Bacitracin
| Evidence Level: L5 | Predicted Indications: 10 |
Table of Contents
Bacitracin: From Keratitis to Punctate Epithelial Keratoconjunctivitis
One-Sentence Summary
Bacitracin is a polypeptide antibiotic originally used for eye infections such as keratitis, keratoconjunctivitis and blepharoconjunctivitis. The TxGNN model predicts it may be effective for punctate epithelial keratoconjunctivitis, but no clinical trials and no publications currently support this specific prediction.
Quick Overview
| Item | Content |
|---|---|
| Original Indication | Keratitis, keratoconjunctivitis, blepharoconjunctivitis (from the knowledge graph; the Singapore licence has no indication text) |
| Predicted New Indication | Punctate epithelial keratoconjunctivitis |
| TxGNN Prediction Score | 99.999% |
| Evidence Level | L5 |
| Singapore Market Status | ✓ Marketed |
| Number of Registrations | 1 |
| Recommended Decision | Hold |
Why is This Prediction Reasonable?
Currently, detailed mechanism of action data is not available. Based on known information, bacitracin is a topical polypeptide antibiotic. It is active mainly against gram-positive bacteria and is often combined with polymyxin B or neomycin. Its use in ocular infections is established, and mechanistically it may be applicable to bacterial forms of punctate epithelial keratoconjunctivitis.
The prediction is plausible mainly because the new condition sits very close to the existing ocular indications. However, punctate epithelial keratoconjunctivitis is often viral (for example adenoviral) or non-infectious, and an antibacterial would not be expected to help in those cases. The very high TxGNN score probably reflects this proximity in the knowledge graph rather than independent evidence.
Clinical Trial Evidence
Currently no related clinical trials registered.
Literature Evidence
Currently no related literature available for the top predicted indication.
For reference, a lower-ranked prediction, otitis externa (rank 4, evidence level L4), has indirect literature:
| PMID | Year | Type | Journal | Key Findings |
|---|---|---|---|---|
| 17503066 | 2007 | Double-blind clinical comparison | Eur Arch Otorhinolaryngol | 151 patients with acute bacterial otitis externa received a polymyxin B + bacitracin ointment with or without hydrocortisone acetate; this is a combination product, not bacitracin alone |
| 9820118 | 1998 | In vitro (veterinary) | Zentralbl Veterinarmed B | Antibiotic susceptibility of 46 bacterial isolates from chronic canine otitis externa, with increased resistance observed |
| 14055264 | 1963 | Review / practice article | Md State Med J | Practical treatment of otitis externa |
| 14048629 | 1963 | Clinical report | Z Laryngol Rhinol Otol | Local treatment of inflammatory ear conditions with a combination product (Nebacetin) |
Singapore Market Information
| Authorization Number | Product Name | Dosage Form | Approved Indication |
|---|---|---|---|
| SIN04413P | POLYBAMYCIN OINT. | Ointment | Not stated |
Safety Considerations
- Contraindications (knowledge graph associations, not package insert text): The data compiled for this report links bacitracin to the following conditions, which should be checked against the package insert:
- Eye conditions: herpes simplex virus keratitis, eye infectious disease, conjunctivitis, fungal eye infection, viral eye infection, open-angle glaucoma, ocular hypertension
- Kidney, liver and gallbladder disease
- Neuromuscular disorders: myasthenia gravis and neuromuscular junction disease
- Heart block (atrioventricular block)
- Diabetes mellitus and diabetic ketoacidosis
- Adrenocortical insufficiency (Addison disease)
- Epilepsy and respiratory failure
- Skin atrophy, telangiectasis and peripheral vascular disease
- Drug Interactions: 84 interactions were recorded. The major ones are with:
- Aminoglycosides: kanamycin, neomycin, streptomycin
- Deferasirox
- Iodinated contrast agents: diatrizoate, iodipamide, iodixanol, iohexol
Moderate interactions include mesalazine, balsalazide, olsalazine, sulfasalazine, vancomycin, exenatide and picosulfuric acid.
- Systemic use: Bacitracin is nephrotoxic when used systemically, which matters for several lower-ranked predictions involving renal disease.
Package insert warnings and contraindications were not available. Please refer to the package insert for authoritative safety information.
Conclusion and Next Steps
Decision: Hold
Rationale: The prediction is biologically plausible because it sits next to bacitracin's existing ocular uses, but it is supported only by model output (L5). No trials or literature were found, and many cases of this condition are viral or non-infectious, where an antibacterial is unlikely to help.
Other predictions fall into three groups:
- Otitis externa has only indirect, mostly combination-product evidence (L4) and could be a research question.
- Exposure keratitis is conceptually plausible as prophylaxis but unsupported by evidence.
- The remaining predictions (non-human animal disease, post-infectious conditions, infection-related hemolytic uremic syndrome, Chagas cardiomyopathy, urethral stricture) lack a mechanistic basis. For infection-related hemolytic uremic syndrome the prediction also carries potential harm.
To proceed, the following is needed:
- Singapore package insert warnings and contraindications (from the HSA website)
- Mechanism of action data
- Clinical evidence on the aetiology of punctate epithelial keratoconjunctivitis (bacterial vs viral) and on the efficacy of topical bacitracin
- Confirmation of the approved indication and active ingredients of the registered ointment (POLYBAMYCIN OINT.), whose indication text is blank
- Safety review of the contraindication associations, especially for ocular herpes and viral eye infection
Disclaimer
This content is for research purposes only and does not constitute medical advice. Clinical validation is required before any clinical application.