Department of Biology, Shahed University, Tehran-Qom Express way, Tehran, 3319118651, Iran.
Department of Biotechnology, Semnan University, Central Administration of Semnan University, Campus 1, Semnan, 35131-19111, I. R. of Iran.
Arch Microbiol. 2021 Aug;203(6):3483-3493. doi: 10.1007/s00203-021-02343-1. Epub 2021 Apr 27.
The Acinetobacter trimeric autotransporter adhesin (Ata) is an important virulence factor. The conserved region from the genomic sequence of a 6777bp/2258 amino acid of Acinetobacter baumannii ATCC®19606™ ata was explored. A 263aa of the C-terminal of Ata (rcAta) was expressed. The effect of rcAta on A. baumannii virulence was studied in a murine model. IgG and IgA were elicited and the mice groups challenged with A. baumannii showed significant survival rates from 66 to 100%. The bacterial loads were determined in the spleens, livers, and lungs of both control and test groups. The adhesion rate of A. baumannii to A549 cells in the presence of serum, cytotoxicity, mutagenicity, and biofilm disruption potential of rcAta were determined. Intraperitoneally challenged groups showed a significantly reduced bacterial load in the organs of the immunized mice. Intranasal challenge reduced 4 logs of bacterial CFU/g in the test group. The immunized mice sera reduced adherence of A. baumannii to A549 cells to 80%. No cytotoxic or mutagenic effect was detected. Biofilm disruption was significantly increased in the presence of immunized mice sera. Immunization with the conserved region of Ata significantly combats the virulence of A. baumannii which could be considered as a therapeutic strategy to control A. baumannii infections.
鲍曼不动杆菌三聚体自转运黏附素（Ata）是一种重要的毒力因子。对鲍曼不动杆菌 ATCC®19606™ ata 的 6777bp/2258 个氨基酸的基因组序列中的保守区域进行了探索。表达了 Ata 的 C 端 263 个氨基酸（rcAta）。在小鼠模型中研究了 rcAta 对鲍曼不动杆菌毒力的影响。诱导了 IgG 和 IgA，用鲍曼不动杆菌攻毒的小鼠组的存活率从 66%到 100%显著提高。在对照组和实验组的脾脏、肝脏和肺部中测定了细菌负荷。在血清存在的情况下测定了鲍曼不动杆菌对 A549 细胞的黏附率、细胞毒性、致突变性和 rcAta 的生物膜破坏潜力。腹腔内攻毒组中免疫小鼠的器官中的细菌负荷显著降低。鼻内攻毒使实验组的细菌 CFU/g 减少了 4 个对数级。免疫小鼠血清降低了鲍曼不动杆菌对 A549 细胞的黏附率至 80%。未检测到细胞毒性或致突变性。在免疫小鼠血清存在的情况下，生物膜破坏显著增加。用 Ata 的保守区域免疫可显著对抗鲍曼不动杆菌的毒力，这可被视为控制鲍曼不动杆菌感染的一种治疗策略。
