犬链球菌感染:393例回顾性研究（3）

王帆

Streptococcal Infection in Dogs: A Retrospective Study of 393 Cases

犬链球菌感染:393例回顾性研究

G. Lamm1 , A. C. Ferguson1 , T. W. Lehenbauer2 , and B. C. Love1

翻译：王帆

Pathology

病理学

Of the 24 fetal and neonatal dogs cultured, 15 (62.5%) had streptococcal septicemia that resulted in abortion or neonatal death. Gross lesions were minimal. Histologically, colonies of cocci distended vascular lumina in multiple organs (Figs. 1, 2). Inflammation and necrosis of the vascular wall and surrounding tissues was also seen. Placentitis was noted in 2 cases. Interestingly, septicemia was not diagnosed in dogs between 1 week and 1 year of age. Streptococcal infection was associated with septicemia in 13 dogs older than 1 year. Endocarditis and encephalitis were sequela of streptococcal septicemia in adult dogs. In cases of endocarditis, the wall of the affected valve was irregularly thickened and mottled dark red (Fig. 3). Histologically, the valve was markedly expanded by fibrin, cellular debris, and numerous neutrophils (Fig. 4). Neutrophils and fibrin adhered to the surface. In cases of encephalitis, numerous neutrophils mixed with fibrin and fewer macrophages, lymphocytes, and plasma cells markedly expanded the meninges and Virchow–Robin space.The inflammation was focally severe, forming space-occupying lesions that effaced the neuropil and penetrated the ventricles (Figs. 5, 6).

在培养的24只胎儿和新生儿犬中，15只(62.5%)发生链球菌败血症，导致流产或新生儿死亡。肉眼可见病变最轻。组织学上，在多个器官中，球菌菌落使血管腔扩张(图1、2)。血管壁和周围组织也出现炎症和坏死。2例出现胎盘炎。有趣的是，在1周至1岁之间的犬没有被诊断出败血症。13只年龄大于1岁的犬的链球菌感染与败血症有关。心内膜炎和脑炎是成年犬链球菌败血症的后遗症。在心内膜炎病例中，瓣膜壁不规则增厚，呈斑驳暗红色(图3)。组织学上，由于纤维蛋白、细胞碎片和大量中性粒细胞，瓣膜明显扩张(图4)。中性粒细胞和纤维蛋白粘附在瓣膜表面。脑炎病例中，大量中性粒细胞混合着纤维蛋白、少量巨噬细胞、淋巴细胞和浆细胞，脑膜和Virchow-Robin间隙明显扩大。炎症呈局部严重，形成占位性病变，使神经纤维网消失并穿透脑室(图5,6)。

Pulmonary streptococcal infection appeared as bronchopneumonia or a hemorrhagic form. Bronchopneumonia was associated with streptococcal infection in 7 neonates and 17 dogs older than 1 week of age. Affected dogs developed severe pneumonia characterized by pulmonary consolidation (Fig. 7). Histologically, numerous neutrophils flooded the bronchial, bronchiolar, and alveolar spaces, obliterating the adjacent architecture (Fig. 8). In more severely affected areas, the neutrophils were admixed with necrotic cellular debris and fibrin. Microcolonies of cocci were frequent. The hemorrhagic form was associated with streptococcal infection in 2 dogs between 1 and 8 years of age. Affected dogs had dark red, wet, rubbery lungs that oozed copious blood on section. Histologically, alveolar spaces were flooded with erythrocytes and variable numbers of neutrophils admixed with fibrin. Colonies of cocci were rarely present within capillaries or pneumonic parenchyma.

肺部链球菌感染表现为支气管肺炎或出血性肺炎。7例新生儿和17只1岁以上的犬发生与链球菌感染相关的支气管肺炎。患犬出现以肺实变为特征的严重肺炎(图7)。组织学上，大量中性粒细胞充斥支气管、细支气管和肺泡间隙，使相邻的结构消失(图8)。在较严重的病变区，中性粒细胞与坏死的细胞碎片和纤维蛋白混合。常见小的球菌菌落。在2只1至8岁的犬身上发现了与链球菌感染有关的出血性形式。患犬的肺呈暗红色、潮湿、肺部橡胶样，在切片上渗出大量血液。组织学上，肺泡腔充满红细胞和数量不等的中性粒细胞混杂着纤维蛋白。球菌菌落很少出现在毛细血管或肺实质内。

Streptococcus was isolated from 32 of the 187 samples of skin or hair. Associated dermatitis was documented in only 29 of these dogs, all of which were > 1 year of age. Only 2 had necrotizing fasciitis. Grossly, dogs with necrotizing fasciitis had regionally extensive alopecia. The affected epidermis was moist, red, and occasionally ulcerated (Fig. 9). Underlying dermis and subcutis were effaced by cavitations filled with clumped, red to brown material. Histologically, there was liquefactive necrosis of the dermis and subcutis (Fig. 10). Hemorrhage was common, as was infiltration by numerous neutrophils with fibrin and cellular debris. The presence of bacterial microcolonies was variable. Regional vasculitis was also seen (Fig. 11). Necrotizing fasciitis resulted in secondary septicemia and toxic shock–like syndrome in 1 dog, which had infarcts in multiple organs, including the tongue, spleen, and kidney (Fig. 12).

