Background: Urinary tract infection (UTI) is a common disease in sows due to intensification of pig production. Despite direct economic losses, UTI prevalence and respective microbial identification are still poorly studied.

Objective: The aims of this study were to identify the causative agents of UTI in sows through MALDI-TOF MS and to characterize their antimicrobial resistance profiles.

Materials and Methods: Urine samples from 300 sows of three herds from São Paulo State (Brazil) were screened for UTI; suggestive samples were submitted to bacterial isolation. Species identification was performed by MALDI-TOF MS and susceptibility profiles were determined using disc diffusion method.

Results: 128 samples suggestive of UTI were analyzed; 48% of the animals presented UTI caused by a single pathogen, while the remaining 52% presented mixed infection. Escherichia coli stood out with the highest frequency among both single and mixed infections. The Gram-positive were exclusively associated with 27% of single infections. The mixed infections were further classified into 49 profiles. The high frequency of multiresistant profiles stood out for most of the studied isolates.

Conclusions: MALDI-TOF MS enabled the identification of rare pathogens related to UTI which may represent higher risk for porcine health, especially considering high frequency of multiresistant profiles.

背景：随着养猪生产的集约化，尿路感染（UTI）是母猪的常见疾病。尽管造成了直接的经济损失，但尿路感染的患病率和相应的微生物鉴定仍然缺乏研究。

目的：本研究的目的是通过 MALDI-TOF MS 确定母猪泌尿道感染的病原体，并描述其抗菌谱特征。

材料和方法：对来自圣保罗州（巴西）三个猪群的 300 头母猪的尿液样本进行尿路感染筛查；提示性样本已被送去进行细菌分离。通过 MALDI-TOF MS 进行物种鉴定，并使用纸片扩散法确定敏感性曲线。

结果：分析了 128 个提示 UTI 的样本；48%的动物出现由单一病原体引起的尿路感染，而其余52%则出现混合感染。大肠杆菌在单一感染和混合感染中出现频率最高。革兰氏阳性菌与 27% 的单一感染完全相关。混合感染进一步分为49型。对于大多数研究的分离株来说，多重耐药谱的高频率都很突出。

结论： MALDI-TOF MS 能够识别与 UTI 相关的罕见病原体，这些病原体可能对猪的健康构成更高的风险，特别是考虑到多重耐药谱的高频率。