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C. E. Starliper

Publications and source records attributed to C. E. Starliper.

At least 37 records · Page 2Linked to original sources
USGS1998

Windrow composting as an effective method to dispose of large numbers of fish

During July 1998, at the USGS Leetown Science Center, Kearneysville, West Virginia, an epizootic occurred in 16-month-old Atlantic salmon (Salmo salar). The cause ofmortality was diagnosed as furunculosis, a serious disease in salmonid fishes caused by the bacterium Aeromonas salmonicida. The fish were being maintained as part ofongoing research and were held in uncovered 30-m-Iong concrete raceways, each supplied with about 757 L per minute of 12 ?C pathogen-free spring water. The means by which the fish became infected could not be determined, and there was no recent history offurunculosis in the hatchery system.

Biological Information and Technology Notes↗
USGS1998

Performance of serum-free broth media for growth of Renibacterium salmoninarum

Growth of Renibacterium salmoninarum was compared in 14 different broth media; 13 serum-free, and 1 that contained newborn calf serum, KDM2+M. Supplementation with 1% v/v R. salmoninarum MCO4M metabolite was evaluated for 6 of the media that do not utilize it as part of their ingredients. Viable cells were enumerated on Days 10, 20, and 30 post inoculation to evaluate performance. The experiment was repeated 3 times using high, low, and medium (trials 1 to 3, respectively) cell concentrations as inoculum. In general there was no optimal medium and all performed well. The choice of which to employ depends on the ease of preparation and presence of certain ingredients that might affect subsequent assays. In trials 2 and 3, the pH was estimated using test papers at the same time as cells were counted. Maximum pH increase occurred with KDM2+M and those media containing charcoal. For most media, a simple pH determination could be used as a means to check that growth has occurred in a culture, particularly if charcoal was added directly to the media and a visual inspection could not be made to detect growth.

Diseases of Aquatic Organisms↗
USGS1997

Virulence of Renibacterium salmoninarum to salmonids

Virulence of Renibacterium salmoninarum isolates representing five origins was evaluated in eight salmonid hosts; four origins were of Lake Michigan and the fifth was of the Pacific Northwest. The species type strain, ATCC (American Type Culture Collection) 33209, was also included. Each isolate was grown in a kidney disease medium (KDM2) supplemented with 1 % ATCC 33209 culture metabolite; serial 10-fold dilutions were prepared, and groups of fish were challenged by intraperitoneal injection with 0.1 mL of each dilution. A 70-d observation period followed, and bacterial kidney disease (BKD) was diagnosed by the fluorescent antibody technique. Virulence of isolates was quantified as a dose lethal to 50% of fish (LD50) for each host–isolate challenge. In the first set of experiments, 23 isolates were used to challenge groups of brook trout Salvelinus fontinalis. The mean LD50 was 1.087 x 10 6 colony-forming units per milliliter (cfu/mL; SD = 2.022 x 10 6 ), and the LD50 values ranged from 8.457 x 10 6 to 2.227 x 10 4 cfu/mL. Analysis of variance to evaluate the effect of isolate origin on virulence in brook trout revealed no significant difference ( F = 1.502; P = 0.243). Susceptibilities of the other salmonid hosts were evaluated by challenge with six isolates of R. salmoninarum representing each origin and the species type strain. For many of the host–isolate challenge combinations, time to death was highly dependent on the dilution (number of bacteria) injected. In general, the isolates MCO4M, B26, and A34 (all of Lake Michigan origin) tended to be more virulent. Also, LD50 values were dispersed throughout a wider range among the more susceptible hosts. Lake trout Salvelinus namaycush, rainbow trout Oncorhynchus mykiss, and brook trout were relatively resistant to challenge with the strains, whereas coho salmon O. kisutch, domestic Atlantic salmon Saltno salar, and chinook salmon O. tshawytscha were relatively susceptible. Another challenge evaluated the effect of washing R. salmoninarum MCO4M cells before injection into brook trout. The calculated LD50 value, 2.009 x 10 5 cfu/mL, was similar ( X 2 = 0.878; P = 0.645) to that of the unwashed cells (1.163 x 10 5 cfu/mL). Furthermore, times to death for successive dilutions were similar regardless of whether or not the cells were washed.

