Iliacus Myositis and Bacteremia Caused by Non-typhoidal Salmonella in a Healthy Adult: A Case Report

Typically, non-typhoidal Salmonella (NTS) causes gastroenteritis; however, NTS can also lead to extraintestinal manifestations like bacteremia, meningitis, and abscess in vulnerable populations such as children, elderly, and immunocompromised individuals. Extraintestinal manifestations in an immunocompetent patient are uncommon. Here, we report a case of iliacus myositis and bacteremia caused by NTS in a healthy adult. A previously healthy 23-year-old Japanese woman presented to the emergency room due to a one-day history of vomiting, abdominal pain, and diarrhea. She had a fever, and her blood test showed leukocytosis. Computed tomography (CT) of the abdomen and pelvis revealed a thickening of the ascending colon. She was diagnosed with gastroenteritis and treated with antibiotics. Blood culture at that time was negative, but Salmonella serogroup 09 was detected in stool culture. Subsequently, her symptoms improved; however, on day 13, she returned to our hospital complaining of pain in her left thigh. CT scan of the abdomen and pelvis revealed no abscess or muscle inflammation, but due to persistent symptoms, the patient was admitted to the hospital, and antibiotics were initiated. Salmonella serogroup 09 was detected from the blood culture obtained at the time of admission. Magnetic resonance imaging of the hip joint and CT of the abdomen and pelvis after admission revealed inflammation in the left iliacus muscle and an abscess near the left ilium. The patient was treated successfully with antibiotics. This case highlights two findings. First, NTS can cause bacteremia even in a healthy adult with no risk factors for bacteremia. Second, NTS bacteremia can cause complications in an immunocompetent adult. This case implies that even in the case of NTS infection in otherwise healthy individuals, if there are signs of bacteremia or complications, it is essential to conduct blood culture and additional tests.