Molecular Studies on Aeromonas Species Isolated from Freshwater Fishes Collected from Delta Region, Egypt

Abstract

The current study was carried out to identify suspected causes of septicemia in naturally infected freshwater fishes collected from different fish farms at different localities in Menofiya and Kafr El-Sheikh Provinces, Egypt. Fishes (n=120) were examined clinically and upon post-mortem. Bacteriological isolation and identification of the bacterial pathogens using traditional and molecular methods were demonstrated. Based on the phenotypic and biochemical characterization using API20E, API 20 NE and VITEK® 2 compact, the isolated bacteria were identified as Aeromonads (A. hydrophila and A. veronii). Molecular characterization was accomplished through polymerase chain reaction (PCR) and confirmed by sequencing and phylogenetic analysis. The high molecular identity and close phylogenetic relationship confirmed that the isolates were genetically homologous to A. hydrophila and A. veronii. Thus, this study proves that motile aeromonads remain important bacterial pathogens from aquaculture point of view in Egypt, which requires regular and permanent examination of cultured fishes to resist mass mortalities which lead to economic losses.

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

“…The isolates were characterized based on their growth on GSP selective agar medium: yellow colonies, rod shape, Gram-negative, motile, and production of acid from glucose (Table-2). These characteristics have also been reported previously by El-Sharaby et al [5]. In addition, Aeromonas can ferment glucose.…”

“…These characteristics have also been reported previously by El-Sharaby et al . [ 5 ]. In addition, Aeromonas can ferment glucose.…”

“…is one of the most serious and devastating causes of losses in catfish culture [1][2][3]. These Gram-negative, oxidase-positive, and facultative anaerobic, bacteria normally live in an aquatic environment [4][5][6]. Aeromonas spp.…”

Antibacterial activity of ethanol extract of banana, cassava, and pineapple peels against a fish pathogen Aeromonas hydrophila

“…Aeromonas hydrophila is one of the pathogenic bacteria that often infect many freshwater fish. Aeromonas hydrophila is a Gram-negative, bacillus-shaped with rounded ends, nonspore, motile, facultative anaerobic (Stratev and Odeyemi 2016;Abeyta et al 2019;Yazdanpanah-Goharrizi et al 2020;El-Sharaby et al 2021;Mailafia et al 2021). The mechanism of bacterial pathogenicity is quite complex and related to virulence factors (Li et al 2015).…”

Antibacterial activity of mangrove plant extract of Rhizophora apiculata in inhibiting the growth of various strains of Aeromonas hydrophila

“…This disease is caused by species from the genus Aeromonas, one of which is Aeromonas hydrophila (Lopamudra et al 2020;Monir et al 2020;Zhang et al 2020;Mulia et al 2022a). A. hydrophila is a rod-shaped, Gram-negative, motile, chemoorganoheterotrophic, facultative anaerobic, oxidasepositive, catalase positive, fermentative, non-spore, and opportunistic (Mulia et al 2011;Stratev and Odeyemi 2016;Abeyta et al 2019;Pessoa et al 2019;El-Sharaby et al 2021;Semwal et al 2023).…”