To improve the understanding of Actinotignum schaalii and expand clinical diagnosis and treatment approaches for infections caused by this bacteria.

The clinical data of a patient with complicated urinary tract infection caused by Actinotignum schaalii and admitted to Jiading Campus of Ruijin Hospital Affiliated to Shanghai Jiao Tong University School of Medicine in July 29th 2024 was analyzed, retrospectively. Relevant domestic and foreign literatures were searched to explore the characteristics, clinical diagnosis and treatment of this bacteria.

The patient, a female, 66 years old, was hospitalized for treatment due to urinary retention and repeated difficulty in urinating. Actinotignum schaalii was isolated from the clear mid-stream urine. CT urography showed bilateral renal pelvis and bilateral upper ureter dilation with hydrops, and bladder enlargement with multiple cords and diverticula, which may be caused by chronic cystitis. Transurethral resection of bladder tumor (TURBT) + transurethral resection of bladder neck (TURBN) were performed, and 1.5 g/time of Cefuroxime was intravenously infused twice a day. After three days’ anti-infection treatment, the patient improved and was discharged.

Actinotignum schaalii has atypical morphology and high culture requirements. Laboratory staff should pay attention to avoid missed detection. For urinary tract infections caused by this bacteria, β-lactam antibiotics such as Cephalosporins are recommended. Surgical patients should be alert to the occurrence of postoperative translocation infection.