Bloodstream infection caused by Campylobacter ureolyticus and Peptoniphilus asaccharolyticus temporally associated with upper gastrointestinal endoscopy: A case report

Campylobacter ureolyticus is an anaerobic gram-negative bacillus frequently linked to gastroenteritis and extra-intestinal infections, with limited reports of bacteremia. This article describes a case of bacteremia caused by C. ureolyticus and Peptoniphilus asaccharolyticus that was temporally associated with endoscopic hemostasis for gastric ulcer bleeding. A 71-year-old Japanese woman with breast cancer was admitted to our hospital for melena and anemia. Upper gastrointestinal endoscopy revealed a bleeding gastric ulcer; accordingly, endoscopic hemostasis with hemoclips was performed. She developed a fever the day after admission, and blood cultures obtained on the third day of admission were positive for gram-negative rods and gram-positive cocci after approximately 58 h of incubation. The gram-positive cocci were identified as P. asaccharolyticus using the VITEK2 system. However, the gram-negative rods could not be identified using the VITEK2 system or matrix-assisted laser desorption/ionization time-of-flight mass spectrometry with either VITEK MS or the Biotyper system. Subsequent 16S ribosomal RNA sequencing confirmed the isolate as C. ureolyticus . Intravenous ampicillin/sulbactam (12 g/day) and vancomycin (1 g/day) were administered for 11 and 5 days, respectively, followed by amoxicillin/clavulanic acid (1500 mg/day) for 14 days. After antimicrobial therapy, the patient's condition gradually improved, and she was discharged on the 14th day of hospitalization. In conclusion, we report a case of bloodstream infection caused by C. ureolyticus and P. asaccharolyticus that was temporally associated with upper gastrointestinal endoscopy. C. ureolyticus could not be identified using conventional methods and required 16S rRNA gene sequencing for accurate identification. Our findings emphasize the need to apply advanced diagnostics that utilize molecular biology techniques for accurate pathogen identification.