Control of vertical transmission of Renibacterium salmoninarum by injection of antibiotics into maturing female coho salmon Oncorhynchus kisutch

Abstract

A study was conducted to evaluate the levels of drugs attained In eggs and alevlns as a result of injecting antibiotics lnto pie-spawning female salmon Oncoihynchus kisutcli and to evaluate i f thls was a n effechve means of controlling vertical transmission of Renlbacterium s a l n~o n~n a r u m (Rs) the causative agent of bactenal kldney disease Flve antibiotics (erythromycin phosphate penicillin G ovytetracychne cephradine and rifampicin) were ~njected into the dorsal slnus of maturing female coho salmon, one antibiotic per fish 2 to 3 wk before spawnlng Eggs from these fish were then infected ~nternally with Rs using a microinjectlon technique The prevalence of the resulting infechons was determned for the eggs at the eyed stage and for alevlns at hatch Concentrations of each antiblotlc were measured in the egg yolk at spawning and in the alemns at hatch All 5 antibiohcs were detected in eggs taken at spawning but only erythromycin and nfampicln were present in measurable amounts ~n t h i n the alevins at hatch The 5 antibiotics all proved to b e effective in significantly reducing the prevalence of Rs infections by the hatch stage The broodstock injection technique therefore appears to be a promising means of reducing the vertical transmission of Rs

Comparison of the Membrane-Filtration Fluorescent Antibody Test, the Enzyme-Linked Immunosorbent Assay, and the Polymerase Chain Reaction to Detect Renibacterium Salmoninarum in Salmonid Ovarian Fluid

“…Autolysis may occur in ovarian fluids from fish in which bacterial replication had ceased early during sexual maturation; the fish used in this study were injected with erythromycin to reduce vertical transmission of R. salmoninarum. 4,15 In addition, p57 protein degradation increases at higher, (nonphysiological) temperatures, 18,37 and the heating step of sample preparation for the ELISA may cause a transient degradation that is most evident for samples with lower bacterial levels.…”

Comparison of the enzyme-linked immunosorbent assay (ELISA) and the fluorescent antibody test (FAT) for measuring the prevalences and levels of Renibacterium salmoninarum in wild and hatchery stocks of salmonid fishes in Alaska. USA

“…In addition to a water supply free of Rs, avoidance has largely been attempted by using eggs from certified Rs-free fish stocks or by manipulation of Rs-positive broodstocks to reduce vertical transmission to the progeny. One such manipulation has been injection of antibiotics into maturing female broodfish producing an accumulation of therapeutic drug levels in the yolk of the embryo (Groman & Klontz 1983, Bullock & Leek 1986, Evelyn et al 1986a, Armstrong et al 1989a, Brown et al 1990). Another alternative has been the elimination or segregation of eggs and fry spawned from Rs-positive parents (Pascho et al 1991).…”

MICs and MBCs of chemotherapeutic agents against Renibacterium salmoninarum

“…Recently, Brown et al (7) evaluated the efficacy of five antibiotics (erythromycin, penicillin G, oxytetracycline, cephradine, and rifampin) by the prespawning injection of the drugs into female brood salmon. Although all five drugs, especially cephradine and rifampin, proved to be effective in significantly reducing the prevalence of R. salmoninarum infections by the hatch stage, no antibiotic was able to eliminate the pathogen from all the eggs or alevins.…”