Creative Biolabs provides research-use phage host-range determination service to help investigators define how candidate phages respond across a selected bacterial host panel. We support host panel design, spot or microplate screening, plaque confirmation when needed, EOP follow-up, and matrix-based reporting with clear interpretation limits.
Host range is not an absolute property measured once for all contexts. It depends on panel composition, bacterial growth conditions, phage preparation, readout type, and which infection step the assay measures. Our service is designed to distinguish lysis indication, plaque formation, and productive infection so that the final matrix is useful for downstream research planning.
Researchers request host-range determination when they need to compare phage coverage across a host panel, select candidate phages for additional characterization, or understand whether response patterns are broad, narrow, or strain-specific. Our service is especially useful when sample sources, host diversity, and downstream decision points vary.
Our host-range studies are built around a defined bacterial panel, with initial screening formats—including spot tests, square-plate layouts, or microplates—tailored to your specific needs. We ensure experimental accuracy by incorporating typed-phage controls, clear response categories, and relevant sample sources (such as fermentation broth, air, sewage, or soil) directly into the study design.
Useful for rapid panel-level observation of lysis or clearing patterns.
Helps separate true plaque formation from nonproductive clearing or lysis from without.
Supports semi-quantitative comparison across susceptible hosts when countable plaques are available.
Reports distinguish adsorptive, bactericidal, productive, plaquing, spotting, or lysogenic-related observations when supported.
Hosts are grouped by species, strain, source, or research question.
Candidate phages are reviewed for titer, buffer, and handling needs.
Spot or microplate screening is performed according to the agreed format.
Selected responses can be confirmed by plaque assay where interpretation requires it.
Susceptible hosts can be compared by efficiency of plating when countable plaques allow.
Results are summarized with categories, images or notes, and limitations.
Useful inputs include candidate phage, host strain list and metadata, preferred screening format, expected grouping level, replicate plan, sample source if relevant, and any typed phages or reference controls. Creative Biolabs can also help build a staged panel when the full strain list is not yet available.
| Deliverable | What It Helps Answer |
|---|---|
| Host-by-phage matrix | Which hosts show response under the tested conditions? |
| Spot or plaque notes | Was the observation clear, weak, plaque-forming, or ambiguous? |
| EOP table | How efficiently does the phage plaque on selected susceptible hosts? |
| Interpretation limits | Which conclusions are panel- and method-dependent? |
QC planning includes host viability and lawn quality, typed-phage or reference controls, replicate spot or plaque consistency, dilution traceability, EOP countability, and documentation of method-dependent discrepancies. We avoid reporting a broad host-range claim when the tested panel is narrow or confirmation data are limited.
The workflow can be customized around host panel breadth, strain metadata, square-plate or microplate format, spot-test layout, plaque assay confirmation, EOP calculation, typed-phage controls, replicate plan, and response-category definitions. The final scope is agreed before sample processing.
Ready to plan the next experiment? Send us the host/phage information you already have, and we will help define a research-use workflow, data package, and reporting scope that fit your project.
A 2018 Viruses study developed a liquid culture-based 96-well microtiter plate assay to measure bacteriophage host range and virulence for 15 Salmonella phages across 20 Salmonella strains representing 11 serovars. The authors compared the microplate approach with traditional spot testing and reported broad agreement for many host-range outcomes, while showing how liquid-format readouts can support higher-throughput comparison across phage-host panels. This paper supports matrix-based planning, replicate design, and careful distinction between clearing, growth inhibition, plaque formation, and productive infection. The study does not remove the need for plaque confirmation or EOP follow-up when a project requires stronger interpretation.
This literature discussion is included as method background only. It does not represent a guarantee of project outcome, recovery, virulence, or host-range behavior in a client-specific study.
Fig.1 Microtiter plate host-range matrix for Salmonella phage-host screening.1
Q: What information is needed to start a Phage Host-Range Determination project?
A: We usually need the candidate phage, host strain list, strain metadata, preferred assay format, replicate expectations, and any reference controls. We can help stage the panel if the host list is still being built.
Q: Can the Phage Host-Range Determination workflow be customized?
A: Yes. We can adjust host panel breadth, spot or microplate format, plaque confirmation, EOP follow-up, replicate design, typed-phage controls, and response-category reporting.
Q: What deliverables are included?
A: We typically provide a host-by-phage response matrix, scoring legend, spot or plaque notes, EOP table when included, and interpretation limits for the tested panel.
Q: How are quality checks handled?
A: We review host growth, lawn quality, control behavior, replicate consistency, dilution traceability, and EOP countability. Ambiguous spots can be repeated or moved to plaque confirmation.
Q: Is spot clearing the same as productive infection?
A: No. Spot clearing may reflect several mechanisms, including nonproductive effects. Plaque formation and EOP testing provide stronger evidence when productive infection needs to be assessed.
Q: How can I discuss a nonstandard host-range project?
A: Send the host panel, phage information, sample source, and desired response categories. We will suggest a screening and confirmation plan aligned with your research goal.
Reference:
Please kindly note that our services can only be used to support research purposes (Not for clinical use).
Creative Biolabs is a globally recognized phage company. Creative Biolabs is committed to providing researchers with the most reliable service and the most competitive price.
