一例湖羊纤维素性肺炎的病理组织学观察

为探究四川省某养殖场湖羊患病情况,以1只发病湖羊为例,研究观察病羊临床症状、解剖变化,采用H.E.染色方法分析病羊实质器官病理组织学变化,并从病羊中分离出菌株Z-1,采用生理生化、16S rDNA基因测序对其鉴定,采用腹腔注射对菌株Z-1进行动物回感试验,纸片扩散法对菌株Z-1进行药敏分析。结果表明:患病羊病症有高热、剧烈咳嗽并伴有喘气,口鼻周围可见黄色浓稠分泌物;解剖变化为多个实质器官明显肿大、充血,肺脏充血、颜色暗红,切开有血样泡沫状液体流出;病理组织切片可见肺、肝、脾等组织细胞肿胀、充血、出血,肺泡腔和细支气管中有大量粉红色纤维素性渗出物,炎性细胞浸润;菌株Z-1为革兰氏阳性菌,乳糖、七叶苷和山梨醇等生化反应呈阳性反应,木糖醇、甘露糖和蜜二糖等生化反应呈阴性反应;16S rDNA基因目的片段长度为1 428bp,与菌株NR_026471的相似性达到98%,综合鉴定为链球菌;动物回感试验表明该菌株对小鼠具有很强的致病性;药敏试验表明该菌株对氧氟沙星、诺氟沙星、环丙沙星和庆大霉素等敏感,对氨苄西林、青霉素和拉氧头孢等耐药。综上,该病湖羊患链球菌感染的纤维素性肺炎。

Histopathological observation of fibrinous pneumonia in Hu sheep

In order to investigate the pathogeny of Hu sheep in a farm of Sichuan Province, one affected Hu sheep was taken as the study case and its clinical symptoms and anatomical changes of diseased sheep were observed. The pathological changes of the parenchymal organs were analyzed by H. E. staining. Strain Z-1 was isolated from diseased sheep and identified by physiological and biochemical methods and 16S rDNA gene sequencing. The strain Z-1 was analyzed by animal feedback experiment and drug sensitivity test. The results showed that the sick sheep had high fever, severe cough and panting. Yellow thick secretions were observed around its mouth and nose. The anatomical changes displayed the tumefaction and congestion of multiple parenchymal organs including congestion of the lungs, dark red color, and bloody foamy fluid flowing out of the incision. The pathological tissue sections showed swelling, congestion, and bleeding of tissue cells such as lung, liver, and spleen; There were a large number of pink cellulose exudates and inflammatory cells in the alveolar space and bronchiole. The strain Z-1 was confirmed to be gram-positive bacteria. Its biochemical reactions to lactose, aescoside and sorbitol were positive, while reactions to newtol, mannose and melibiose were negative. The length of the target fragment of 16S rDNA gene was 1 428 bp, and its similarity with NR_026471 reached 98%. Therefore, it was comprehensively identified as Streptococcus. The animal feedback experiment displayed that the strain had strong pathogenicity to mice. The drug sensitivity tests showed that the bacterium was sensitive to ofloxacin, norfloxacin, ciprofloxacin and gentamicin, and resistant to ampicillin, penicillin and moxalactam. In summary, the diseased Hu sheep was suffered from Streptococcus infection of fibrinous pneumonia.