Zhu T F, Chen F F, Li J C
Collage of Animal Science and Technology, Anhui Agricultural University, Changjiang West Road 130, Hefei 230036, China.
Pol J Vet Sci. 2017 Dec;20(4):803-809. doi: 10.1515/pjvs-2017-0101.
Bacillus subtilis is a Gram-positive bacterium widely used in medicine and agriculture. So far, little is known about its pathogenicity in animals. In this study, a strain of Bacillus subtilis, HFBF-B11 isolated from brain tissue of ducklings co-infected with Riemerella anatipestifer was characterized. The strain demonstrated consistent characteristics of B. subtilis in staining and morphological, biochemical and physiological analyses. Moreover, its DNA sequence, which was obtained via PCR sequencing of 16S rRNA, exhibited 99% homology with the B. subtilis reference strain. In in vitro cultures HFBF-B11 exhibited β-hemolysis. The results of experiments showed that a single infection of HFBF-B11 in 9-day-old ducklings did not result in clear clinical symptoms. However, following co-infection with HFBF-B11 and R. anatipestifer, the animals demonstrated liver injury and blood-brain barrier disruption leading to infection and brain damage with a mortality rate of 100%. These results suggest that the HFBF-B11 strain of B. subtilis is an opportunistic pathogen of ducklings. This is the first report about the isolation of a B. subtilis strain with pathogenicity in ducklings.
枯草芽孢杆菌是一种革兰氏阳性菌，在医学和农业中广泛应用。到目前为止，人们对其在动物体内的致病性知之甚少。在本研究中，对从感染鸭疫里默氏杆菌的雏鸭脑组织中分离出的一株枯草芽孢杆菌HFBF - B11进行了特性鉴定。该菌株在染色、形态、生化和生理分析中表现出与枯草芽孢杆菌一致的特征。此外，通过16S rRNA的PCR测序获得的其DNA序列与枯草芽孢杆菌参考菌株具有99%的同源性。在体外培养中，HFBF - B11表现出β - 溶血现象。实验结果表明，9日龄雏鸭单独感染HFBF - B11并未导致明显的临床症状。然而，在与HFBF - B11和鸭疫里默氏杆菌共同感染后，雏鸭出现肝损伤和血脑屏障破坏，导致感染和脑损伤，死亡率达100%。这些结果表明，枯草芽孢杆菌HFBF - B11菌株是雏鸭的一种机会致病菌。这是关于分离出具有雏鸭致病性的枯草芽孢杆菌菌株的首次报道。