从187份皮肤或毛发样本中分离出32份链球菌。在这些犬中只记录29只与之相关的皮炎，所有的都是＞1岁。只有2只患有坏死性筋膜炎。坏死性筋膜炎患犬有局部大面积脱毛。病变部位表皮潮湿、发红，偶见溃疡(图9)。真皮和皮下组织结构消失，充气、有发红至棕色物质。组织学上，真皮和皮下组织出现液化性坏死(图10)。常见出血，大量中性粒细胞伴有纤维蛋白和细胞碎片浸润。细菌菌落数量不等。也可见局部血管炎(图11)。1只犬的坏死性筋膜炎导致继发败血症和中毒性休克样综合征，导致多个器官梗死，包括舌头、脾脏和肾脏(图12)。

Streptococcus species were isolated from 5 of 22 liver or bile samples: 1 such isolate was from a dog with hepatitis; 2 were from dogs with septicemia; in the other 3 cases, no disease process was identified in the report.

从22份肝脏或胆汁样本中分离出5种链球菌:1份来自肝炎患犬;2例来自败血症患犬;在其他3例报告中，未明确疾病过程。

Streptococcus was isolated from 54 of the 196 ear swabs from dogs. The significance of streptococcal infection in the development of otitis in these dogs is not known, because clinical information or samples for histopathology were not provided. Isolation of other organisms, such as Pseudomonas spp, Malassezia spp, and Proteus spp, was considered to be clinically significant in most cases of otitis.

196份犬耳拭子中有54份分离出链球菌。链球菌感染在这些犬的耳炎发展中的意义尚不清楚，因为没有提供临床信息或组织病理学样本。分离的其他微生物，如假单胞菌、马拉色菌和变形杆菌，被认为在大多数耳炎病例中具有临床意义。

Streptococcus was isolated from 122 of 244 samples of the gastrointestinal tract or feces. Of these 122 dogs, enteritis was documented in 73. However, it is unlikely that streptococcal infection was a primary cause of enteritis in any of these dogs. Overgrowth of streptococcal organisms may have followed infection with a primary intestinal pathogen, such as canine parvovirus 2, Clostridium spp, Salmonella spp, and/or b-hemolytic Escherichia coli. Canine parvovirus 2 infection was the most common primary infection in dogs in this study.

244份胃肠道或粪便样本中检出122份链球菌。在这122只犬中，73只是肠炎。然而，链球菌感染不太可能是这些犬肠炎的主要原因。链球菌微生物的过度生长可能是由于感染了主要肠道病原微生物，如犬细小病毒2型、梭状芽孢杆菌、沙门氏菌和/或β-溶血型大肠杆菌。犬细小病毒2型感染是本研究中最常见的犬原发性感染。

Species of Streptococcus were isolated from 10 of 35 male reproductive tract samples, 5 of 23 ocular or periocular samples, 26 of 804 urine or lower urinary tract samples, and 2 of 12 kidney samples. However, isolation was not associated with disease in any of these cases, because of incomplete clinical histories or lack of samples for histologic examination. Streptococcus spp were not isolated from any of the 7 mammary tissue or milk samples from dogs with mastitis.

从35例雄性生殖道样本中分离出10例链球菌，从23例眼部或眼周样本中分离出5例链球菌，从804例尿液或下泌尿道样本中分离出26例链球菌，从12例肾样本中分离出2例链球菌。然而，在这些病例中，由于临床病史不完整或缺乏组织学检查样本，链球菌的分离与疾病无相关性。7例乳腺炎犬乳腺组织或乳汁样本均未分离到链球菌。

