جستجوی مقالات مرتبط با کلیدواژه « yersinia ruckeri » در نشریات گروه « زیست شناسی »

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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This study aimed at investigating the antibacterial effects of extracts from leaf, fruit, and stem of Solanum nigrum on fish pathogenic bacteria. The extraction process was done using the rotary device. The leaf methanol extract and the fruit acetone extract (MIC and MBC of 25 and 12.5 ppm, respectively) showed stronger antibacterial properties. The Streptococcus iniae were the most resistant bacteria against case studies. The Aeromonas hydrophila has been found to be the most resistant bacteria in the fruit methanol and hexane extract. The stem and leaf acetone extracts showed the maximum diameter of the zones of bacterial growth inhibition on Yersinia ruckeri and Aeromonas hydrophila (concentration = 50 ppm) bacteria respectively. Furthermore, the minimum diameter of the zones of bacterial growth inhibition belonged to the leaf hexane extract on Yersinia ruckeri bacteria (concentration = 25 ppm). That using the leaf methanol extract and fruit acetone extract of Solanum nigrum is effective in treating bacterial diseases of the aquaculture.

This study was conducted to evaluate the effects of different levels of Mentha piperita extract on growth factors, body composition, intestinal bacteria and survival rate of Oncorhynchus mykiss in challenging with Yersinia ruckeri. For this purpose, four groups of fish with mean weight of 32. 2± 0.12 g were raised for 8 weeks in Vniro tanks, 80 fish to each tank and feeding with different levels of M. piperita (with concentrations of % 0, % 1, % 2.0 and % 3.0, 3 replicates for each treatment). At the end of the trial, growth factors, intestinal bacteria and survival rate of fish in challenging with Y. ruckeri were determined in different groups. Results showed that O. mykiss fed on a diet supplemented with 3% M. piperita had significantly higher growth factors, lactic acid bacteria, and survival rate compared to other treatments (P0.05). Based on the results, using of M. piperita extract, especially at the level of 3 % can improve the growth performance and survival rate of O. mykissmykiss in challenging with Y. ruckeri and was recommended in the diet.

Yersinia ruckeri is the etiological agent of enteric redmouth (ERM) disease, one of the important bacterial diseases in the cultured salmonids. The aim of present study was detection of virulence genes (yrpE and yrp1) in the Y.ruckeri bacterium In this study fish were evaluated in average size 10-12 Cm from six rainbow trout farms in Chaharmahal-Va-Bakhtiary province. In each farm 10 fish (totally 60) suspected to ERM were randomly selected, sampling was done from lower part of intestine and cultured on general (trypticase soy agar) and specific (Waltman-Shots) mediums. Finally, colonies that were isolated on these mediums tested by PCR method for Y.ruckeri detection. Then, in the identified strains of Y.ruckeri virulenc genes (yrp1 and yrpE) were detected by PCR test. In the all strains of Y. ruckeri two virulence genes (yrp1 and yrpE) were identified by molecular test. 24 strains out of total isolates were identified as Y.ruckeri, and among them 12 cases (50%) and 11 cases (45. 83%) had yrp1 and yrpE genes, respectively. Also, 6 samples (25%) had both genes simultaneously. Discussion and The study revealed that virulence factor yrp1 is as extracellular protease presence in Y.ruckeri strains. T his factor plays an important role in the bacterial virulence and pathogenesis of ERM disease. Data obtained in this study help to control disease especially in development of current vaccines.