First isolation and characterization of the pathogenic Aeromonas veronii bv. veronii associated with ulcerative syndrome in the indigenous Pelophylax ridibundus of Al-Ahsaa, Saudi Arabia
First isolation and characterization of the pathogenic Aeromonas veronii bv. veronii associated with ulcerative syndrome in the indigenous Pelophylax ridibundus of Al-Ahsaa, Saudi Arabia
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DOI：
10.1016/j.micpath.2017.10.019
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发表时间：
2018-04-01
影响因子：
3.8
通讯作者：
Bekhet, Gamal
中科院分区：
文献类型：
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作者：
Khalifa, Ashraf Y. Z.;Bekhet, Gamal
有毒微生物病原体感染是全球两栖动物数量下降的主要原因。本研究对从红背褶蛙（Pelophylax ridibundus）幼虫皮肤中分离到的一株细菌RDL-2进行了培养，并利用扫描电镜观察、API 20 E试纸条和Biolog Gen III MicroPlate系统对其进行了表型和生化表征。获得了该菌株的16 S rRNA基因序列，并用于菌株鉴定和系统发育分析。用RDL-2攻击健康的P. ridibundus幼虫，并监测以确定与疾病一致的临床体征。根据菌株RDL-2的表型和生化特征，以及16 S rRNA基因序列和系统发育分析，将其鉴定为Veronii气单胞菌：RDL-2为革兰氏阴性菌，杆状，在94个性状中有69个（73%）呈阳性反应，其16 S rRNA基因序列与A.韦罗尼湾Veronii（99.9%）。科赫的假设得到了满足，证实了A. Veronii是溃疡综合征的病原体。因此，本研究首次报道了A. veronii作为沼泽蛙病原体在Al-Ahsaa地区。对A. veronii作为一种潜在的变温病原体，将加速诊断试验和根除溃疡综合征方法的发展。
Virulent microbial pathogen infections are the main cause for amphibian decline worldwide. In the present study, a bacterial strain named RDL-2, which was isolated from the skin of infected Pelophylax ridibundus larvae, was cultured and then phenotypically and biochemically characterized using scanning electron microscopic observations and the API20E strip and Biolog Gen III MicroPlate system. The 16S rRNA gene sequence of this strain was also obtained and used in strain identification and phylogenetic analysis. Healthy P. ridibundus larvae were challenged with RDL-2 and monitored to determine clinical signs consistent with the disease. Strain RDL-2 was identified as Aeromonas veronii based on its phenotypic and biochemical characteristics and on 16S rRNA gene sequence and phylogenetic analysis: RDL-2 was gram-negative, rod-shaped, and reacted positively for 69 (73%) of the 94 traits analysed; its 16S rRNA gene sequence displayed the highest homology to that of A. veronii by. veronii (99.9%). Koch's postulates were fulfilled confirming that A. veronii is the causal agent of ulcerative syndrome. Thus, this study is the first to report A. veronii as a marsh frog pathogen in the Al-Ahsaa region. The aetiology of A. veronii as a potential poikilothermic pathogen shown here will expedite the development of diagnostic tests and methods for eradicating ulcerative syndrome.