Department of Microbiology, Laboratory of Bacteriology, Center of Biological Sciences, State University of Londrina, Rodovia Celso Garcia Cid PO-BOX 6001, Londrina, Paraná, 86051-980, Brazil.
Department of Preventive Veterinary Medicine, Laboratory of Avian Medicine, Agricultural Sciences Center, State University of Londrina, Londrina, Brazil.
Braz J Microbiol. 2020 Sep;51(3):1353-1362. doi: 10.1007/s42770-020-00240-1. Epub 2020 Feb 17.
Given the need to understand the virulence profile of Proteus mirabilis isolates from cellulitis in broiler chickens and their ability to cause lesions, the present study aimed to characterize genotypically and phenotypically the virulence profiles of two strains of P. mirabilis isolated from cellulitis in broilers, as well as to evaluate their ability to experimentally reproduce the lesions in vivo. The strain with the highest virulence potential (LBUEL-A33) possessed mrpA, pmfA, ucaA, atfA (fimbriae), zapA, ptA (proteases), hpmA (hemolysin), and ireA (siderophore) genes, formed a very strong biofilm, and expressed the pattern of aggregative adhesion and cytotoxicity in Vero cells. The strain with the lowest virulence potential (LBUEL-A34) did not present the pmfA and ucaA genes, but expressed the pattern of aggregative adhesion, formed a strong biofilm, and did not show cytotoxicity. Both strains developed cellulitis in an animal model within 24 h post-inoculation (PI), and the degree of lesions was not significantly altered up to 120 h PI. The LBUEL-A33 strain was also inoculated in combination with an avian pathogenic Escherichia coli (APEC 046), and the lesions showed no significant changes from the individual inoculation of these two strains. Histological analysis showed that the LBUEL-A33 strain developed characteristic cellulitis lesions. Thus, both strains of P. mirabilis isolated in our study have several virulence factors and the ability to develop cellulitis in broilers.
鉴于了解奇异变形杆菌从肉鸡丹毒分离株的毒力特征及其引起病变的能力的必要性，本研究旨在对从肉鸡丹毒中分离的两株奇异变形杆菌进行基因和表型特征分析，以评估它们在体内实验性复制病变的能力。毒力潜力最高的菌株（LBUEL-A33）具有 mrpA、pmfA、ucaA、atfA（纤毛）、zapA、ptA（蛋白酶）、hpmA（溶血素）和 ireA（铁载体）基因，形成非常强的生物膜，并在 Vero 细胞中表现出聚集性粘附和细胞毒性模式。毒力潜力最低的菌株（LBUEL-A34）不具有 pmfA 和 ucaA 基因，但表现出聚集性粘附模式，形成强生物膜，并且不表现细胞毒性。两种菌株在接种后 24 小时内（PI）在动物模型中均发展为丹毒，并且直到 120 小时 PI 时病变程度没有显著改变。LBUEL-A33 菌株还与禽致病性大肠杆菌（APEC 046）混合接种，并且与单独接种这两种菌株相比，病变没有明显变化。组织学分析表明，LBUEL-A33 菌株发展出特征性的丹毒病变。因此，本研究中分离的两株奇异变形杆菌均具有多种毒力因子和在肉鸡中引起丹毒的能力。
