Control Of Furunculosis Research Articles

Characterization and mechanism of anti-Aeromonas salmonicida activity of a marine probiotic strain, Bacillus velezensis V4.

The bacterium Aeromonas salmonicida is the causative agent of furunculosis, a systemic, ubiquitous disease of fish in the salmon family, characterized by high mortality and morbidity. Probiotics are a promising approach for prevention of furunculosis in aquaculture. A bacterial strain with anti-A. salmonicida properties, Bacillus velezensis V4, was isolated and the mechanisms underlying these properties were investigated. Anti-A. salmonicida compounds present in cell-free supernatant of V4 were purified and structurally identified as members of the iturin, macrolactin, and difficidin groups. The compounds contributed jointly to inhibition of A. salmonicida, and the diversity of the compounds was related to the versatility of their mode of action. Addition of the compounds to A. salmonicida cell suspensions reduced cell density. Analyses by confocal microscopy and scanning electron microscopy revealed cell membrane disruption, deletion of cellular content, and cell lysis of A. salmonicida. The V4 genome was sequenced, and gene clusters involved in synthesis of anti-Aeromonas compounds were detected and identified. A possible probiotic effect on growth performance of Oncorhynchus mykiss (rainbow trout) was investigated by addition of 0, 1, and 3% (v/w) V4. Relative to control, mortality was reduced 27.25% in the 1% addition group and 81.86% in the 3% addition group. Feed coefficient ratio was reduced 19.49% and weight gain ratio was increased 71.22% in the 1% addition group. Our findings demonstrate that V4 is an effective probiotic strain in O. mykiss and has clear potential for both control of furunculosis and growth promotion of aquaculture animals.

Control of Furunculosis and Enteric Redmouth Disease in Sea-Run Atlantic Salmon Broodstock in the Connecticut and Merrimack Rivers

Abstract Adult sea-run Atlantic salmon Salmo salar captured and transported to Richard Cronin National Salmon Station (Sunderland, Massachusetts), Nashua National Fish Hatchery (Nashua, New Hampshire), and Whittemore State Fish Hatchery (Waterford, Connecticut) during 1986–1992 were treated with oxolinic acid and a bacterin. The bacterin was developed against furunculosis and enteric redmouth disease. Among the 2,552 fish that were treated since 1986, 362 died and 65 (18%) of those fish had furunculosis. Among 206 untreated fish that were maintained as controls, 109 died and 63 (57.8%) had furunculosis. The reduction in mortality could not be attributed to either vaccine or antibiotic alone without further study. A 3-year study was designed to investigate if adult Atlantic salmon, undergoing the stress of migration, handling, and spawning, could mount a protective humoral immune response. Although the salmon were able to produce an agglutinin response, evidence was not found for production of a protective...

Amoxycillin in the control of furunculosis in Atlantic salmon parr.

The efficacy of amoxycillin in the control of laboratory induced Aeromonas salmonicida infection in Atlantic salmon parr was investigated. When given in the diet at a dose rate of 80 mg per kg bodyweight it was effective against both a moderate and severe challenge (with mortality rates in untreated groups of 75 per cent and 45 per cent). At 40 mg per kg it was effective against the moderate challenge only. The plasma levels in these regimens were 1.25 micrograms per ml and 0.3 to 0.6 micrograms per ml and the minimum inhibitory concentration of the challenge strain of A salmonicida was 0.6 micrograms per ml. The potential of the Charm radiobioassay system in detecting antibiotic residues in fish tissue was studied. The level of amoxycillin in muscle and bone from fish in mid-treatment at 80 mg per kg was 0.32 micrograms per ml. After a 12 day withdrawal period at 18 degrees C no residue was detected within the 0.005 micrograms per ml limit of this test.

Florfenicol in Atlantic salmon, Salmo salar L., parr: tolerance and assessment of efficacy against furunculosis

Abstract. The efficacy of florfenicol against laboratory‐induced infection with Aeromonas salmonicida was tested in Atlantic salmon, Salmo salar L., parr. Medication at three dose levels in the feed was started 24 h after bath challenge with A. salmonicida. The specific mortality rate in the unprotected infected control group was 75% compared with 5, 13 and 17% when florfenicol was given at dose levels of 20, 10 and 5 mg per kg body weight per day, respectively. Florfenicol was palatable to the fish at doses in excess of effective therapeutic levels and feeding for 10 days at 100 mg per kg, or for prolonged periods at 50 mg per kg and 10 mg per kg, resulted in no feeding problems or histopathological abnormalities. Florfenicol appears to have a good therapeutic index and considerable potential in the control of furunculosis in salmon.

