Strain characterization, antimicrobial susceptibility and cold-induced genes of Flavobacterium psychrophilum
Bibliographic record
Abstract
Seventy-five isolates of 'Flavobacterium psychrophilum' collected from salmonids with clinical signs of bacterial cold water disease (BCWD) were characterized morphologically, biochemically, serologically, and genotypically. Although the isolates were morphologically and serologically homogeneous, API-ZYM testing revealed two distinct biovars. Four restriction pattern types were detected by 16S rRNA PCR-RFLP analysis. There were significant correlations between biovar I and digestion with 'Mae'III (' p'<0.001) and between biovar II and digestion with 'Mnl 'I ('p'<0.05). Detection of nine genotypes within a 194 bp region of 16S sequence type revealed further heterogeneity of which type "a" was the predominant genotype. More than one biovar and genotype was identified among the strains recovered from a single BCWD outbreak, however, no association between genotype or biotype and clinical disease presentation was found. Management of outbreaks of BCWD often requires the use of antibiotics. The minimal inhibitory concentrations (MICs) of 10 antimicrobial agents were determined by adapting a broth microdilution method established by the Clinical and Laboratory Standards Institute for aquatic bacteria with optimal growth temperature below 35°C. For most 'F. psychrophilum' isolates there was a very high MIC for two of the four antibiotics licensed for use in Ontario (i.e., ormetoprim/sulfadimethoxine and trimethoprim/sulfamethoxazole). High MICs of florfenicol and oxytetracycline were obtained for 53% and 61% of isolates, respectively. For the majority of strains, the MICs for ampicillin, oxolinic acid and gentamicin were high, while for 83% of the strains tested the MICs for erythromycin were medium and low. cDNA suppression subtractive hybridization (SSH) was used to identify cold-induced genes in a ulcerative dermatitis and necrotizing stomatitis isolate ' F. psychrophilum' B382-90-4. Genes predicted to encode a two-component system sensor histidine kinase LytS, an ATP-dependent RNA helicase, a multidrug ABC transporter permease/ATPase, an outer membrane protein/protective antigen OMA87, an M43 cytophagalysin zinc-dependent metalloprotease, a hypothetical protein and four housekeeping genes, were up-regulated at 8°C versus 20°C. Since no reference gene of 'F. psychrophilum' was available as an internal standard for use in quantitative real-time PCR (qPCR), the expression stability of 9 commonly used reference genes was evaluated at 8°C and 20°C. Expression of the 16S rRNA gene was equivalent at both temperatures and this gene was used in qPCR experiments to verify the SSH findings.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".