Penicillin-G: Efficacy against Flavobacterium psychrophilum and evaluation of lethal dose limits for rainbow trout


The effect of penicillin-G on Flavobacterium psychrophilum, the cause of bacterial coldwater disease, was evaluated in 15 min and overnight exposures. Separate tests evaluated the effect of increasing doses of penicillin-G to rainbow trout Oncorhynchus mykiss eggs, fingerlings, and adults. Rainbow trout eggs were exposed for 1 h to penicillin doses of 0, 250, 500, 1,000, 10,000, 50,000, or 100,000 IU/mL. Mean percent hatch ranged from 64.6% to 75.1%, and did not significantly differ among the treatments. Fingerlings were injected intraperitoneally (i.p.) with 200 μL of 0, 1, 10, 100, 1,000, 10,000, 100,000, or 500,000 IU/mL. Probit analysis resulted in a LD10 (lethal dose for 10% of injected fish) of 52,868 IU/mL (95% confidence limits: 31,522 - 69,490 IU/mL) and a LD50 of 131,466 IU/mL (113,095 - 157,878 IU/mL). Brood stock were injected (i.p.) with 200 μL of penicillin at concentrations of 0 (control), 10,000, 50,000, 100,000, 200,000, 400,000, or 800,000 IU/mL. Mortality ranged from 0% to 7% (50,000 IU/mL treatment) and did not significantly differ among treatments. In 28 h exposure tests, penicillin concentrations of ≥ 333 IU/mL were required to completely suppress growth of F. psychrophilum. In 15 min exposures, ≥ 10,000 IU/mL were needed to achieve the same result. Tests indicated that rainbow trout eggs can tolerate 1 h exposures to penicillin-G concentrations as high as 100,000 IU/mL, and that brood fish can tolerate injections of at least 800,000 IU/mL. Fingerling data however, suggested that injection of doses greater than 10,000 IU/mL can be toxic. The data suggests rainbow trout eggs or brood can tolerate high doses of penicillin-G that could be used for controlling the transfer of F. psychrophilum to hatcheries receiving eggs.

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Wagner, E. , Oplinger, R. and Bartley, M. (2012) Penicillin-G: Efficacy against Flavobacterium psychrophilum and evaluation of lethal dose limits for rainbow trout. Open Journal of Animal Sciences, 2, 150-158. doi: 10.4236/ojas.2012.23021.

Conflicts of Interest

The authors declare no conflicts of interest.


