Praveen Kumar N, Vinod Kumar N, Karthik A
Department of Veterinary Microbiology, College of Veterinary Science, SV Veterinary University, Tirupathi, Andhra Pradesh, India.
Trop Anim Health Prod. 2019 Jul;51(6):1559-1569. doi: 10.1007/s11250-019-01847-9. Epub 2019 May 10.
A total of 464 samples comprising of cloacal swabs from necrotic enteritis suspected live birds (191), intestinal scrapings from dead birds with symptoms of necrotic enteritis (91), and apparently healthy birds (182) were collected from selected districts of AP. The samples were subjected to multiplex PCR for simultaneous detection of α, β, and β2 toxin genes and uniplex PCR for the detection of NetB gene. Multiplex PCR screening of samples reveled α toxin gene positives from (cpa) 248/282 (87.94%) necrotic enteritis suspected and 40/182 (21.97%) apparently healthy samples. Among cpa positives 142/248 (57.25%) and 3/40 (7.5%) were positive for β2 toxin gene in necrotic enteritis suspected and apparently healthy birds respectively, indicating the involvement of C. perfringens type A, with minor pore forming toxin gene cpb2 in causing necrotic enteritis in poultry. None of the sample was positive for β toxin gene. The present research indicates C. perfringens type A along with β2 toxin gene was responsible for causing necrotic enteritis in broiler chickens in some parts of Andhra Pradesh in India. Phylogenetic relationship of amplified cpa and cpb2 amino acids sequences from present C. perfringens isolates were studied. The analysis reveals the sequence identity of cpb2 gene of the present isolates and variations at both nucleotide and amino acid level with the published sequences of cpb2 gene of C. perfringens isolates from different animal species of the USA, Iran, Netherlands, and Japan.
从印度安得拉邦选定地区共采集了464份样本，包括疑似坏死性肠炎活禽的泄殖腔拭子（191份）、有坏死性肠炎症状的死禽的肠道刮取物（91份）以及外观健康的禽类（182份）。对这些样本进行多重PCR以同时检测α、β和β2毒素基因，并进行单重PCR以检测NetB基因。对样本进行多重PCR筛选发现，在疑似坏死性肠炎的样本中，有248/282（87.94%）的样本α毒素基因呈阳性，在外观健康的样本中有40/182（21.97%）呈阳性。在α毒素基因呈阳性的样本中，疑似坏死性肠炎的禽类中有142/248（57.25%）、外观健康的禽类中有3/40（7.5%）的β2毒素基因呈阳性，这表明A型产气荚膜梭菌以及次要的成孔毒素基因cpb2参与了家禽坏死性肠炎的发生。没有样本β毒素基因呈阳性。本研究表明，A型产气荚膜梭菌连同β2毒素基因是印度安得拉邦部分地区肉鸡坏死性肠炎的病因。对当前产气荚膜梭菌分离株扩增的cpa和cpb2氨基酸序列的系统发育关系进行了研究。分析揭示了当前分离株cpb2基因的序列同一性以及与来自美国、伊朗、荷兰和日本不同动物物种的产气荚膜梭菌分离株cpb2基因已发表序列在核苷酸和氨基酸水平上的差异。
