Detection and treatment of bacterial kidney disease (BKD)
was investigated. Experiments were conducted to evaluate the
quantitative, fluorescent antibody technique (QFAT) that is used
to detect, identify, and quantify both typical and 'bar form'
Renibacterium salmoninarum cells. Smears of kidney tissue from
naturally and artificially infected salmonids, both with and
without chemotherapy, were quantitatively examined throughout
the course of R. salmoninarum infections. Detection and
quantification by QFAT has been reported to provide assessments
of prevalence and severity of R. salmoninarum of individual fish.
These assessments and the occurrence of 'bar forms' of R.
salmoninarum have been used as an indication of recovery within
a population. 'Bar forms' were observed in kidney tissue smears
of fish that survived bacterial challenge when treated with
erythromycin. The 'bar form' was also detected when rainbow
trout were artificially infected with lower doses of live R .
salmoninarum and in fish that were injected with irradiation-inactivated
R. salmoninarum cells. By examining R. salmoninarum
cultures in vitro by QFAT, it was determined that 'bar forms' did
not occur on artificial media even when antibiotics were
incorporated into the agar. When QFAT was compared to direct
fluorescent antibody technique (DFAT) and quantitative enzyme
linked immunosorbent assay (ELISA), it was determined that
QFAT had similar sensitivity as ELISA but was more sensitive
than DFAT. QFAT was also used to predict minimum mortality.
Experiments were also conducted to evaluate drug regimes
to treat both artificial and natural R. salmoninarum infections.
Erythromycin was administered by intraperitoneal injection in
different doses and at selected days post infection. Erythromycin
decreased percent mortality and increased mean day to death, but
did not completely eradicate R. salmoninarum from infected test
animals. Sarafloxacin and erythromycin were incorporated into
daily ration of artificially infected test animals. Contrary to
erythromycin, sarafloxacin did not decrease mortality or increase
mean day to death when tested in vivo against R. salmoninarum.
A new drug, A-77143, was tested in vitro to determine if it was
bactericidal and its minimum inhibitory concentration. When A-
77143 was compared to other antibiotics, it had a relatively low
minimum inhibitory concentration and was shown to be
bactericidal against the eight strains of R. salmoninarum tested. / Graduation date: 1993
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/36464 |
| Date | 17 December 1992 |
| Creators | Drongesen, Jeffrey Edward |
| Contributors | Rohovec, John S. |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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