)-mean (OR: 1.57, 95% CI: 1.15 - 2.16), diabetes mellitus (OR: 4.29, 95% CI: 1.11 - 16.48) in autologous HSCT, steroid-using (OR: 6.84, 95% CI: 1.44 - 32.33), longer duration of neutropenia (OR: 1.05, 95% CI: 1.01 - 1.09) using central venous catheter (OR: 7.81, 95% CI: 1.00 - 61.23) in allogeneic HSCT. Seventy-three pathogens were isolated from a total of 68 bacteremia episodes. The most commonly occurring agents were Escherichia coli, Klebsiella pneumoniae and Enterococcus spp. Resistance to fluoroquinolones was 87.2%, 70.0% and 60.0% among these strains, respectively. Conclusion High CCI, diabetes mellitus, use of steroids and long-term neutropenia and use of central venous catheters were significantly associated with the breakthrough bacteremia in HSCT recipients receiving fluoroquinolone prophylaxis. Fluoroquinolone prophylaxis may reduce the incidence of bacteremia but may select strains resistant to fluoroquinolone.