Acute respiratory distress syndrome due to sepsis caused by Bacteroides ovatus after acute appendicectomy

Background Appendicectomy is generally a minimally invasive surgery, after which postoperative complications such as acute respiratory distress syndrome (ARDS) are rare. We describe a case of ARDS due to sepsis caused by Bacteroides ovatus after appendicectomy. Case presentation A man in his 60 s presented to our hospital with a chief complaint of right lower quadrant abdominal pain. He was diagnosed with acute appendicitis and underwent emergency laparoscopic appendicectomy. Cefmetazole was administered as a perioperative antibacterial drug. Postoperatively, the abdominal findings improved. However, on postoperative day three, bloody sputum and respiratory distress were observed. We performed thoracoabdominal computed tomography (CT) and observed bilateral pleural effusion and mottled frosted glass shadows extending to both lung fields. ARDS was diagnosed. We treated the patient with steroids and sivelestat sodium and switched the antibacterial drug to meropenem. The patient’s general condition improved. After the patient was treated, Bacteroides ovatus was isolated from preoperative blood culture, which was resistant to cefmetazole. Conclusions We encountered a case in which ARDS due to sepsis was caused by Bacteroides ovatus after acute appendicectomy. Blood culture to isolate the causative organism and determine its antimicrobial sensitivity after commencement of empiric antibiotics is important even in common diseases, such as acute appendicitis.