Aeromonas Infections in African Sharptooth Catfish

Abstract

The aim of this study was to investigate the dominant species of Aeromonas in naturally infected African Sharptooth catfish, Clarias gariepinus, in Qena, Egypt and the distribution of two virulence genes among the isolates to assess their pathogenicity. Twenty-five isolates of Aeromonas were recovered from infected fish showing signs of septicemia. Restriction-fragment-length-polymorphism (RFLP) analysis of the 16S-rDNA amplified products demonstrated that the specie isolated were Aeromonas hydrophila (56%) and Aeromonas veronii (44%). Isolates were screened for the cytotoxic enterotoxin, act, and aerolysin, aerA, genes. The act gene was detected only in A. hydrophila, while the aerA gene was more frequently found among all isolates. Catfish challenged with an A. hydrophila isolate that have both the act and aerA genes showed higher mortalities (80.9%) and more severe signs of septicemia than those challenged with an isolate that lacks both genes studied.

Isolation, genetic characterization, and virulence profiling of different Aeromonas species recovered from moribund hybrid catfish (Clarias spp.)

“…This study also showed that Aeromonas have at least four virulence genes. Similar results have been reported for aer/haem and flaA [ 30 , 62 ]. Aerolysin is a hemolytic extracellular product coded by the aerolysin gene and plays a significant role in the pathogenicity of Aeromonas spp.…”

“…The previous study has also identified Aeromonas spp. from catfish ( Clarias gariepinus ) in Egypt using genotypic analysis, these bacteria consisted of A. hydrophila (56%) and A. veronii (44%) [ 62 ], A. hydrophila (50.4%), and A. caviae (5.6%) according to phenotypic analysis [ 63 ]. Other research on catfish in Uganda discovered A. hydrophila (33%) and A. sobria (33%) through genotypic analysis [ 13 ].…”

Comparative Pathogenicity of Aeromonas spp. in Cultured Red Hybrid Tilapia (Oreochromis niloticus × O. mossambicus)

“…This disease is caused by members of the genus Aeromonas, such as Aeromonas hydrophila, A. veronii, A. dhakensis, A. jandaei, A. sobria and A. caviae [7][8][9][10][11][12]. The disease was described as having two forms, the acute hemorrhagic septicemia and the chronic ulcerative syndrome [13][14][15]. The genus Aeromonas plays an important role in diseases of aquaculture, with Aeromonas spp.…”

Pengobatan Lele Dumbo (Clarias gariepinus L.) yang Terinfeksi Aeromonas hydrophila di Kabupaten Banyumas dengan Menggunakan Ekstrak Daun Api-Api (Avicennia marina)

“…Bakteri ini menyebabkan penyakit MAS dalam spektrum yang luas pada ikan maupun biota air lainnya (Zhou et al, 2011;Qi et al, 2016;Raji et al, 2019). Gejala yang ditimbulkan pada lele yang terinfeksi A. hydrophila antara lain hemoragik yang tersebar di seluruh bagian tubuh, pengelupasan dan congesti pada sirip ekor, ulcer, hemoragik dan kongesti pada hati, ginjal,dan limpa, serta abdominal cavity (Emeish et al, 2018).…”