Aeromonas hydrophilia is the etiologic agent of motile aeromonas septicaemia, one of the most important bacterial diseases of fresh and marine water fishes. The aim of the present study was detection of A. hydrophilia in the aquarium goldfish an More
Aeromonas hydrophilia is the etiologic agent of motile aeromonas septicaemia, one of the most important bacterial diseases of fresh and marine water fishes. The aim of the present study was detection of A. hydrophilia in the aquarium goldfish and cultured rainbow trout in Chaharmahal va Bakhtiary province. In this study 50 goldfish from aquarium fish shops and 60 rainbow trouts suspected of having the disease from 6 farms (10 fish in each farm) were randomly collected. The average weight in goldfish and rainbow trout samples were 3-5 g and 10-20 g, respectively. Sampling was performed from kidney and liver, and inoculated into blood agar and incubated at 22°C for 24 hours. Pure colonies which are grown on the mediums were tested by catalase, oxidase and gram staining, then those of gram-negative, catalase and oxidase positive were diagnosed, and cultured on Shotts-Rimler medium (as selective medium for A. hydrophila). These mediums were incubated at 22 °C for 24-48 h. The typical colonies were tested by using oligonucleotide primers of lip gene by PCR method. In light of molecular analysis of all specimens, 9 and 6 isolates from rainbow trout and gold fishes were identified as A. hydrophila respectively. Due to the detection of A. hydrophila in both cultured rainbow trout and aquarium goldfish, the bacteria can lead to septicemia with mortality if the health management principles are not observed in fish farming.
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Aeromonas hydrophila is an important pathogenic agent in aquatics and zoonotic in humans. This pathogenic agent can extensively be found in water and also is a part of fishes' digestive system microflora. Extensive researches have been carried out on the antimicrobial e More
Aeromonas hydrophila is an important pathogenic agent in aquatics and zoonotic in humans. This pathogenic agent can extensively be found in water and also is a part of fishes' digestive system microflora. Extensive researches have been carried out on the antimicrobial effects of natural compounds against food-borne pathogens, indicating that these products can substitute antibiotics. Essential oils of Thymus carmanicus, Zataria multiflora, Cinnamomum verum, Rosmarinus officinalis have antimicrobial effects due to their phenolic compounds. In this study, the bioactive compounds were detected using Gas Chromatography equipped with the mass spectrometer. Then minimum inhibitory concentrations and minimum bactericidal concentrations of the essential oils against A. hydrophila were calculated. According to the results, the lowest and the highest MIC and the minimum MBC were observed in T. carmanicus and Z. multiflora, respectively. The result indicated that the inhibition zone diameter increased with the increase of essential oil concentration. The inhibition zone, in the concentration of 1500 ug mL-1 T. carmanicus was 24.33±0.57 mm. The findings of this study showed the antimicrobial resistance of these compounds. Considering the increasing limitations against chemicals and antibiotics, such compounds could be recommended for prevention.
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Infectious diseases are major economic losses in fish production facilities. Aeromonas hydrophila is considered as an important pathogen causing primary infection in wounds or the secondary problem following stress raised from temperature changes, handling, or poor More
Infectious diseases are major economic losses in fish production facilities. Aeromonas hydrophila is considered as an important pathogen causing primary infection in wounds or the secondary problem following stress raised from temperature changes, handling, or poor water quality. This study was aimed to isolate A. hydrophila from crayfish Astacus Leptodactylus and to determine its virulence genes. Ten infected crayfish were investigated in this descriptive study. Samples were cultivated on Brain Heart Infusion (BHI) Agar medium. Bacterial identification was performed using both biochemical and molecular tests. Also, the presence of three virulence genes (lipase, elastase, and aerolysin) was investigated in the isolates. Two A. hydrophila strains were isolated from 10 infected crayfish with symptoms including black plaque, abscess, soft shell, corrosion appendages, and lethargy. One of the isolated strains had lipase and elastase genes, and the other one contained lipase, elastase, and aerolysin virulence genes. Our results showed the presence of different virulence genes in different A. hydrophila strains isolated from infected crayfish. Further studies are required to clarify the role of these genes in pathogenicity and virulence-related symptoms in the aquatic species.
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Recognition of resistance and susceptibility of problematic bacteria such as Yersinia ruckeri and Aeromonas hydrophila in rainbow trout farms, in proper selection of antibiotics and infection control in breeding ponds. It plays an effective role. In this study, 100 dise More
Recognition of resistance and susceptibility of problematic bacteria such as Yersinia ruckeri and Aeromonas hydrophila in rainbow trout farms, in proper selection of antibiotics and infection control in breeding ponds. It plays an effective role. In this study, 100 diseased fish were collected from rainbow trout farms in Chaharmahal and Bakhtiari province and after performing biochemical tests and purification of Aeromonas hydrophila and Yersinia ruckeri species, using PCR test with specific primers were finally approved. Antibiotic susceptibility of bacteria was investigated by disk diffusion method by culture on Müller-Hinton agar medium. Examination of the results of antibiogram of Aeromonas hydrophila isolates showed that the highest resistance was related to the antibiotics ampicillin (100%), colistin (80%), enrofloxacin (80%), flumquin (80%) and then, Compared to tetracycline (60%) and fluorophenicol (60%) antibiotics. The most sensitive isolates were related to trimethoprim-sulfamethoxazole (60%) and phosphomycin (60%) antibiotics. Examination of the antibiogram results of Yersinia ruckeri isolates showed that the highest resistance among the isolates was related to the antibiotics ampicillin (100%), erythromycin (100), trimethoprim-sulfamethoxazole (100%) and colistin (83.34%) and then showed about 67% resistance to tetracycline, fluorophenicol and phosphomycin antibiotics. Resistance to the antibiotics flumequin, lincomycin + spectinomycin (lincospectin) and enrofloxacin were also observed to be 50%, which means that none of these antibiotics would be a viable option for the treatment of bacterial infections caused by Yersinia ruckeri. In order to avoid growing bacterial resistance and to take the most effective decision in terms of antibiotic therapy, usage of antibiotics without antibiogram must be avoided.
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