犬链球菌感染:393例回顾性研究（1） - 宠医帮

Streptococcus spp are opportunistic pathogens that normally reside in the upper respiratory, intestinal, lower urinary, and genital tracts but can cause localized infection or septicemia in dogs of all ages. A retrospective study of streptococcal infection in 393 dogs was conducted to identify the species of Streptococcus isolated, determine demographics of affected dogs, and characterize the disease processes associated with infection. The major streptococcal species isolated were S canis (88 cases, 22.4%), S dysgalactiae ssp equisimilis (13, 3.3%), and S equi ssp zooepidemicus (4, 1.0%). Sex was not a risk factor (P > .30). Fetuses and neonates were more likely to have streptococcal infection than were other age groups (P < .001). Streptococcal septicemia was considered an important cause of abortion and neonatal death and was isolated from all samples submitted for aerobic culture from dogs in that age group. There was a seasonal trend, with dogs more likely to have streptococcal infection in summer months. In dogs for which a disease process was identified, streptococcal infection was associated with dermatitis (29 dogs), pneumonia (24 dogs), adult septicemia (13 dogs), and fetal/neonatal septicemia leading to abortion or neonatal death (16 dogs). Identification of other clinically significant bacterial, viral, fungal, and parasitic organisms was common (267 of 393 dogs, 68%), especially in dogs with dermatitis or pneumonia. Infection with Streptococcus spp should be considered in the differential diagnosis in cases of abortion, septicemia, dermatitis, and pneumonia in dogs. Clinical significance of isolation of streptococcal organisms should be interpreted in context of clinical signs and pathologic findings.

链球菌是一种条件致病菌，通常存在于上呼吸道、肠道、下泌尿道和生殖道，但可以在所有年龄的犬身上引起局部感染或败血症。我们对393只犬进行了链球菌感染的回顾性研究，以鉴定分离出的链球菌种类，确定患犬统计数据，并描述与感染相关的疾病过程。分离到的链球菌主要为犬链球菌(88例，22.4%)、似马停乳链球菌亚种(13例，3.3%)和兽疫马链球菌亚种(4例，1.0%)。性别不是危险因素(P＞0.30)。胎儿和新生儿比其他年龄组更容易发生链球菌感染(P＜0.001)。链球菌败血症被认为是流产和新生儿死亡的一个重要原因，并从该年龄组所有提交进行有氧培养的犬的样本中分离出来。有季节性趋势，犬在夏季更容易发生链球菌感染。在已确定疾病过程的犬中，链球菌感染与皮炎(29只)、肺炎(24只)、成犬败血症(13只)和导致流产或新生儿死亡的胎儿/新生儿败血症(16只)有关。其他具有临床意义的常见病原是细菌、病毒、真菌和寄生虫(267 / 393只犬，68%)，特别是在患有皮炎或肺炎的犬。在犬的流产、败血症、皮炎和肺炎的鉴别诊断中应考虑链球菌感染。链球菌分离的临床意义应根据临床症状和病理结果来解释。

Streptococcus spp are gram-positive bacterial cocci that often appear in pairs or chains in routine Gram stains, cytologic preparations, and histologic sections. Streptococcus spp are easily cultivated, catalase negative, and facultative to strict anaerobes that are categorized on the basis of their hemolytic pattern on blood agar as α-hemolytic, β-hemolytic, or γ-hemolytic (nonhemolytic). In general, α-hemolytic and γ-hemolytic streptococci are normal inhabitants of the upper respiratory and lower urogenital tracts. Species of β-hemolytic Streptococcus are typically pathogenic. However, some pathogenic species, such as S agalactiae, have variable hemolytic patterns. Some species can be categorized into alphabetically designated Lancefield groups based on cell wall polysaccharides (C-substance), if present. Pathogenic species of Streptococcus in dogs are usually in Lancefield groups B, C, D, or G.

链球菌是革兰氏阳性球菌，常成对或成链出现在常规革兰氏染色、细胞学制剂和组织学切片中。链球菌很容易培养，过氧化氢酶阴性，根据它们在血琼脂上的溶血模式，即α-溶血型、β-溶血型或γ-溶血型(非溶血)，分为兼性到绝对厌氧。一般来说，α-溶血型和溶血性g型链球菌是上呼吸道和下泌尿生殖道的正常常驻微生物。β-溶血型链球菌通常具有致病性。然而，一些致病菌，如无乳链球菌，有不同的溶血模式。一些物种可以根据细胞壁多糖(c物质)，如果存在的话，按指定的Lancefield组字母顺序分类。犬链球菌的致病种通常为Lancefield组的B、C、D或G组。

Streptococcus spp are common opportunistic pathogens of mammals and are associated with a variety of diseases affecting multiple organ systems. Streptococcal infection in dogs has been associated with abortion, pneumonia, septicemia, endocarditis, necrotizing fasciitis, keratitis, lower urinary tract infections, cholangiohepatitis, arthritis, and meningoencephalitis. The purpose of this study was to review the major Streptococcus species isolated, the demographic data, and the associated diseases in 393 dogs with streptococcal infection.

