Submandibular gland abscess and bacteremia caused by Dialister micraerophilus in a patient with Sjögren's syndrome: a case report.

Background: Infection caused by Dialister micraerophilus (D. micraerophilus), a slow-growing, anaerobic or microaerophilic, small gram-negative coccobacillus, has been rarely reported, and its clinical characteristics remain insufficiently defined.

Case presentation: A 59-year-old woman presented with a submandibular gland abscess and bacteremia caused by D. micraerophilus. The underlying etiology of this infection was salivary gland dysfunction associated with Sjögren's syndrome (SS), which led to submandibular gland abscess formation and subsequent hematogenous dissemination, resulting in bacteremia. Identification of D. micraerophilus was achieved using matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) and 16 S rRNA gene sequencing. The patient achieved complete clinical recovery following intravenous piperacillin-tazobactam (4.5 g every 8 h) during hospitalization, followed by a 10-day course of oral amoxicillin-clavulanic (0.375 g every 8 h) after discharge.

Conclusions: This case describes bacteremia with D. micraerophilus in a patient with SS complicated by a submandibular gland abscess. Clinical management of such patients should emphasize oral hygiene education and rigorous aseptic techniques during dental procedures to reduce the risk of infection.