Sayan Murat, Erdenliğ Sevil, Etiler Nilay
Kocaeli University Faculty of Medicine, Kocaeli, Turkey.
Mikrobiyol Bul. 2011 Oct;45(4):655-63.
Canine brucellosis which is due to Brucella canis, is transmitted to man by infected dogs or their secretions. The symptoms of canine brucellosis are similar to the symptoms of brucellosis caused by other Brucella species and endocarditis or meningitis may develop in untreated cases. There is limited data regarding B.canis infections in man and the current status of the disease is insufficiently evaluated in our country. Serological diagnosis of brucellosis is classically based on standard slide and tube agglutination tests. However, the antigens used in these tests detect antibodies that develop against species (B.melitensis, B.abortus, B.suis) with "smooth" lipopolysaccharides in their cell wall. B.canis has "rough" lipopolysaccharide in its cell wall and thus these classical tests can not detect antibodies against B.canis. Besides there is no commercial slide agglutination test which uses B.canis antigens. The aim of this study was to investigate the B.canis seropositivity by slide agglutination test (SAT), using homemade B.canis antigen, in healthy subjects and to determine the prevalence of B.canis infection in our population. A total of 1930 blood donors (age range: 18-55 years) who were admitted to the blood donation centers of different hospitals in Kocaeli province (located at Northwestern part of Turkey) between January-December 2010, have been included in the study. All of the subjects were negative in terms of Rose-Bengal plate test (B.abortus antigen test). Undiluted serum samples were initially screened by SAT, and those which were found positive were retested by SAT in the dilutions of 1/25 - 1/200. Confirmation of the positive results was performed by using 2-mercaptoethanol (2-ME) SAT. The test antigen (Alton antigen) was prepared from the less mucoid M(-) variant of B.canis, and 1/1048 titered dog antiserum was used as positive control. Of the 1930 blood donors sera, 40 (2.1%) were found positive with SAT, whereas 16 of them yielded equivocal positive (12 were 1/50, 4 were 1/100 titers) and 15 yielded positive (≥ 1/200 titer) results with 2-ME SAT. As a result, B.canis seropositivity rate in the healthy subjects in this study was estimated as 1.6% (31/1930). The integration of B.canis SAT to the routine serological tests applied for brucellosis diagnosis might aid to the data related to brucellosis epidemiology. B.canis seroprevalence determined as 1.6% in this study supplied a basic data about the infection in our country. However, larger scale, multicenter studies with different patient and risk groups should be conducted to further evaluate the epidemiology of B.canis infections in Turkey.
犬布鲁氏菌病由犬布鲁氏菌引起，通过感染的犬只或其分泌物传染给人类。犬布鲁氏菌病的症状与其他布鲁氏菌属引起的布鲁氏菌病症状相似，未经治疗的病例可能会发展为心内膜炎或脑膜炎。关于人类感染犬布鲁氏菌的资料有限，我国对该疾病的现状评估不足。布鲁氏菌病的血清学诊断传统上基于标准玻片和试管凝集试验。然而，这些试验中使用的抗原检测的是针对细胞壁中含有“光滑”脂多糖的菌种（羊种布鲁氏菌、牛种布鲁氏菌、猪种布鲁氏菌）产生的抗体。犬布鲁氏菌的细胞壁含有“粗糙”脂多糖，因此这些传统试验无法检测到针对犬布鲁氏菌的抗体。此外，没有使用犬布鲁氏菌抗原的商业玻片凝集试验。本研究的目的是使用自制的犬布鲁氏菌抗原，通过玻片凝集试验（SAT）调查健康受试者中犬布鲁氏菌的血清阳性率，并确定我国人群中犬布鲁氏菌感染的患病率。2010年1月至12月期间，共有1930名年龄在18至55岁之间、前往科贾埃利省（位于土耳其西北部）不同医院献血中心献血的人纳入本研究。所有受试者的虎红平板试验（牛种布鲁氏菌抗原试验）均为阴性。未稀释的血清样本首先通过SAT进行筛查，发现阳性的样本再用SAT在1/25至1/200的稀释度下重新检测。阳性结果通过使用2-巯基乙醇（2-ME）SAT进行确认。试验抗原（奥尔顿抗原）由犬布鲁氏菌的粘液较少的M（-）变体制备，1/1048效价的犬抗血清用作阳性对照。在1930份献血者血清中，40份（2.1%）通过SAT检测为阳性，其中16份产生可疑阳性结果（12份为1/50效价，4份为1/100效价），15份通过2-ME SAT检测为阳性（≥1/200效价）。结果，本研究中健康受试者的犬布鲁氏菌血清阳性率估计为1.6%（31/1930）。将犬布鲁氏菌SAT纳入用于布鲁氏菌病诊断的常规血清学检测中，可能有助于获取与布鲁氏菌病流行病学相关的数据。本研究确定的犬布鲁氏菌血清阳性率为1.6%，提供了我国关于该感染的基础数据。然而，应开展更大规模、针对不同患者和风险群体的多中心研究，以进一步评估土耳其犬布鲁氏菌感染的流行病学情况。
