摘要
      副谷病毒是鸡传染性鼻炎的病原体，鸡传染性鼻炎是一种全球分布的急性呼吸道疾病，给鸡的生产造成严重的经济损失。副谷藻是一种革兰氏阴性细菌，可释放外膜囊泡（OMV）。在本研究中，对副伞藻分离株P4chr1及其OMV进行了比较基因组分析，并研究了通过OMV转移抗生素抗性基因（ARGs）的能力。测序和数据分析表明，副伞藻P4chr1的基因组大小约为2.77 Mb带25 kb耐受岛，涵盖6种类型的抗生素和11种ARGs。其OMV的基因组大小约为2.69 Mb，覆盖了P4chr1基因组长度的97%和几乎所有的基因序列。在含有抗生素（氯霉素、红霉素、四环素或链霉素）的平板上，将纯化的和DNase处理的并殖吸虫P4chr1 OMV与抗生素敏感的并殖线虫Modesto菌株共培养，并在平板上生长的菌落中检测到相应的ARG。然而，使用抗菌药物敏感性测试，我们发现OMV递送的ARGs不是持久的，而是仅在含有抗生素的平板上短暂出现。抗生素耐药性和ARGs在第二次细菌传代时消失。
ABSTRACT
Avibacterium paragallinarum is the etiological agent of infectious coryza, an acute respiratory disease of chickens that is globally distributed and causes serious economic losses for chicken production. A. paragallinarum is a Gram-negative bacterium that releases outer membrane vesicles (OMVs). In this study, a comparative genomic analysis of A. paragallinarum isolate P4chr1 and its OMVs was carried out, and the ability to transfer antibiotic resistance genes (ARGs) via the OMVs was studied. Sequencing and data analyses demonstrated that the genomic size of A. paragallinarum P4chr1 was approximately 2.77 Mb with a 25 kb tolerance island that covered six types of antibiotics and 11 ARGs. The genomic size of its OMVs was approximately 2.69 Mb, covering 97% of the genomic length and almost all the gene sequences of P4chr1. Purified and DNase-treated A. paragallinarum P4chr1 OMVs were cocultured with the antibiotic-sensitive A. paragallinarum Modesto strain on an antibiotic (chloramphenicol, erythromycin, tetracycline, or streptomycin)-containing plate, and the corresponding ARGs were detected in the colonies grown on the plates. However, using an antimicrobial susceptibility test, we found that ARGs delivered by OMVs were not persistent but only appeared transiently on the antibiotic-containing plates. Antibiotic resistance and ARGs were lost by the second bacterial passage.

https://journals.asm.org/doi/full/10.1128/spectrum.01379-22