链球菌是哺乳动物常见的条件致病菌，与各种影响多器官系统的疾病有关。犬的链球菌感染与流产、肺炎、败血症、心内膜炎、坏死性筋膜炎、角膜炎、下泌尿道感染、胆管性肝炎、关节炎和脑膜脑炎有关。本研究的目的是对393只感染链球菌的犬的分离链球菌的主要种类、病例数据统计和相关疾病进行综述。

The database at the Oklahoma Animal Disease Diagnostic Laboratory (OADDL) at Oklahoma StatUniversity was searched from August 2005 through April 2008 for any specimen from a domestic dog in which Streptococcus spp were cultured from tissues submitted to OADDL or from tissues harvested at necropsy at OADDL. Cases with isolation of Enterococcus spp or α-hemolytic Streptococcus spp that were not further speciated were excluded.

从2005年8月到2008年4月，研究人员在俄克拉荷马州立大学的俄克拉荷马动物疾病诊断实验室(OADDL)的数据库中，从提交给OADDL的组织或OADDL的尸检中采集的组织中，搜索了所有培养链球菌的家养犬样本。排除肠球菌病例，或未做更多特异性鉴定的α-溶血型链球菌病例。

The following information was tabulated from case records: age, sex, month and year of submission, sample type, species of Streptococcus, pathological diagnosis, and other infectious or neoplastic diseases. Streptococcus speciation was based on hemolytic pattern, biochemical reactions, and Lancefield groupings. Dogs were grouped by age as fetus/neonate (< 1 week), puppy (1 to 8 weeks), juvenile (9 weeks to 1 year), adult (1 to 8 years), and geriatric (> 8 years). Seasons were defined as winter (December, January, and February), spring (March, April, and May), summer (June, July, and August), or fall (September, October, and November).

从病例记录中列出以下信息:年龄、性别、提交月份和年份、样本类型、链球菌种类、病理诊断和其他感染性或肿瘤性疾病。链球菌形成种类基于溶血模式、生化反应和Lancefield分组。犬按年龄分组为胎儿/新生儿(＜1周）、幼犬(1 - 8周)、青年犬(9周至1岁)、成年犬(1 - 8岁)和老年犬(＞8岁)。季节分为冬季(12月、1月和2月)、春季(3月、4月和5月)、夏季(6月、7月和8月)或秋季(9月、10月和11月)。

All canine tissues submitted to the OADDL for bacterial culture were tabulated by year, month, sex, age, and tissue type. These numbers were used for statistical analysis to determine if sex or age were risk factors for bacterial infection or if there were annual or seasonal trends. The same data, plus the bacterial species isolated and any associated disease, were tabulated for those cases with Streptococcus isolation. Streptococcus isolates were also categorized as pure cultures, mixed cultures with less pathogenic bacterial organisms, or mixed cultures with other clinically important bacterial, fungal, parasitic, or viral organisms.

所有提交给OADDL进行细菌培养的犬组织按年、月、性别、年龄和组织类型列出。这些数字被用于统计分析，以确定性别或年龄是否是细菌感染的危险因素，或者是否存在年度或季节性趋势。同样的数据，再加上分离出的细菌种类和任何相关的疾病，被制成了链球菌分离病例的表格。链球菌分离物也分为纯培养物、致病菌较少的混合培养物，或与其他临床重要的细菌、真菌、寄生虫或病毒微生物的混合培养物。

Demographic data and clinical associations were statistically evaluated using commercial software programs (Microsoft Office Excel 2007, Microsoft Corp, Redmond, WA; Epicalc 2000 1.02, Brixton Books, http://www.brixtonhealth.com/; SPSS 17.0.1, SPSS Inc, Chicago, IL). The proportion of dogs with isolation of Streptococcus spp from the total samples cultured was evaluated according to the age of dogs by calculating a chi-square test for linear trend and by calculating risk ratios and 95% confidence intervals. The proportion of samples that were positive for Streptococcus spp was evaluated with a chisquare test to assess possible associations with sex. The proportion of positive samples per year was evaluated with correlation and regression analyses. Raw data were analyzed, including data that were weighted according to the number of months in the partial years at the beginning and end of the study and the number of samples per year. The overall association of season with the proportion of positive samples was evaluated by chi-square test; pairwise comparisons of seasons were analyzed by critical ratio (Z) tests. A P value of less than .05 was considered statistically significant.

使用商业软件程序。通过计算卡方检验线性趋势，计算风险比和95%置信区间，根据犬龄评估链球菌分离犬占培养样本总数的比例。用方检验评估链球菌阳性样本的比例，以评估可能与性别有关。采用相关分析和回归分析评估每年阳性样本的比例。对原始数据进行分析，包括根据研究开始和结束的部分年份的月份数和每年的样本数加权得到的数据。用卡方检验评价季节与阳性样本比例的总体关系;季节的两两比较采用临界比(Z)检验。P值小于0.05被认为有统计学意义。