Molecular Characterization, Antimicrobial Susceptibility and Salt Tolerance of Aeromonas hydrophila from Fresh, Brackish and Marine fishes

Dahdouh, Basma; Basha, Ola; Khalil, Sarah; Tanekhy, Mahmoud

doi:10.5455/ajvs.208107

Cited by 21 publications

(17 citation statements)

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“…In addition, congestion of the liver and spleen was also defined. Our results were in concordance with the findings reported by Afifi et al (2000), Sarkar and Rashid (2012) and Dahdouh et al (2016).…”

Section: Discussionsupporting

confidence: 94%

Natural co‐infection of cultured Nile tilapiaOreochromis niloticuswithAeromonas hydrophilaandGyrodactylus cichlidarumexperiencing high mortality during summer

Abdel‐Latif

Khafaga

2020

Aquac Res

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Aeromonas hydrophila and Gyrodactylus cichlidarum are common pathogens that induce significant economic losses in farm‐reared Nile tilapia. Nowadays, the sudden appearance of fish mortalities was exaggerated due to mixed and multiple infections. During summer 2016, mass mortality among earthen pond‐farmed Nile tilapia was reported. Clinico‐pathological, bacteriological and parasitological examinations have been demonstrated. As well, the water quality parameters were assessed. The clinical and histopathological findings of the moribund and recently dead fish were characterized by generalized septicaemic signs. The water quality parameters were significantly elevated over the permissible levels, whereas there was an elevation in nitrite (0.04 mg/L), un‐ionized ammonia (0.8 mg/L), hydrogen sulphide levels (153.1 mg/L) and organic matter content (3.79 mg/L). A. hydrophila was identified based on phenotypic characterization, API 20E features and the homology of 16S rRNA gene sequence analysis. In addition, PCR data confirmed the presence of aerolysin (aerA) and haemolysin (hly) genes in the identified A. hydrophila isolates. Gene sequencing and phylogenetic analysis based on 16S rRNA sequence confirmed that A. hydrophila H/A (accession No. MN726928) of the present study displayed 98%–99% identity with the 16S rRNA gene of A. hydrophila. Furthermore, the monogenetic trematode, G. cichlidarum was identified in the wet mounts from the skin and gills of the examined fish with a high infestation rate. In this context, it was reported that the synergistic co‐infection of A. hydrophila and G. cichlidarum with deteriorated water quality parameters could induce exaggerated fish mortalities during hot weather.

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Section: Discussionsupporting

confidence: 94%

Natural co‐infection of cultured Nile tilapiaOreochromis niloticuswithAeromonas hydrophilaandGyrodactylus cichlidarumexperiencing high mortality during summer

Abdel‐Latif

Khafaga

2020

Aquac Res

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“…The most prevalent bacterial isolates were aeromonads (14 isolates, 48.3 %). These findings nearly like that recorded by Hanafy (2005), Dahdouh et al (2016) and Abd El-Kader and Mousa-Balabel (2017). Almost all the obtained bacteria were isolated from kidneys and liver samples.…”

Section: Discussionsupporting

confidence: 89%

Insight into summer mortality syndrome in farmed Nile tilapia (Oreochromis niloticus) associated with bacterial infection.

Asely

Youssuf

Gawad

et al. 2020

Benha Veterinary Medical Journal

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The current investigation was undertaken to determine the potential causes of summer mass mortalities among farmed Nile tilapia (Oreochromis niloticus). Pure bacterial colonies were isolated from moribund O. niloticus from 13 different fish farms suffered from high mortalities ranged from (50-80%), during the period from April to October 2018. Fish showed external hemorrhagic spots, skin darkening, abdominal distension and exophthalmia. Internally, congestion and enlargement of internal organs with serous or hemorrhagic fluid was the most obvious picture. The phenotypic and biochemical characterization using API20E identified the bacterial isolates as (A. veronii, A. hydrophila, A. caviae and A. sobria; Aeromonads), (Ps. Fluorescence; Pseudomonas spp), (E. sakazakii and E. cloacae; Enterobacter spp), (C. freundii; Citrobacter spp), (S. odorifera, S. liquefaciens, and S. marcescens; Serratia spp), (S. lutiensis, S. equine; Streptococcus spp), Lactococcus lactis and Proteus vulgaris, with the most prevalence to aeromonads. Most isolates were accurately identified by PCR and gene sequencing. Water physicochemical parameters were measured at the farm sites showed an increase in the pH and ammonia levels. In order to confirm the pathogenicity of the bacterial isolates, an experimental infection was conducted using different doses. The results revealed that A. veronii (HY2) at dose of 9×10 8 cells/ml was the most pathogenic with mortality rate 100 %. This study concludes that A. veronii, C. freundii, P. vulgaris and P. fluorescens are implicated in Nile tilapia summer mortalities, without neglecting the role of water quality in worsening the problem. Bacterial infection.

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“…The observed clinical signs of infected Nile tilapia in the current study are similar to those reported by Dahdouh, Basha, Khalil, and Tanekhy (2016); Harikrishnan and Balasundaram (2005); Sarkar and Rashid (2012). These gross lesions, including hemorrhagic patches, can be attributed both to bacterial invasion, multiplication, and colonization as well as to toxins produced by invading microorganism(s) (Miyazaki & Kaige, 1986).…”

Section: Discussionsupporting

confidence: 88%

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Elsheshtawy¹,

Yehia²,

El‐Kemary³

et al. 2019

GenAqua

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Aquaculture sector in Egypt has demonstrated a remarkable development; however, it has also faced challenges with respect to disease outbreaks. Nile tilapia is the most widely cultured species in Egypt. Under stress conditions, tilapia is vulnerable to a variety of bacterial diseases that tend to be ubiquitous in the freshwater environment. Semi-intensive Nile tilapia farms in Kafr El-Sheikh Governorate, Egypt are experiencing acute mortality especially during summer months. The samples from these farms were collected and subjected to investigations to identify the etiological agent(s) behind these mortalities. Bacteriological examination revealed that the dominant bacteria were Gram-negative rods and identified as Aeromonas spp. through biochemical tests. PCR, restriction fragment length polymorphism (RFLP) assays, and sequencing confirmed the presence of Aeromonas hydrophila. In addition, the aerA gene, a virulence factor in A. hydrophila, was detected by PCR in all identified A. hydrophila isolates. In order to confirm that the isolated A. hydrophila was the causative agent of tilapia mortality, healthy Nile tilapia were challenged with the isolated strains, which produced the same clinical picture of the collected samples. This study implicates that A. hydrophila could be the causative agent of the summer mortality in Nile tilapia farms in Kafr El-Sheikh Governorate, Egypt.

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Molecular Characterization, Antimicrobial Susceptibility and Salt Tolerance of Aeromonas hydrophila from Fresh, Brackish and Marine fishes

Cited by 21 publications

References 0 publications

Natural co‐infection of cultured Nile tilapiaOreochromis niloticuswithAeromonas hydrophilaandGyrodactylus cichlidarumexperiencing high mortality during summer

Natural co‐infection of cultured Nile tilapiaOreochromis niloticuswithAeromonas hydrophilaandGyrodactylus cichlidarumexperiencing high mortality during summer

Insight into summer mortality syndrome in farmed Nile tilapia (Oreochromis niloticus) associated with bacterial infection.

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