The purpose of this study was to establish a porcine model of urinary tract infection (UTI) with gram-positive uropathogens. Ten female domestic pigs were experimentally inoculated with human UTI isolates of Enterococcus faecalis (n = 3), Staphylococcus saprophyticus (n = 3), or Staphylococcus aureus (n = 4) and followed with regular urine samples. Bladders and kidneys were aseptically removed at termination (5-7 days post infection) and assessed by gross pathology and bacterial enumeration. Enterococcus faecalis (n = 3 of 3) and S. aureus (n = 2 of 4) successfully colonized the pig bladders. Inoculation with S. saprophyticus never resulted in detectable bacteriuria. All infected pigs had cleared the infection spontaneously before termination. Surprisingly, three (of four) pigs inoculated with S. aureus led to spontaneous infection with opportunistic pathogens. Also, one pig colonized with E. faecalis resulted in spontaneous infection with E. coli. In conlusion, the pig supports experimental UTI with E. faecalis for up to 24 h but not prolonged infection. S. aureus and S. saprophyticus fails to cause UTI in pigs and other animals should be considered for studying these pathogens.

Keywords: Enterococcus faecalis; Staphylococcus aureus; Staphylococcus saprophyticus; Urinary tract infection; large animal model; pig.

© 2024 The Author(s). APMIS published by John Wiley & Sons Ltd on behalf of Scandinavian Societies for Pathology, Medical Microbiology and Immunology.

本研究的目的是建立一个由革兰氏阳性尿路病原菌引起的猪泌尿系统感染（UTI）模型。实验中，10只雌性家猪被分别用人类 UTI 分离株中的粪肠球菌（n = 3），沙保葡萄球菌（n = 3）或金黄色葡萄球菌（n = 4）进行实验性接种，并定期采集尿样。在感染后5至7天终止时，无菌取出膀胱和肾脏并进行肉眼病理学检查及细菌计数。

粪肠球菌（n = 3/3）和金黄色葡萄球菌（n = 2/4）成功定植于猪的膀胱中。用沙保葡萄球菌接种从未导致可检测到的菌尿症。所有感染的猪在终止前都已自发清除感染。令人惊讶的是，有三只（共四只）接种金黄色葡萄球菌的猪自发起病并由机会致病菌引起感染。另外，一只被粪肠球菌定植的猪导致了大肠杆菌的自发性感染。总之，在这种模型中，猪支持实验性的用粪肠球菌引发 UTI 最多24小时但不支持长期感染。金黄色葡萄球菌和沙保葡萄球菌不能在猪身上引起UTI，因此应考虑其他动物来研究这些病原体。

关键词：粪肠球菌；金黄色葡萄球菌；沙保葡萄球菌；泌尿系统感染；大型动物模型；猪。