[1] Cipriano, R.C. and Holt, R.A. (2005) Flavobacterium psychrophilum, cause of bacterial cold-water disease and rain-bow trout fry syndrome. Fish Disease Leaflet 86, US Geological Survey, National Fish Health Laboratory, Kearneysville, West Virginia.
[2] Wagner, E.J., Oplinger, R.W., Arndt, R.E., Forest, A.M. and Bartley, M. (2010) The safety and effectiveness of various hydrogen peroxide and iodine treatment regimens for rainbow trout egg disinfection. North American Journal of Aquaculture, 72, 34-42. doi:10.1577/A09-005.1
[3] Kumagai, A., Takahashi, K., Yamaoka, S. and Wakabayashi, H. (1998) Ineffectiveness of iodophore treatment in disinfecting salmonids eggs carrying Cytophaga psychrophila. Fish Pathology, 33, 123-128. doi:10.3147/jsfp.33.123
[4] Cipriano, R.C. (2005) Intraovum infection caused by Flavobacterium psychrophilum among eggs from captive Atlantic salmon broodfish. Journal of Aquatic Animal Health, 17, 275-283. doi:10.1577/H05-003.1
[5] Wagner, E.J., Arndt, R.E., Billman, E.J., Forest, A. and Cavender, W. (2008) Comparison of the efficacy of iodine, formalin, salt, and hydrogen peroxide for control of external bacteria on rainbow trout eggs. North American Journal of Aquaculture, 70, 118-127. doi:10.1577/A06-068.1
[6] Brown, L.L., Cox, W.T. and Levine, R.P. (1997) Evidence that the causal agent of bacterial cold-water disease Flavobacterium psychrophilum is transmitted within salmonids eggs. Diseases of Aquatic Organisms, 29, 213- 218. doi:10.3354/dao029213
[7] Evelyn, T.P.T., Ketcheson, J.E. and Prosperi-Porta, L. (1984) Further evidence for the presence of Renibacterium salmoninarum in salmonid eggs and the failure of povidone-iodine to reduce the intra-ovum infection rate in water-hardened eggs. Journal of Fish Diseases, 7, 173- 182. doi:10.1111/j.1365-2761.1984.tb00921.x
[8] Rangdale, R.E., Richards, R.H.J. and Alderman, D.J. (1997) Minimum inhibi-tory concentrations of selected antimicrobial compounds against Flavobacterium psychrophilum the causal agent of rainbow trout fry syndrome (RTFS). Aquaculture, 158, 193-201. doi:10.1016/S0044-8486(97)00202-0
[9] Dalsgaard, I., and Madsen, L. (2000) Bacterial pathogens in rainbow trout, Oncorhynchus mykiss (Walbuam), reared at Danish freshwater farms. Journal of Fish Diseases, 23, 199-209. doi:10.1046/j.1365-2761.2000.00242.x
[10] Bruun, M.S., Schmidt, A.S., Madsen, L. and Dalsgaard, I. (2000) Antimicro-bial resistance patterns in Danish isolates of Flavobacterium psychrophilum. Aquaculture, 187, 201-212. doi:10.1016/S0044-8486(00)00310-0
[11] Schmidt, A.S., Bruun, M.S., Dalsgaard, I., Pedersen, K. and Larsen, J.L. (2000) Occurrence of antimicrobial resistance in fish-pathogenic and environmental bacteria associated with four Danish rainbow trout farms. Applied and Environmental Microbiology, 66, 4908-4915. doi:10.1128/AEM.66.11.4908-4915.2000
[12] Kum, C., Kirkan, S., Sekkin, S., Akar, F. and Boyacioglu, M. (2008) Comparison of in-vitro antimicrobial susceptibility in Flavobacterium psychrophilum isolated from rainbow trout fry. Journal of Aquatic Animal Health, 20, 45-251. doi:10.1577/H07-040.1
[13] Hesami, S., Parkman, J., MacInnes, J.I., Gray, J.T., Gyles, C.L. and Lumsden, J.S. (2010) Antimicrobial susceptibility of Flavobacterium psychrophilum isolates from Ontario. Journal of Aquatic Animal Health, 22, 39-49. doi:10.1577/H09-008.1
[14] Watts, J.L., et al. (2010) Performance standards for antimicrobial disk and dilution susceptibility tests for bacteria isolated from animals; approved standard—3rd edition. Clinical and Laboratory Standards Institute, M31-A3, 28.
[15] Bruun, M.S., Madsen, L. and Dalsgaard, I. (2003) Efficiency of oxytetracycline treatment in rainbow trout experimentally infected with Flavobacterium psychrophilum strains having different in vitro antibiotic susceptibilities. Aquaculture, 215, 11-20. doi:10.1016/S0044-8486(01)00897-3
[16] Soltani, M., Shankar, S. and Munday, B.L. (1995) Chemotherapy of Cytophaga/Flexibacter-like bacteria (CFLB) infections in fish: Studies validating clinical efficacies of selected antimicrobials. Journal of Fish Diseases, 18, 555-565. doi:10.1111/j.1365-2761.1995.tb00360.x
[17] Bustos, P.A., Calbuyahue, J., Monta?a, J., Poazo, B., Entrala, P. and Solervicens, R. (1995) First isolation of Flexibacter psychrophilus, as causative agent of rainbow trout fry syndrome (RTFS), producing rainbow trout mortality in Chile. Bulletin of the European Association of Fish Pathologists, 15, 162-164.
[18] Weinstein, L. (1965) Antibiotics. II. Penicillin. In: Goodman, L.S. and Gilman, A., Eds., The Pharmacological Basis of Therapeutics, 3rd Edition, MacMillan Co., New York, 1193-1229.
[19] Donowicz, G.R. and Mandell, G.L. (1988). Beta-lactam antibiotics. New England Journal of Medicine, 318, 419- 426. doi:10.1056/NEJM198802183180706
[20] Austin, B. (1985) Evaluation of antimicrobial compounds for the control of bacterial kidney disease in rainbow trout, Salmo gairdneri Richardson. Journal of Fish Diseases, 8, 209-220. doi:10.1111/j.1365-2761.1985.tb01216.x
