Department of Microbiology and Hygiene, Bangladesh Agricultural University, Mymensingh-2202, Bangladesh; Gono Bishwabidyalay, Dhaka, Bangladesh.
Department of Microbiology and Hygiene, Bangladesh Agricultural University, Mymensingh-2202, Bangladesh.
Comp Immunol Microbiol Infect Dis. 2024 Dec;115:102272. doi: 10.1016/j.cimid.2024.102272. Epub 2024 Oct 29.
This study aimed to investigate the concurrent infection of Pasteurella multocida (P. multocida) type B:2, which causes Hemorrhagic Septicemia (HS), with cases of Foot and Mouth Disease (FMD) outbreaks in cattle in Bangladesh between March and December 2023. Samples were collected from 11 distinct outbreak areas, totaling 102 samples. These included 54 FMD samples (saliva, tissue epithelium, and morbid tissues such as lung, spleen, and heart) and 54 HS samples (nasal swabs and morbid tissues) from 50 cattle of various ages and sexes, all showing clinical signs of suspected concurrent HS and FMD infection. After sample processing, molecular detection of FMDV and its serotypes was performed using Reverse Transcriptase PCR (RT-PCR) with universal and serotype-specific primers. The HS-causing agent, P. multocida type B:2, was initially identified through cultural and morphological characteristics on various media, followed by Gram's and methylene blue staining, biochemical tests, and pathogenicity tests through inoculation of isolates into mice. Finally, molecular detection of P. multocida type B:2 was confirmed using PCR with specific primers. Forty-five (83 %) of the 54 FMD suspected samples tested positive for FMDV, with 53 % of these positive for serotype 'O,' 17 % for serotype 'A,' and 6 % for mixed serotypes 'O' and 'A.' Among the FMDV-positive samples, 17 (38 %) of the HS-suspected samples tested positive for concurrent infection with P. multocida type B:2. The study reveals that FMDV-induced acute immunosuppression in cattle can lead to complications from concurrent infections, particularly those caused by P. multocida type B:2, resulting in HS alongside FMD.
本研究旨在调查 2023 年 3 月至 12 月期间孟加拉国牛群中发生的 B 型 2 型多杀巴斯德菌（引起出血性败血症（HS））与口蹄疫（FMD）暴发的并发感染。从 11 个不同的暴发地区采集了 102 个样本，包括来自 50 头不同年龄和性别的牛的 54 个 FMD 样本（唾液、组织上皮和肺部、脾脏和心脏等病态组织）和 54 个 HS 样本（鼻腔拭子和病态组织），所有这些样本都表现出疑似同时感染 HS 和 FMD 的临床症状。在样品处理后，使用通用和血清型特异性引物的逆转录聚合酶链反应（RT-PCR）对 FMDV 及其血清型进行分子检测。首先通过在各种培养基上的培养和形态特征初步鉴定引起 HS 的 B 型 2 型多杀巴斯德菌，然后通过革兰氏和亚甲蓝染色、生化试验以及通过将分离株接种到小鼠中进行致病性试验。最后，使用特异性引物的 PCR 确认 B 型 2 型多杀巴斯德菌的分子检测。在 54 个疑似 FMD 的样本中，有 45 个（83%）对 FMDV 呈阳性，其中 53%为血清型'O'，17%为血清型'A'，6%为混合血清型'O'和'A'。在 FMDV 阳性样本中，有 17 个（38%）疑似 HS 的样本对 B 型 2 型多杀巴斯德菌的并发感染呈阳性。研究表明，FMDV 诱导牛的急性免疫抑制会导致并发感染的并发症，特别是由 B 型 2 型多杀巴斯德菌引起的感染，导致 HS 与 FMD 同时发生。
