犬链球菌感染:393例回顾性研究（4）

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

Discussion

讨论

The 3 most commonly isolated species of Streptococcus in this study were S canis, S dysgalactiae ssp equisimilis, and S equi ssp zooepidemicus. Infection with S canis or multiple Streptococcus spp was most likely to be associated with severe disease, including dermatitis, septicemia, placentitis, and pneumonia. Concurrent infection with other pathogenic bacteria, viruses, fungi, or parasites was common (267 of 393, 68%), especially in cases of dermatitis or pneumonia.

本研究中最常分离的3种链球菌为犬链球菌、似马停乳链球菌亚种和兽疫马链球菌亚种。犬链球菌或多种链球菌感染最可能与严重疾病相关，包括皮炎、败血症、胎盘炎和肺炎。同时感染其他细菌、病毒、真菌或寄生虫是常见的(267/393,68%)，特别是皮炎或肺炎病例。

Sex was not a risk factor. Fetuses and neonates were much more likely to have streptococcal infection than were other age groups; streptococcal organisms were isolated from all specimens in that age group. An annual trend was not detected, but streptococcal organisms were more commonly isolated in the summer. Confounding factors were not detected.

性别不是一个风险因素。胎儿和新生儿比其他年龄组更容易感染链球菌;从该年龄组的所有样本中分离出了链球菌。季节变化趋势不明显，但夏季分离链球菌较多。未发现混杂因素。

Streptococcal septicemia is one of the most common causes of fetal and neonatal death in the dog. In the present study, Streptococcus was isolated from all cultured fetal or neonatal specimens and was considered the cause of the abortion or neonatal death. Streptococcal infection should be highly considered in the differential diagnosis in cases of abortion or neonatal death in the dog. Histopathology and routine aerobic cultures are required to confirm infection.

链球菌败血症是犬胎儿和新生儿死亡的最常见原因之一。在本研究中，从所有培养的胎儿或新生儿样本中分离出链球菌，并被认为是导致流产或新生儿死亡的原因。流产或新生儿死亡的患犬病例的鉴别诊断应高度考虑链球菌感染。确诊感染需要组织病理学检查和常规有氧细菌培养。

As with people, a proportion of the canine population is a carrier of this opportunistic pathogen and does not develop clinical signs. Infection in utero or during passage through the vagina poses a great risk to the canine fetus. Septicemia and death typically occur in the first week of life. Consumption of contaminated milk is another possible but less likely source of infection.

与人一样，有一部分犬是这种条件性致病菌的携带者，不会出现临床症状。在子宫内或通过阴道时感染，对犬胎儿造成很大的危险。败血症和死亡通常发生在出生后第一周。另一种可能是食用受污染的牛奶，但不太可能是感染源。

Spread from the vagina, where several species of Streptococcus can reside in healthy individuals, to the uterus can result in endometritis or metritis with subsequent extension to the placenta. In the present study, streptococcal infection was a rare cause of placentitis. Neonatal streptococcal septicemia can also develop secondary to omphalophlebitis; however, omphalophlebitis was not detected in the present study.

链球菌可寄居于健康人的阴道内，由阴道扩散至子宫可导致子宫内膜炎或子宫炎，并随后蔓延至胎盘。在本研究中，链球菌感染是引起胎盘炎的罕见原因。新生儿链球菌败血症也可继发于脐静脉炎;然而，在本研究中未发现脐静脉炎。

Streptococcal septicemia in older dogs is often a sequel to localized infections, such as with necrotizing fasciitis. In the present study, streptococcal infection was associated with septicemia in only 13 of 1,728 cultured specimens from dogs older than 1 year. This indicates that streptococcal septicemia in the adult dog is relatively rare. Once the circulation has been seeded, the infection can spread to visceral organs—particularly, the heart, as well as the brain and the joints. Streptococcal infection is the most common cause of valvular endocarditis in the dog, and it typically affects the mitral valve.Concurrent polyarthritis in these dogs is common.Streptococcal infection in the brain and spinal cord can present as a parenchymal or subdural abscess, as a more diffuse inflammation (eg, meningoencephalitis), or as diskospondylitis.

