一起炭疽疫情中炭疽病原检测方法的应用与评价

Evaluation of the methods applied for the detection of Bacillus anthracis in anthrax outbreak

目的分析总结一起炭疽疫情中应急检测的经验与问题,为炭疽疾病预防控制提供参考依据。方法采集报告的疑似皮肤炭疽患者皮损渗出液和静脉血标本,与病例相关的病死动物和土壤标本,渗出液采集采用载玻片直接蘸取和无菌棉签擦取2种方法,用涂片镜检、直接分离培养和肉汤增菌后分离培养细菌以及炭疽芽胞杆菌毒力基因PCR扩增方法检测病原,分析检测结果。结果共采集标本57份,病例标本占91.23%,病死牛肉及剖牛处土壤标本占8.77%。病例标本采集时间距发病时间最短1d,最长23d,平均6.62d。29例疑似皮肤炭疽患者在采样时其中16例(占55.17%)已使用抗生素类药物治疗,4例(占13.79%)未曾使用抗生素。从2例未使用抗生素的患者皮损渗出液和1份病死牛肉中分离到炭疽芽胞杆菌,分离阳性率为5.26%;其中1例患者皮损渗出液涂片镜检阳性;全部标本PCR扩增结果均为阴性。结论标本炭疽芽胞杆菌阳性检出率较低,与采样方法和采样时机关系较大,应加强部门间的沟通协作和人群的健康教育,做到疫情早报告、早确诊、早控制。

Objective To analyze and summarize the experience and problems in emergent detection of Bacillus anthracis in anthrax outbreak for providing a basis for anthrax prevention and control. Methods The study collected lesions exudates and blood samples from suspected cases, as well as related animal samples and soil samples. The lesions were collected by slides and sterile cotton swabs. Smear microscopy, direct culture and broth enrichment were used to isolate and foster virulence genes. The virulence genes were amplified by PCR for detection of pathogens. Results Fifty-seven specimens were collected. 91.23% of the specimens came from B. anthracis cases and the other 8.77% came from cattle and soil. The time window between disease outbreak and collection of case specimens was 1 day at least and 23 days at most, with an average of 6.62 days. 16 （55.17%） of 29 suspected cases had received antibiotic treatment before their specimens were collected while 4 （13.79%） suspected cases had never received any antibiotic treatment. B. anthracis was isolated from lesions of 2 suspected cases who did not receive antibiotic treatment and 1 dead cattle, with 5.26% of positive isolation rate. Lesions from 1 patient had positive result under smear microscopy. All the specimens were tested negative after PCR amplification. Conclusion Low detection rate of B. anthracis is closely associated with the methods and time window of sample collection. Therefore, we should enhance interdepartmental communication and coordination and public education for early reporting, diagnosis and control of the pandemic.