梅花鹿源奇异变形杆菌的分离鉴定及生物学特性

Isolation, identification, and characterization of sika deer-derived Proteus mirabilis

摘要:

【背景】奇异变形杆菌(Proteus mirabilis)是重要的人畜共患病病原，可引起梅花鹿仔鹿腹泻，给梅花鹿养殖业造成严重危害。【目的】鉴定引起吉林省某梅花鹿场仔鹿腹泻病的细菌性病原种类及其生物学特性，并确定该病原造成的主要病理特征。【方法】收集腹泻病空肠内容物，通过细菌分离培养、革兰氏染色、显微镜镜检、16S rRNA基因及atpD基因测序和进化树分析等方法鉴定细菌种类。采集腹泻鹿的空肠、肺、肝、脾、肾和心等组织样品制作病理切片。通过检测毒力基因、生物膜形成能力、耐药性与耐药基因，以及部分菌株的小鼠致病性分析该菌的生物学特性。【结果】共鉴定出3株奇异变形杆菌，分别命名为SKPM1、SKPM2、SKPM3。3株菌均携带ureC、zapA、atfC、atfA、rsbA、ucaA和pmfA等7种毒力基因，具有生物膜形成能力；3株菌对青霉素、头孢氨苄、庆大霉素、四环素、多黏菌素B等抗生素表现出多重耐药性，并检测出bla_TEM、bla_CTX-M、tetB、ant(3″)-I、sul2等耐药基因；致病性上菌株SKPM2的LD₅₀为3.98×10⁷ CFU/mL。【结论】本研究分离鉴定了3株梅花鹿源奇异变形杆菌，并研究了其生物学特性，为该菌引起的仔鹿腹泻病的防治和深入研究提供了实验基础。

Abstract:

[Background] Proteus mirabilis is a major zoonotic pathogen that can cause diarrhea of young sika deer (Cervus nippon), posing a serious threat to the sika deer farming industry. [Objective] To identify and characterize the bacterial pathogens and reveal the main pathological changes in the young sika deer suffering from diarrhea at a sika deer farm in Jilin. [Methods] We collected the jejunal contents of the young sika deer suffering from diarrhea, isolated the bacterial pathogens by the culture method, and identified the pathogens by Gram staining, microscopic examination, 16S rRNA and atpD sequencing, and phylogenetic analysis. In addition, we collected the jejunum, lung, liver, spleen, kidney, and heart samples from diarrheal sika deer to prepare pathological sections. The bacterial pathogens were characterized in terms of virulence genes, biofilm formation, antibiotic resistance, antibiotic resistance genes, and pathogenicity in mice.[Results] Three strains of P. mirabilis were identified and named SKPM1, SKPM2, and SKPM3, respectively. All of the three strains carried seven virulence genes (ureC, zapA, atfC, atfA, rsbA, ucaA, and pmfA) and could form biofilms. The three strains had resistance to multiple antibiotics including penicillin, cefalexin, gentamicin, tetracycline, and polymyxin B and carried resistance genes such as bla_TEM, bla_CTX-M, tetB, ant(3″)-I, and sul2. Strain SKPM2 showed the LD₅₀ of 3.98×10⁷ CFU/mL in mice. [Conclusion] We isolated and characterized three strains of P. mirabilis from sika deer. The findings provided an experimental basis for the prevention, treatment, and intensive research of the disease that caused by this bacterium in young deer.