鸡源奇异变形杆菌分离鉴定及生物学特性

Isolation, identification and biological characteristics of a Proteus mirabilis from chicken

摘要:

[背景] 奇异变形杆菌（Proteus mirabilis，PM）是人畜共患病原菌，在自然界分布广泛。近年来，随着畜禽奇异变形杆菌病发病率上升和耐药性增强，亟需开展对该菌的防控研究。[目的] 分离鉴定鸡源奇异变形杆菌，鉴定其耐药性、致病性、生物被膜形成能力等生物学特性。[方法] 采用聚合酶链式反应（Polymerase Chain Reaction，PCR）方法鉴定了从2019-2020年病鸡中分离的52株临床奇异变形杆菌。分别采用药敏试验、PCR、结晶紫染色法对临床菌株的耐药性、毒力基因及生物膜的形成进行研究。[结果] 选择14株代表性菌株进行16S rRNA基因测序，结果表明所测分离菌株均为奇异变形杆菌。所有分离菌株均对克林霉素、阿奇霉素、红霉素、四环素和利福平耐药，对氯霉素和头孢曲松外的抗生素耐药性均高于50%。对分离的奇异变形杆菌的13个毒力基因检测表明，所有菌株均能检测到hpmA、hpmB、rpoA、mrpA、fliL、zapA、ureC、atfC、atfA、pmfA，而ucaA和rsbA检出率分别为19.23%（10/52）和48.08%（25/52），hlyA未检出。对分离株生物被膜形成能力检测结果表明，所有菌株均能形成生物被膜，19.23%（10/52）的分离菌株形成生物被膜能力强，而且25℃条件下成膜能力比37℃更强。[结论] 鸡源奇异变形杆菌携带多种毒力基因，具有较强生物被膜形成能力，耐药模式多样且日趋严重，应进一步加强对奇异变形杆菌在动物致病性和耐药性方面的监控，以降低其感染风险。

关键词:奇异变形杆菌;分离鉴定;耐药性;毒力基因;生物被膜

Abstract:

[Background] Proteus mirabilis (PM) is a zoonotic pathogen, which is widely distributed in environment. In recent years, diseases caused by PM and the drug tolerance to PM has gradually increased, raising the importance on the prevention and control of PM. [Objective] To isolate and identify PM from chicken, and to analyze its biological characteristics, such as drug resistance, pathogenicity, and biofilm formation ability. [Methods] Polymerase chain reaction (PCR) was used to identify 52 clinical PM strains which were isolated from sick chicken between 2019 and 2020. The drug resistance, virulence genes and biofilm formation of the clinical strains on PM were investigated by the drug-resistance phenotype, PCR, crystal violet staining method respectively. [Results] The results of 16S rRNA gene sequencing on 14 selected representative strains indicated that all the detected strains were PM. All isolates were resistant to clindamycin (CLDM), azithromycin (AZI), erythromycin (EM), tetracycline (TET) and rifampin (RFP), and the resistance rates of drugs other than chloramphenicol and ceftriaxone was higher than 50%. The results of detection of 13 virulence genes showed that all PM strains contained hpmA, hpmB, rpoA, mrpA, fliL, zapA, ureC, atfC, atfA and pmfA, while the detectable rates of ucaA, rsbA and hlyA were 19.23% (10/52), 48.08% (25/52) and 0.0% (0/52), respectively. The results of biofilm formation ability showed that all strains could form biofilm. 19.23% (10/52) of the isolates had strong ability of biofilm formation and the 25℃ temperature condition had stronger ability of biofilm formation than at 37℃. [Conclusion] PM from avian harbored various virulence genes, and had strong biofilm formation ability. The drug resistance to PM has increased significantly and resistance patterns were complex. It suggested that the tighter monitor on pathogenicity and drug resistance of PM should be carried out to reduce the risk of PM infection.

Key words:Proteus mirabilis;isolation and identification;drug resistance;virulence genes;biofilm