de Souza Lima Ewerton, de Oliveira Filho Ruy Brayner, Malta Karla Campos, Pires Isabelle Caroline, Rosa Danillo Sales, Chideroli Roberta Torres, Aburjaile Flavia Figueira, de Jesus Sousa Thiago, Ramos Rommel Thiago Jucá, Góes-Neto Aristóteles, de Castro Soares Siomar, Brenig Bertram, de Carvalho Azevedo Vasco Ariston, da Costa Mateus Matiuzzi, de Carvalho Fernandes Artur Cezar
Laboratory of Preventive Veterinary Medicine, Veterinary Science Department, Universidade Federal da Paraíba, Areia, Paraíba, Brazil.
Veterinary Hospital, Center of Agrarian Sciences, Universidade Federal da Paraíba, Areia, Paraíba, Brazil.
Braz J Microbiol. 2025 Jul 1. doi: 10.1007/s42770-025-01723-9.
Corynebacterium pseudotuberculosis is a bacterium that causes significant economic damage to farmers, mainly in the semiarid region of Northeastern Brazil. In this context, only biovar ovis has been reported, and it is widespread in small ruminants. However, this report describes the first equine case in Brazil attributable to a biovar equi. Clinically, it is the causative agent of ulcerative lymphangitis, mastitis, necrotic and ulcerative dermatitis. A Quarter Horse from the semiarid Northeast presented ulcerative lymphangitis. Culture, nitrate reduction test, MALDI-TOF, and whole-genome sequencing identified the Cp_Eq_BR01 strain as biovar equi. The 2.37 Mb genome shared > 98% nucleotide identity with other equi strains and clustered most closely with the Chilean isolate E19. Although no unique determinants of virulence or resistance were found, the observed genomic clonality suggests potential for rapid transboundary spread. This first Brazilian detection broadens the recognized host range, alerts the farmer's national equine to a new threat, and highlights the need for routine nitrate testing, and updated movement control policies for equines.
伪结核棒状杆菌是一种给养殖户造成重大经济损失的细菌，主要集中在巴西东北部的半干旱地区。在此背景下，仅报道过绵羊生物变种，且在小型反刍动物中广泛传播。然而，本报告描述了巴西首例归因于马生物变种的马病例。临床上，它是溃疡性淋巴管炎、乳腺炎、坏死性和溃疡性皮炎的病原体。一匹来自半干旱东北部地区的夸特马出现了溃疡性淋巴管炎。通过培养、硝酸盐还原试验、基质辅助激光解吸电离飞行时间质谱（MALDI-TOF）和全基因组测序，将Cp_Eq_BR01菌株鉴定为马生物变种。该2.37 Mb的基因组与其他马菌株的核苷酸同一性>98%，并且与智利分离株E19的聚类关系最为密切。虽然未发现独特的毒力或抗性决定因素，但观察到的基因组克隆性表明其具有快速跨境传播的可能性。巴西的这首次检测拓宽了已确认的宿主范围，使该国养马户警惕到一种新威胁，并突出了对马进行常规硝酸盐检测以及更新流动控制政策的必要性。
