BACKGROUND Leclercia adecarboxylata is a gram-negative rod, which is normally found in water and food. It is an emerging pathogen that affects immunocompromised patients, including patients with hematological malignancies or those receiving chemotherapy. Generally, L. adecarboxylata is considered a low-virulence pathogen with an excellent susceptibility profile, but some strains may be resistant to multiple antibiotics, such as b-lactams. Moreover, L. adecarboxylata is usually isolated as a part of polymicrobial cultures in immunocompetent individuals, but there have been cases where it was the only isolate. CASE REPORT A 74-year-old woman who was non-immunosuppressed and had multiple comorbidities was admitted with acute decompensated heart failure due to pneumonia. She was treated with multiple courses of antibiotics including amoxicillin-clavulanate and ciprofloxacin for pneumonia, but her infection worsened, and she had cardiopulmonary arrest. After resuscitation, she was stable for several days but suddenly became confused and hypotensive. The septic screen showed L. adecarboxylata bacteremia without a clear source, which was treated successfully with meropenem for 14 days. After the meropenem course, the patient developed diarrhea and was found to have severe Clostridium difficile infection. She did not respond to oral vancomycin and intravenous metronidazole and died. CONCLUSIONS This case illustrated an infection in a non-immunosuppressed individual by an organism that is considered an opportunistic pathogen, mainly affecting immunocompromised patients. The patient’s blood culture grew L. adecarboxylata, which was sensitive to all antibiotics but resolved with meropenem treatment. Owing to increasing L. adecarboxylata infections, we recommend further studies to understand the organism’s pathogenesis, risk factors, and resistance pattern.