Thoracic Empyema Caused by Campylobacter rectus

Campylobacter rectus is a campylobacterium considered to be a primary periodontal pathogen. Thus, C. rectus has rarely been isolated from extraoral specimens, especially in the thoracic region. We herein report a case of thoracic empyema in which Campylobacter infection was suspected after Gram staining of the pleural effusion, and C. rectus was isolated using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Fusobacterium nucleatum was also detected. Molecular identification was performed using polymerase chain reaction amplification and a sequencing analysis of the 16S rRNA gene. Estimation of the causative bacteria using Gram staining led to the proper culture and identification of the causative bacteria.