老年犬的链球菌败血症通常是局部感染导致的，如坏死性筋膜炎。在本研究中，一岁以上犬的1728份培养样本中，只有13份链球菌感染与败血症相关。这说明在成年犬中链球菌败血症是相对少见的。一旦循环系统形成，感染就会扩散到内脏器官，尤其是心脏，以及大脑和关节。链球菌感染是犬心内膜炎最常见的原因，通常影响二尖瓣。并发性多关节炎在这些犬是常见的。脑和脊髓中的链球菌感染可表现为实质脓肿或硬膜下脓肿，也可表现为弥漫性炎症(如脑膜脑炎)或椎间盘脊柱炎。

Pulmonary streptococcal infection can present as bronchopneumonia or as a hemorrhagic form. In the present study, fetal/neonatal streptococcal bronchopneumonia was the most common presentation. Concurrent infection with other bacteria or viruses often complicates the histologic picture in streptococcal bronchopneumonia. Common copathogens include Bordetella spp, canine distemper virus, canine adenovirus 1 and 2, and canine herpes virus. Aerobic bacterial cultures and viral testing on lung samples are recommended in conjunction with histologic examination to confirm mixed infections. The hemorrhagic form of streptococcal pneumonia, which was rare in this study, can be devastating, with high morbidity and high mortality, particularly in kennel or shelter populations.

肺部链球菌感染可表现为支气管肺炎或出血性肺炎。在本研究中，胎儿/新生儿链球菌性支气管肺炎是最常见的表现。同时感染其他细菌或病毒往往使链球菌性支气管肺炎的组织学表现复杂化。常见的同时存在的病原体包括博代氏杆菌、犬瘟热病毒、犬瘟腺病毒1型和2型以及犬疱疹病毒。建议对肺部样本进行需氧细菌培养和病毒检测，结合组织学检查以确认混合感染。链球菌肺炎的出血性形式，在这项研究中是罕见的，可以是毁灭性的，高发病率和高死亡率，特别是在犬舍或收容所。

Necrotizing fasciitis is a severe, debilitating disease in adult dogs that can result in systemic illness and death. Although streptococcal dermatitis was common in this study, necrotizing fasciitis was relatively rare. Toxic shock–like syndrome, a typically fatal sequel of necrotizing fasciitis in dogs, resembles the toxic shock syndrome in people infected with S pyogenes. Affected dogs typically have intensely painful, deep dermal or subcutaneous lesions along the limbs or trunk. The skin commonly sloughs within 24 to 48 hours, and affected animals rapidly develop severe hypotensive shock and disseminated intravascular coagulation. Postmortem involvement of multiple organ systems suggests a period of septicemia before the development of this syndrome.

坏死性筋膜炎是一种严重的，使成年犬衰弱的疾病，可导致全身疾病和死亡。虽然链球菌性皮炎在本研究中很常见，但坏死性筋膜炎却相对罕见。中毒性休克样综合征，一种典型的犬坏死性筋膜炎的致命后遗症，类似于感染化脓性链球菌的人的中毒性休克综合征。患犬通常有强烈的疼痛，病变沿着四肢或躯干的真皮深层或皮下组织。皮肤通常在24 - 48小时内脱落，患病动物会迅速发展为严重的低血压休克和弥散性血管内凝血。死后剖检波及多器官系统，表明在该综合征发展之前有一段败血症期。

In dogs, S canis is the most common streptococcal species isolated in cases of toxic shock–like syndrome associated with necrotizing fasciitis. In people, the clonal expansion of invasive strains of S pyogenes is thought to promote the development of toxic shock syndrome. This does not appear to be the case in the dog. Furthermore, proteins from the strains of S canis isolated from cases of necrotizing fasciitis have homology with only 2 proteins (M protein and streptolysin O) of the 10 known virulence factors of invasive strains of S pyogenes. This finding suggests that other yet unknown factors are involved in the pathogenesis of S canis toxic shock–like syndrome in dogs.

在犬中，中毒性休克样综合征并发坏死性筋膜炎病例中，犬链球菌是最常分离的链球菌种类。在人身上，侵入性化脓性链球菌菌株的克隆扩增被认为促进了中毒性休克综合征的发展。但犬的情况似乎并非如此。此外，从坏死性筋膜炎病例中分离到的犬链球菌菌株的蛋白仅与入侵性化脓性链球菌菌株的10种已知毒力因子中的2种蛋白(M蛋白和链球菌溶血素O)同源。这一发现表明，犬的中毒性休克样综合征的发病机制还涉及其他未知因素。

People are most commonly infected with group A β-hemolytic streptococci, which include S pyogenes. Infection with group A β-hemolytic streptococci typically results in pharyngitis, although these organisms cause more severe diseases, such as necrotizing fasciitis and toxic shock syndrome. Group A β-hemolytic streptococcal infections most commonly occur from direct spread between people. Although group A β-hemolytic streptococci can be isolated transiently from the nasopharynx of household pets, dogs are not considered to be a significant source of infection.

