Beijing Key Laboratory for Prevention and Control of Infectious Diseases in Livestock and Poultry, Institute of Animal Husbandry and Veterinary Medicine, Beijing Academy of Agriculture and Forestry Sciences, Beijing, 100097, China.
State Key Laboratory of Agricultural Microbiology, Division of Animal Infectious Disease, Huazhong Agricultural University, Wuhan, Hubei, 430070, China.
Vet Microbiol. 2021 Mar;254:109011. doi: 10.1016/j.vetmic.2021.109011. Epub 2021 Feb 6.
Glaesserella parasuis is the causative agent of Glässer's disease in swine. Serotyping plays an essential role in prevalence investigations and in the development of vaccination strategies for the prevention of this disease. Molecular serotyping based on variation within the capsule loci of the 15 serovars is more accurate and efficient than traditional serological serotyping. To reduce the running time and facilitate ease of data interpretation, we developed a simple and rapid cycle threshold (Ct) value-based real time PCR (qPCR) method for the identification and serotyping of G. parasuis. The qPCR method distinguished between all 15 serovar reference strains of G. parasuis with efficiency values ranging between 85.5 % and 110.4 % and, R values > 0.98. The qPCR serotyping was evaluated using 83 clinical isolates with 43 of the isolates having been previously assigned to a serovar by the gel immuno-diffusion (GID) assay and 40 non-typeable isolates. The qPCR results of 41/43 (95.3 %) isolates were concordant with the GID assay except two isolates of serovar 12 were assigned to serovar 5. In addition, the qPCR serotyping assigned a serovar to each of the 40 non-typeable isolates. Of the 83 isolates tested to assign a serovar, a concordance rate of 98.8 % (82/83) was determined between the qPCR and the previously reported multiplex PCR of Howell et al. (2015) (including those that were either serovars 5 or 12). Despite the inability to differentiate between serovars 5 and 12, the Ct value-based qPCR serotyping represents an attractive alternative to current molecular serotyping method for G. parasuis and could be used for both epidemiological monitoring and the guidance of vaccination programs.
副猪嗜血杆菌是猪格拉泽氏病的病原体。血清型鉴定在疾病的流行调查和疫苗接种策略的制定中起着至关重要的作用。基于 15 个血清型的荚膜基因座内变异的分子血清型鉴定比传统的血清学血清型鉴定更准确、更高效。为了减少运行时间并方便数据解释，我们开发了一种简单、快速的基于循环阈值（Ct）值的实时 PCR（qPCR）方法，用于鉴定和血清型鉴定副猪嗜血杆菌。qPCR 方法能够区分所有 15 个副猪嗜血杆菌参考菌株，效率值在 85.5%至 110.4%之间，R 值>0.98。使用 83 株临床分离株评估了 qPCR 血清型鉴定，其中 43 株分离株先前通过凝胶免疫扩散（GID）试验被分配到一个血清型，40 株非定型分离株。qPCR 结果与 GID 试验的结果一致，除了 2 株血清型 12 的分离株被分配到血清型 5 以外，43 株分离株中的 41 株（95.3%）。此外，qPCR 血清型鉴定为 40 株非定型分离株中的每一株都分配了一个血清型。在 83 株被测试以分配血清型的分离株中，qPCR 和 Howell 等人（2015 年）之前报道的多重 PCR 的一致性率为 98.8%（82/83）（包括那些血清型为 5 或 12 的分离株）。尽管不能区分血清型 5 和 12，但基于 Ct 值的 qPCR 血清型鉴定代表了一种有吸引力的替代目前用于副猪嗜血杆菌的分子血清型鉴定方法，可以用于流行病学监测和疫苗接种计划的指导。