Journal of Aquatic Animal Health↗
USGS1996

Control of external Aeromonas salmonicida: topical disinfection of salmonids with Chloramine-T

Brook trout Salvelinus fontinalis were treated with single 60-min static baths of 250 mg formalin/L, 3% NaCl, and 15 mg Chloramine-T/L to evaluate the efficacy of these compounds against external infections of Aeromonas salmonicida. Prevalence of A. salmonicida was significantly lower in brook trout treated with Chloramine-T than among those treated with formalin or salt. Further laboratory tests substantiated the therapeutic value of a single treatment of ChloramineT (15 mg/L) against A. salmonicida . In two experiments, viable counts of A. salmonicida in mucus did not vary among replicate groups of treated brook trout, but the counts for treated fish were significantly (P < 0.05) lower than those for untreated controls. In vitro tube dilution assays indicated that mean minimum inhibitory concentrations of Chloramine-T for 10 isolates of A. salmonicida were 9.0 mg/L for 1 h and 2.25 mg/L, for 24 h. In field trials at the White River National Fish Hatchery (Bethel, Vermont), the pathogen was detected principally as an external infection of juvenile Atlantic salmon Salmo solar maintained in two culture ponds. In one pond, the bacterium accounted for 100% of the total distribution of tnicroflora isolated from mucus. Seven days after treatment with Chloramine-T, A. sahnonicida accounted for 11% of the total bacterial counts identified from these fish. In the second pond, A. salmonicida composed 3% of the counts of bacteria isolated from the mucus of fish before treatment but was not isolated after treatment.

Journal of Aquatic Animal Health↗
USGS1996

Genetic diversity of North American isolates of Renibacteriumsalmoninarum

Genetic diversity of Renibacterium salmoninarum was evaluated by multilocus enzyme electrophoresis (MEE). Whole cell lysates were prepared for 40 isolates representing 5 groups based on host and geographic area. Each lysate was assessed for activity of 44 enzymes with a pH 6.5 amine-citrate and a pH 8.0 buffer. Genetic variation was scored at 26 loci. Two zones of activity (presumptive loci) were scored each for esterase (EC 3.1.1.1) and glycyl-leucine peptidase (EC 3.4.11.x). There were no monomorphic loci and there was an average of 2.65 electromorphs per locus. There were 21 electrophoretic types. Mean genetic diversity ( H T ) was 0.161 and the percentage of this explained by diversity between groups was G st = 8.1%; thus 91.9% of the genetic diversity was due to heterogeneity between individual isolates. The 2 groups with the highest genetic diversity were from chinook Oncorhynchus tshawytscha and coho O . kisutch salmon, both from the Manistee Weir, Michigan, USA; i.e. 0.270 and 0.298, respectively. The highest genetic diversity for a locus ( h T ) was 0.587 for EST-1. At this locus, diversity between groups explained a higher percentage of the total diversity ( G st = 36.5%). Other loci with relatively high genetic diversity were succinate dehydrogenase (0.385; EC 1.3.99.1), cytochrome c oxidase (0.273; EC 1.9.3.1) and aconitase (0.311; EC 4.2.1.3). The results of this study indicate relatively low genetic diversity of R . salmoninarum .

Diseases of Aquatic Organisms↗
USGS1993

Plasmid-mediated romet resistance of Edwardsiella ictaluri

Romet®, a potentiated sulfa drug composed of five parts sulfadimethoxine and one part ormetoprim, is used to treat channel catfish Ictalurus punctatus infected with Edwardsiella ictaluri , the causal agent of enteric septicemia of catfish (ESC). Recently, several Romet-resistant isolates of E. ictaluri were isolated from channel catfish that had died from ESC in Virginia and Mississippi. This antimicrobial resistance was determined to be plasmid-encoded, as shown by agarose gel electrophoresis of plasmid DNA, and by the fact that the plasmid and associated antimicrobial resistance could be transferred to a recipient by single-step conjugation. Size of the R plasmid was approximately 55 kilobase pairs. Plasmids also conferred resistance to tetracycline, oxytetracycline, streptomycin, trimethoprim, and SXT (another potentiated sulfonamide, composed of trimethoprim and sulfamethoxazole). Each Romet-resistant E. ictaluri isolate was mated with a plasmid recipient, the Romet-sensitive Escherichia coli isolate 1932. Transconjugates were selected by plating on Mueller-Hinton agar that contained antimicrobials, and the mean transfer frequency was 1.483 × 10 −3 transconjugates per donor cell in the mating mixture. Each E. coli transconjugate was then mated with 20 Romet-sensitive isolates of E. ictaluri to assess the propensity of these E. ictaluri isolates to accept the R plasmid. The average transfer frequency when E. ictaluri isolates of channel catfish origin (N = 14) were used as recipients was 1.197 × 10 −2 transconjugates per donor cell in the mating mixture; mean transfer frequency when E. ictaluri isolates not originating from channel catfish were used was 1.019 × 10 -3 transconjugates per donor cell, which was significantly less (P = 0.0002).

Journal of Aquatic Animal Health↗