人最常感染A组的β-溶血型链球菌，其中包括化脓性链球菌。感染A组的β-溶血型链球菌通常会导致咽炎，但这些微生物会导致更严重的疾病，如坏死性筋膜炎和中毒性休克综合征。A组的β-溶血型链球菌感染最常发生于人与人之间的直接传播。虽然A组β-溶血型链球菌可从家庭宠物的鼻咽部短暂分离，但并不被认为犬是一个重要的感染源。

In contrast, dogs commonly harbor group G β-hemolytic streptococci, which can spread from dogs to people via skin-to-skin contact as well as through bite wounds, especially if the person is immune compromised. S canis is the group G β-hemolytic Streptococcus most commonly associated with zoonotic infections between dogs and people. In people, S canis infection can result in septicemia, localized soft tissue infection, urinary tract infections, and osteomyelitis.

相反，犬身上通常携带有G组的β-溶血型链球菌，这种链球菌可以通过皮肤接触和咬伤从犬身上传播给人，特别是当人的免疫低下时。犬链球菌是一种G组β-溶血型链球菌，常与犬和人之间的人畜共患传染病有关。在人中，感染犬链球菌可导致败血症、局部软组织感染、尿路感染和骨髓炎。

Streptococcal infection has also been associated with cholangiohepatitis, keratitis, prostatic abscesses, perianal fistulas, and mastitis in dogs, as well as with urinary tract infections in the adult dog. In the present study, these disease processes were rarely reported with streptococcal infection. Free-catch urine samples can be contaminated by the normal flora inhabiting the mucosa of the external genitalia or vaginal vestibule. However, isolation of streptococcal organisms from a urine sample collected by cystocentesis or from kidney is likely clinically significant.

链球菌感染也与犬的胆管肝炎、角膜炎、前列腺脓肿、肛周瘘和乳腺炎有关，也与成年犬的尿路感染有关。在本研究中，这些疾病过程很少报道链球菌感染。自由采集的尿液样本可能被常驻在外生殖器粘膜或阴道前庭的正常菌群污染。然而，经膀胱穿刺或经肾脏收集的尿液样本中分离链球菌可能具有临床意义。

In the present study, streptococcal organisms were cultured from the skin and intestine but were rarely associated with disease in these organ systems. Streptococcus spp can reside on the skin and in the gastrointestinal tract of clinically healthy dogs and can be cultured from the conjunctiva, ears, external genitalia, intestine, feces, skin, oral cavity, and upper respiratory tract. Therefore, cultures of the skin, ears, and intestine should be interpreted in the context of clinical signs and pathologic findings. Streptococci are probably cultured incidentally or are secondary opportunistic invaders in most dogs with otitis or enteritis.

在本研究中，从皮肤和肠道培养有链球菌，但很少与这些器官系统的疾病相关。链球菌可常驻于临床健康犬的皮肤和胃肠道，可从结膜、耳道、外生殖器、肠道、粪便、皮肤、口腔、上呼吸道培养出。因此，皮肤、耳道和肠道的培养应根据临床症状和病理结果来解释。大多数耳炎或肠炎患犬中，链球菌可能是顺便培养出的，或继发性条件性致病菌。

In summary, streptococci are important opportunistic pathogens in the neonatal and adult dog. S canis, S dysgalactiae ssp equisimilis, and S equi ssp zooepidemicus are the most common pathogenic species in the dog. Streptococcal infection can result in septicemia as well as life-threatening localized infections in the skin and lung. Although streptococcal infection can cause disease in dogs, these organisms are a component of the normal flora of the skin and gastrointestinal tract. Thus, isolation of Streptococcus does not necessarily correlate with disease and must be interpreted with consideration of clinical and pathologic findings.

综上所述，链球菌是新生儿和成年犬中重要的条件致病菌。犬链球菌、似马停乳链球菌亚种和兽疫马链球菌亚种是犬中最常见的致病菌种。皮肤和肺部局部链球菌感染可导致败血症以及危及生命。虽然链球菌感染会导致犬患病，但这些微生物是皮肤和胃肠道正常菌群的组成部分。因此，链球菌的分离并不一定与疾病相关，必须结合临床和病理结果。

笼中红细胞

宠壹生

红蓝紫

南海

zhangenzyme

秘鸢

2heiyanquan

笼中红细胞

好文章。

廊坊永鑫罗玄

学习了。