Invasive Salmonella Enteritidis infection complicated by bacterial meningitis and vertebral osteomyelitis shortly after influenza A infection in an immunocompetent young adult

Abstract

Non-typhoidal Salmonella usually manifests as a self-limited acute gastroenteritis but may also cause severe invasive infections almost exclusively among children or immunosuppressed patients. A previously healthy 22-year-old man developed high fever with coma, multiple organ failure and shock. He had visited another hospital complaining of fever 2 days previously and was diagnosed with a common cold. No obvious site of infection was identified by radiology and a rapid test for influenza A virus was positive, indicating possible influenza-associated encephalopathy. However, blood as well as CSF culture yielded Salmonella enterica serotype Enteritidis. Therefore, the patient was considered to be suffering from bacterial meningitis with septic shock concomitant with influenza infection. Antiviral drugs and therapy for septic shock were initiated. He stabilized relatively quickly and his mental status dramatically improved. The patient denied preceding gastrointestinal symptoms, but mentioned that he received positive fecal Salmonella species culture results without medical intervention about 3 months previously. His laboratory values showed marked improvement but his elevated inflammatory markers and fever were sustained. On the 17th day of hospitalization, he complained of back pain and MRI showed lumbar vertebral osteomyelitis. This case indicates that (i) invasive Salmonella infection can be developed even in previously healthy adults; (ii) chronic carriage of Salmonella is a predisposing factor to development of invasive infections, and influenza infection may contribute to such "breakthrough infections"; (iii) attention to manifestation of metastatic extra-intestinal foci even after resolution of sepsis is necessary.

Keywords: Breakthrough infection; Immunocompetent patient; Influenza; Non-typhoidal Salmonella (NTS); Secondary bacterial infection.