猪鼻支原体的分离鉴定及其对巴马猪的致病性试验

Isolation and identification of Mycoplasma hyorhinis strain and its pathogenicity in Bama pigs

为了探索猪鼻支原体（Mhr）对仔猪的致病性，从临床呼吸道疾病的患猪肺分离到1株猪鼻支原体流行菌株（Mhr—DL株）。对该菌株16SrRNA序列进行的分析证实，它与GenBank中的猪鼻支原体（AB680688）、猪肺炎支原体（NR-074745）和猪滑液支原体（KC512403）的同源性分别为99．3％、92．8％和74．0％。电镜下该菌为多形性，大小为500～600nm。取Mhr-DL菌株培养物（1．8×10^9 CCU／mL）经腹腔和气管途径接种SPF小型巴马猪，被感染猪临床上表现为精神沉郁、粪便干燥、食欲不振、结膜炎、体温高达41．6℃；剖检时病理表现为肺、肝、脾等器官纤维渗出，淋巴结充血肿胀、胸膜炎、腹膜炎、肺呈虾肉样病变。茵株核酸检测发现，肺和扁桃体检出率最高；组织病理表现为间质性肺炎，淋巴细胞增生、坏死、崩解，肾毛细血管淤血，小肠固有层大量嗜酸性粒细胞浸润、肠绒毛结构不完整，心脏小血管淤血，脾白髓内淋巴细胞增生。本研究获得的Mhr-DL菌株对巴马猪具有显著的致病性，为今后深入开展猪鼻支原体致病机理和防控技术的研究奠定了基础。

In order to explore the pathogenicity of Mycol）lasrna hyorhinis （Mhr） in piglets, a strain of M. hyorhinis from the lung of the clinical pigs with respiratory syndrome disease was isolated,and named as Mhr-DL strain. The 16 S rRNA gene of this strain was sequenced and the identity with M. hyorhinis （AB680688）,M. hyopneurnoniae（NR_074745） and M. hyosynoviae（KC512403） was 99. 3%, 92.8% and 74.0%,respectively. Under electron microscope, the bacteria was of polymorphism and 500--600 nm in size. To investigate the pathogenicity of Mhr-DL strain, SPF Bama pigs were used for experimental infec- tion. The pigs were inoculated by intraperitoneal or intratracheal injection with the isolate cultures （1. 8×109 CCU/mL）. The clinical ＇symptoms of the infected pigs showed that depression of spirit, dry feces, loss of appetite,stretch,conjunctivitis, and high body temperature more than 41. 6℃. The lesion gross showed that numerous of fibrous exudation existed in the lung, liver, spleen, stomach, greater omentum and ingui- nal lymph nodes, and the mesenteric lymph nodes exhibited hyperemia, pleurisy and peritonitis. Meat colorlike changes in the lung were also observed. The Mhr-DL nucleic acid positive rate in the lung and tonsil of