Antibiotic resistance of Aeromonas salmonicida isolated from Atlantic salmon, Salmo salar L., in Scotland

Abstract. Antibiotic sensitivity patterns of 304 isolates of Aeromonas salmonicida from 229 outbreaks of furunculosis among salmon in Scotland between 1988 and 1990 were investigated. Fifty‐five per cent were resistant to oxytetracycline and 37% resistant to oxolinic acid. Multiple resistance was common (52%) and 18 out of 19 antibiograms which were found in the first year recurred in the succeeding year. More than a quarter of the outbreaks were associated with two or more A. salmonicida variants distinguishable by their antibiotic sensitivity patterns. The implications of these findings in the control of furunculosis are considered.

Emploi de la fluméquine contre la furonculose des salmonidés : essais thérapeutiques et perspectives pratiques

The bactericidal activity of the flumequine, a synthetic derivative of the « quinolones » family, has been recently recognized and has resulted in its common use in human and veterinary medicine. The availability of an artificial model of trout furunculosis allowed to test its curative properties in Aeromonas saimonicida infection. For this purpose, we have used 2 species of trout (Salmo gairdneri and S. trutta), and 2 pathogenic strains of which LD 50 ranged initially from 400 to 800 bacteria/fish, intramuscularly (IM). Fish, divided in 3 groups, received respectively 20 g, 40 g an 80 g of Flumix (flumequine powder with 3 % of active component) per 100 kg of b.w./day during 6 days, representing 1, 2 and 4 times the mammalian dose. The drug was stuck on dry pellets supplied twice a day as 1 % of b.w. Fingerlings were arranged in 30 subjects groups maintained in 15°C flow-through tanks, and experimentally infected by IM injection of about 1 or 10 LD 50. A preliminary administration of 200g/100kg of fish of Flumix was done on a sample during a fortnight and did not result in any observation of acute toxicity. A conspicuous protective effect of the drug was noticed in all cases the treatment was carried on at the same day as the infection. Differences between mortality percentages in controls and treated fish were about 60 p. 100, whatever the trout species ant the bacterial strain. Variations were of trifling importance according to the therapeutic doses, and when testing fish with high doses of pathogen ([MATH] 10 LD 50) the effect seemed better, resulting of the higher mortality of controls. In some cases, the treatment was started 20 hours after inoculation of Aeromonas. Except in one case, the protection was then very lowered, and this has been ascribed to the loss of appetite of diseased subjects In conclusion, the efficacy of flumequine treatments in control of furunculosis is stated and some practical indications are given. The dose of 40g/100 kg of fish of flumequine powder (40 g/kg of food when feeding at 1 %) is recommended for fish, diet being distributed in 2 meals, and the rules of every other antimicrobial treatments being respected.

In Vitro and In Vivo Efficacy of a Potentiated Sulfonamide in Control of Furunculosis in Salmonids

In vitro and in vivo efficacy of a potentiated sulffonamide, Ro5–0037, for inhibition of Aeromonas salmonicida, causative agent of fish furunculosis was determined. The components of the potentiated sulfonamide, sulfadimethoxine, and ormetoprim were tested alone and in combination. In vitro results showed that both sulfonamide-resistant and sensitive strains of A. salmonicida had greater sensitivity to Ro5–0037 than to either of its components. Also, sulfonamide-sensitive strains developed resistance to ormetoprim and sulfadimethoxine more rapidly than to Ro5–0037. Efficacy studies with small numbers of artificially infected trout revealed that Ro5–0037 effectively controlled furunculosis at 50 mg/kg of fish/day, one fourth the usual sulfonamide dosage level. Extensive field trials also showed the 50 mg/kg level of Ro5–0037 gave effective control of hatchery outbreaks of furunculosis. As found in the in vitro studies, all in vivo trials indicated the combination of ormetoprim and sulfadimethoxine was more efficient in inhibiting A. salmonicida than either component alone.

Control of furunculosis in impounded adult salmon.

FROM July 27 to August 17, 1964, 17 salmon were found dead among about 40 fish impounded at Ceannacroc on the Moriston, a tributary of the River Ness. Eight salmon examined between August 1 and 14 showed typical symptoms of furunculosis, and pure cultures of the causative organism, Bacterium salmonicida, were isolated from the internal organs and muscle. As a serious outbreak of furunculosis had occurred in this impoundment and at another impoundment on the Ness system in 1963, an attempt was made to control the outbreak which seemed to threaten this year.

Furazolidone (nf-180) for Control of Furunculosis in Trout

Furazolidone (nf-180) for Control of Furunculosis in Trout

Further Laboratory Studies on the Use of Furazolidone for the Control of Furunculosis of Trout

Further Laboratory Studies on the Use of Furazolidone for the Control of Furunculosis of Trout

A Possible Control of Furunculosis

(1961). A Possible Control of Furunculosis. The Progressive Fish-Culturist: Vol. 23, No. 3, pp. 136-137.