​statement of the problem: Patients with leukemia are prone to infectious and often life-threatening complications. Evidence suggests that a specific oral microbiota may contribute to septicemia, which can delay antineoplastic treatment, compromise treatment efficacy, or even endanger patients' lives.

Purpose: This study investigated the prevalence of Staphylococcus aureus and Pseudomonas aeruginosa in the saliva of patients with acute myeloid leukemia who were candidates for bone marrow transplantation.

Materials and method: This cross-sectional study was conducted in 2019 in the Hematology-Oncology Department of Namazi Hospital, Shiraz University of Medical Sciences. The study included 28 patients with acute myeloid leukemia eligible for bone marrow transplantation as the case group and age- and sex-matched healthy individuals as the control group. Unstimulated saliva samples were collected to determine the frequency of Staphylococcus aureus and Pseudomonas aeruginosa. Data were analyzed using SPSS version 18, the chi-square test, and the independent t-test.

Results: In the patients with acute myeloid leukemia, 26 (86%) were positive for Staph-ylococcus aureus and 18 (60%) were positive for Pseudomonas aeruginosa. In the healthy group, 11 (22.9%) were positive for Staphylococcus aureus and 3 (6.2%) were positive for Pseudomonas aeruginosa. The frequency of Pseudomonas aeruginosa and Staphylococcus aureus in the saliva samples of patients with acute myeloid leukemia was significantly higher than in the healthy control subjects (p value < 0.05). Chi-square test showed no significant association between age and the frequency of bacteria (p value= 0.27).

Conclusion: In the current study, the frequency of Staphylococcus aureus and Pseudomonas aeruginosa in the saliva of patients with acute myeloid leukemia was higher than in the healthy control group.