Figure 1. Liver; neonatal dog with streptococcal septicemia; dog No. 1. Microcolonies of bacterial cocci fill the sinusoids (arrows). The surrounding hepatocytes are degenerate and necrotic (arrowheads). HE. Inset: High magnification of bacterial microcolonies. Figure 2. Lung; neonatal dog with streptococcal septicemia; dog No. 1. Bacterial cocci distend alveolar capillaries (arrows). The surrounding architecture is obscured by cellular debris and fibrin. HE. Figure 3. Heart; streptococcal valvular endocarditis in an adult dog; dog No. 2. The aortic valve and left atrioventricular valve are markedly thickened and irregular (arrows). The inflammation extends to the underlying septum, resulting in a communication between the left and right ventricles. Figure 4. Heart; streptococcal valvular endocarditis in an adult dog; dog No. 2. The valvular architecture is effaced by neutrophils mixed with cellular debris and fibrin (arrow). HE. Inset: High magnification of bacterial microcolonies in cellular debris. Figure 5. Brain; streptococcal encephalitis in an adult dog; dog No. 3. Numerous neutrophils are mixed with fibrin and cellular debris. HE. Figure 6. Brain; streptococcal ventriculitis in an adult dog; dog No. 3. Neutrophils, macrophages, and cellular debris flood the ventricle and surround microcolonies of bacterial cocci (arrow). The arrowhead marks the ependymal lining. HE.

图1。肝脏;新生儿犬患链球菌败血症;1号犬：肝窦内充满小的细菌菌落(箭)。周围肝细胞退化和坏死(箭头)。HE染色。插图:放大的细菌菌落。

图2。肺脏;新生儿犬患链球菌败血症;1号犬：球菌使肺泡毛细血管扩张(箭)。细胞碎片和纤维蛋白使周围组织结构消失。HE染色。

图3。心脏;一只成年犬患链球菌心内膜炎；2号犬：主动脉瓣和左房室瓣明显增厚和不规则(箭)。炎症扩展到隔膜，导致左心室和右心室之间相通。

图4。心脏;一只成年犬患链球菌心内膜炎；2号犬：中性粒细胞伴有细胞碎片和纤维蛋白(箭)使瓣膜结构消失。HE染色。插图:放大的细胞碎片中的细菌菌落。

图5。大脑;一只成年犬患链球菌性脑炎;3号犬：大量中性粒细胞伴有纤维蛋白和细胞碎片。HE染色。

图6。大脑;一只成年犬患链球菌脑室炎;3号犬：中性粒细胞、巨噬细胞和细胞碎片充斥心室，周围有小的球菌菌落(箭)。箭头表示室管膜内皮。HE染色。

Figure 7. Lung; streptococcal pneumonia in a puppy; dog No. 4. Extensive pulmonary consolidation appears as coalescing dark red areas in all lobes. Figure 8. Lung; streptococcal bronchopneumonia in a puppy; dog No. 5. Bacterial cocci are mixed with fibrin, macrophages, and cellular debris in alveolar spaces (arrow). A basophilic intranuclear (adenoviral) inclusion (large arrowhead) and eosinophilic cytoplasmic (canine distemper viral) inclusions (small arrowheads) are in macrophages and bronchiolar epithelial cells. HE. Figure 9. Haired skin; streptococcal necrotizing fasciitis in an adult dog; dog No. 2. Affected skin is erythemic with alopecia, ulceration, and dark blue patches of hemorrhagic necrosis. Figure 10. Panniculus; streptococcal necrotizing fasciitis in an adult dog; dog No. 2. There is necrosis of the subcutis with hemorrhage and bacterial colonies (arrow). The asterisk marks a large central cavity in the panniculus. HE. Inset: Higher magnification of the bacterial microcolonies. Figure 11. Panniculus; streptococcal necrotizing fasciitis in an adult dog; dog No. 2. There is inflammation within the wall of a vessel. HE. Figure 12. Tongue; streptococcal toxic shock–like syndrome in an adult dog; dog No. 2. Note the infarct along the lateral margin (arrow).

图7。肺脏;一只幼犬患链球菌肺炎;4号犬：大面积肺实变，所有肺叶暗红色区域联合。图8。肺脏;一只幼犬患链球菌性支气管肺炎;5号犬：球菌与纤维蛋白、巨噬细胞和肺泡腔内的细胞碎片混合(箭)。巨噬细胞和细支气管上皮细胞内的细胞核内的嗜碱性(腺病毒)包涵体(大箭头)和嗜酸性细胞质(犬瘟热病毒)包涵体(小箭头)。HE染色。

图9。有毛皮肤;一只成年犬患链球菌坏死性筋膜炎;2号犬：病变皮肤红斑，伴有脱毛、溃疡和深蓝色出血性坏死斑。

图10。脂膜;一只成年犬患链球菌坏死性筋膜炎;2号犬：皮下组织坏死伴出血和细菌菌落(箭)。星号表示在脂膜中有一个大空腔。HE染色。插图:放大的细菌菌落。

图11。脂膜;一只成年犬患链球菌坏死性筋膜炎;2号犬：血管壁有炎症反应。HE染色。

图12。舌部;一只成年犬患链球菌中毒性休克样综合征;2号犬：注意沿侧边的梗死灶(箭)。