[21] US Pharmacopeial Convention (2007) Penicillin G.
[22] Lumsden, J.S., Ostland, V.E. and Ferguson, H.W. (1996) Necrotic myositis in cage cultured rainbow trout, Oncorhynchus mykiss (Walbaum), caused by Flexibacter psychrophilus. Journal of Fish Diseases, 19, 113-119. doi:10.1111/j.1365-2761.1996.tb00689.x
[23] Crump, E.M., Perry, M.B., Clouthier, S.C. and Kay, W.W. (2001) Antigenic characterization of the fish pathogen Flavobacterium psychrophilum. Applied and Environmental Microbiology, 67, 750-759. doi:10.1128/AEM.67.2.750-759.2001
[24] MacLean, L.L., Vinogradov, E., Crump, E.M., Perry, M.B. and Kay, W.W. (2001) The structure of the lipopolysaccharide O-antigen produced by Flavobacterium psychrophilum (259-93). European Journal of Biochemistry, 268, 2710-2716. doi:10.1046/j.1432-1327.2001.02163.x
[25] Cepeda, C., Gar-cia-Marquez, S. and Santos, Y. (2004) Improved growth of Flavobacterium psychrophilum using a new culture medium. Aquaculture, 238, 75-82. doi:10.1016/j.aquaculture.2004.05.013
[26] Wagner, E.J., Wilson, C., Arndt, R., Goddard, P., Miller, M., Hodgson, A., Vincent, R. and Mock, K. (2006) Evaluation of disease resistance of the Fish Lake-DeSmet, Wounded Man, and Harrison Lake strains of rainbow trout exposed to Myxobolus cerebralis. Journal of Aquatic Animal Health, 18, 128-135. doi:10.1577/H05-039.1
[27] Agresti, A. (1990) Categorical data analysis. Wiley and Sons, New York.
[28] Oppenheimer, C.H. (1955) The effect of marine bacteria on the development and hatching of pelagic fish eggs, and the control of such bacteria by antibiotics. Copeia, 1955, 43-49. doi:10.2307/1439451
[29] Peck, M.A., Buckley, L.J., O’Bryan, L.M., Davies, E.J. and Lapolla, A.E. (2004) Efficacy of egg surface disinfectants in captive spawning Atlantic cod Gadus morhua L. and haddock Melanogrammus aeglefinus L. Aqua-culture Research, 35, 992-996. doi:10.1111/j.1365-2109.2004.01119.x
[30] Arenzon, A., Lemos, C.A. and Bohrer, M.B.C. (2002) The influence of temperature on the embryonic development of the annual fish Cynopoecilus melanotaenia (Cyprinodontiformes, Rivulidae). Brazilian Journal of Biology, 62, 743-747. doi:10.1590/S1519-69842002000500002
[31] Jensen, J.P.T., McLean, W.E., and Alderdice, D.F. (1981) Effects of accessory factors on survival of newly fertilized salmonid eggs treated with an antibiotic. Aquaculture, 23, 295-307. doi:10.1016/0044-8486(81)90023-5
[32] Bruno, D.W. and Munro, A.L.S. (1986) Observations on Renibacterium salmoninarum and the salmonid egg. Diseases of Aquatic Or-ganisms, 1, 83-87. doi:10.3354/dao001083
[33] Evelyn, T.P.T., Ketcheson, J.E. and Prosperi-Porta, L. (1986) Use of erythromycin as a means of preventing vertical transmission of Renibacterium salmoninarum. Diseases of Aquatic Organisms, 2, 7-11. doi:10.3354/dao002007
[34] Barnes, M.E., Bergmann, D. Jacobs, J. and Gabel, M. (2009) Effect of Flavobacterium columnare inoculation, antibiotic treatments and resident bacteria on rainbow trout Oncorhynchus mykiss eyed egg survival and external membrane structure. Journal of Fish Biology, 74, 576-590. doi:10.1111/j.1095-8649.2008.02147.x
[35] Gee, L.L., and Sarles, W.B. (1942) The disinfection of trout eggs contaminated with Bacterium salmonicida. Journal of Bacteriology, 44, 111-126.
[36] Embrechts, E. (1982) Procaine peni-cillin toxicity in pigs. Veterinary Record, 111, 314. doi:10.1136/vr.111.14.314
[37] Blue, J.T., Dinsmore, R.P. and Anderson, K.L. (1987) Immune-mediated hemolytic anemia induced by penicillin in horses. Cornell Veterinarian, 77, 263-276.
[38] Nielsen, I.L., Jacobs, K.A., Huntington, P.J., Chapman, C.B. and Lloyd, K.C. (1988) Adverse reaction to procaine penicillin G in horses. Australian Veterinary Journal, 65, 181-185. doi:10.1111/j.1751-0813.1988.tb14296.x
[39] DeCew, M.G. (1972) Antibiotic toxicity, efficacy, and teratogenicity in adult spring Chinook salmon (Oncorhynchus tshawytscha). Journal of the Fisheries Research Board of Canada, 29, 1513-1517. doi:10.1139/f72-239
[40] Bullock, G.L. and Leek, S.L. (1986) Use of erythromycin in reducing vertical transmission of bacterial kidney disease. Veterinary and Human Toxicology, 28, 18-20.
[41] Brown, L.L., Albright, L.J. and Evelyn, T.P.T. (1990) Control of vertical transmission of Renibacterium salmoninarum by injection of antibiotics into maturing female coho salmon Oncorhynchus kisutch. Diseases of Aquatic Or-ganisms, 9, 127-131. doi:10.3354/dao009127
[42] Walter, W.M. and Vennes, J.W. (1985) Occurrence of multiple antibiotic resistance enteric bacteria in domestic sewage and oxidation ponds in Lagos. Applied and Environmental Microbiology, 50, 930-933.
[43] Ogbondeminu, F.S. and Olayemi, A.B. (1993) Antibiotic resistance in enteric bacterial isolates from fish and water media. Journal of Aquaculture in the Tropics, 8, 207-212.
[44] Payne, M.A., Craigmill, A., Riviere, J.E. and Webb, A.I. (2006) Extralabel use of penicillin in food animals. Journal of the American Veterinary Medical Association, 229, 1401-1403. doi:10.2460/javma.229.9.1401

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