Partial ileectomy for intestinal Komagataella phaffii and Fusobacterium mortiferum co-infection

A 75-year-old woman presented with an acute onset of repeated hypogastralgia without evident predisposition, the symptoms worsened after ingestion of food or drink and were accompanied by nausea, vomiting, and diarrhoea. 6 days later, the patient developed abdominal burning pain and fever (maximum 37·7°C). She had previous history of type 2 diabetes, hypertension, and cerebral infarction for the past decade. On day 1 of admission, physical examination showed abdominal distension, pain, and rebound tenderness. A CT scan showed bowel-wall thickening. The initial diagnosis was peritonitis. Taking the empirical antibiotics piperacillin–tazobactam (4·5 g every 8 h) and levofloxacin (0·5 g every 12 h) for 1 day was not effective. The patient was then transferred to the Department of General Surgery at Zhujiang Hospital, with persistent abdominal pain, hypotension, and increased inflammatory indexes. Intestinal perforation, abdominal infection, and septic shock were considered, these were indications that justified emergency surgical exploration. Peritoneoscopic investigation showed oedematous ileum and intestinal wall sclerosis, then partial ileal resection was done. The patient was sent to the intensive care unit. After taking piperacillin–tazobactam (4·5 g) once, the patient still presented with fever and increased C-reactive protein. Mixed abdominal infection was considered and tigecycline (0·05 g) in conjunction with meropenem (1·0 g) was applied once. On day 2 of admission, the patient's abdominal pain alleviated, and ertapenem (1·0 g once daily) was used for 6 days according to antibiotic step-down therapy. On day 7 of admission, the patient's inflammatory indexes decreased but remained atypical. Meanwhile, the postoperative histopathology test revealed that the ileum was toxic and there was ischaemic intestinal necrosis, with extensive ulceration and mycosis (figure). The antibiotic was finally adjusted to fluconazole (0·2 g once daily) for 2 days and the patient was discharged with improvement. There was no recurrence after 3 months of follow-up. Next-generation sequencing of the ileum at follow-up suggested that Komagataella phaffii accounted for 12% and Fusobacterium mortiferum accounted for 62% of reads.