Nasal and Pharyngeal MicrobiomePhase 2NCT05287425
The Effect of Antibiotic Eye Drops on the Nasal Microbiome in Healthy Subjects
A Phase 2 study testing Gentamicin Ophthalmic, Ciprofloxacin Ophthalmic and Povidone Ophthalmic in people with Nasal and Pharyngeal Microbiome, run by Medical University of Vienna at 1 site in Austria.
Trial summary
Ophthalmic topical antibiotics are commonly prescribed in clinical practice for several indications such as bacterial conjunctivitis, keratitis, blepharitis, dacryocystitis and also as prophylaxis. Aminoglycosides (i.e. gentamicin) and fluoroquinolones (i.e. Read more about this study
- Who is it for?
- Ages 18 to 45 yearsHealthy volunteers can take part
- Conditions the study is for
- Nasal and Pharyngeal Microbiome
- What is being tested?
- Gentamicin Ophthalmic, Ciprofloxacin Ophthalmic and Povidone Ophthalmic
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 20 participants
- Where
- 1 siteAustria
- Study dates
- 12 Aug 2019to 28 Aug 2023
- Phase
- Phase 2
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 45 years
- All sexes
- Healthy volunteers accepted
- Adult
Who may be able to join
- Men and women aged between 18 and 45 years
- Normal ophthalmic findings
- Tear Break Up Time >10 seconds
- Schirmer I Test > 10mm/5min
- Ametropia ≤ 6 diopters
- No use of topical eye or nasal drops in the last 3 months
Who cannot join
- Regular use of medication, abuse of alcoholic beverages or drugs
- Participation in a clinical trial in the 3 weeks preceding the study
- Treatment in the previous 3 weeks with any drug (except intake of hormonal contraceptives)
- Treatment with topical or systemic antibiotics within 8 weeks before inclusion
- Symptoms of a clinically relevant illness in the 3 weeks before the first study day
- History or presence of gastrointestinal, liver or kidney disease, or other conditions known to interfere with distribution, metabolism or excretion of study drugs
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- Known hypersensitivity to any of the components of the IMP under investigation or other study medication
- Pregnant or breast-feeding women
- Women of childbearing potential (neither menopausal, nor hysterectomized, nor sterilized) not using effective contraception (i.e. oral contraceptives, intra-uterine device, contraceptive implant or condoms)
Trial locations and contacts
1 site in 1 country.
Austria1 site
Department of Clinical Pharmacology, Medical University of Vienna
Vienna, State of Vienna, 1090
About this study
Official title: The Effect of Antibiotic Eye Drops on the Nasal Microbiome in Healthy Subjects, a Phase II Study
Ophthalmic topical antibiotics are commonly prescribed in clinical practice for several indications such as bacterial conjunctivitis, keratitis, blepharitis, dacryocystitis and also as prophylaxis. Aminoglycosides (i.e. gentamicin) and fluoroquinolones (i.e. ciprofloxacin) are among the most frequently used substance classes.
There is evidence that topical non-antibiotic eye drops might have an effect on the nasopharyngeal mucosal flora. This seems logical due to the anatomical connection through the nasolacrimal duct and the fact that up to 80% of topically administered drug diffuse into the systemic circulation through the highly vascularized nasopharyngeal mucosa. However, in the literature no data on the effect of antibiotic eye drops on the nasal or pharyngeal microbiome are currently available.
Read more
Recently, new, non-culture based techniques for assessment of the bacterial microbiome have been developed, so-called "next-generation sequencing" (NGS). NGS utilizes universal primers targeting the 16S rRNA gene, which is ubiquitous across most bacteria. With this technique, it is possible to gain information about a wide range of the bacterial microbiome and not only on pre-selected species.
In the present study, NGS will be used to investigate the effect of antibiotic eye drops on the nasal and pharyngeal microbiome. For this purpose, healthy subjects will be randomized to either receive eye drops containing gentamicin, ciprofloxacin or topical lubricants as control. As secondary outcome, prevalence of bacterial resistance genes, as well as signs and symptoms of ocular surface damage will be assessed.
The study will be carried out in 2 parts. Since both formulations of topical antibiotics contain benzalkonium chloride which also has a potential effect on the nasal and pharyngeal mucosal flora, it is unknown how much benzalkonium chloride would contribute to changes in the nasal microbiome after administration of topical antibiotics. To overcome this problem, first a pilot study in 20 subjects will be performed in which subjects will be randomized to receive either eye drops containing gentamicin, ciprofloxacin, preservative-containing topical lubricants or preservative-free topical lubricants. Based on the results of this pilot study, the control for the main part of the study will be chosen, depending on the effect on the bacterial microbiome. The results of the pilot study could also provide useful data to adjust the sample size for the main study part. In the main study, 60 subjects will be randomized to receive gentamicin, ciprofloxacin or lubricant eye drops. The same examinations as described above will be performed after 1 week treatment as well as 1 week and 3 months after treatment.
- Conditions
- Nasal and Pharyngeal Microbiome
- Being tested
- Gentamicin Ophthalmic, Ciprofloxacin Ophthalmic, Povidone Ophthalmic, Povidone and Benzalkonium Chloride Ophthalmic
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Gentamicin OphthalmicDrug
4 drops daily in both eyes for 7 ± 1 days
Ciprofloxacin OphthalmicDrug
4 drops daily in both eyes for 7 ± 1 days
Povidone OphthalmicDrug
4 drops daily in both eyes for 7 ± 1 days
Povidone and Benzalkonium Chloride OphthalmicDrug
4 drops daily in both eyes for 7 ± 1 days
| Study group | Role | What they receive |
|---|---|---|
| Gentamicin eye drops | Experimental | 4 drops daily in both eyes for 7 ± 1 days Receives: Drug: Gentamicin Ophthalmic |
| Ciprofloxacin eye drops | Experimental | 4 drops daily in both eyes for 7 ± 1 days Receives: Drug: Ciprofloxacin Ophthalmic |
| Povidone eye drops unpreserved | Active comparator | 4 drops daily in both eyes for 7 ± 1 days Receives: Drug: Povidone Ophthalmic |
| Povidone eye drops preserved | Active comparator | 4 drops daily in both eyes for 7 ± 1 days Receives: Drug: Povidone and Benzalkonium Chloride Ophthalmic |
What is being measured
The primary outcome is the main question the study is designed to answer.
Nasal bacterial microbiome
16S rRNA gene sequencing
Measured: change after 1 week treatment
Secondary outcomes (4)
Pharyngeal bacterial microbiome
16S rRNA gene sequencing
Measured: change after 1 week treatment
Antibiotic resistance gene prevalence
Measured: change after 1 week treatment
Minimum inhibitory concentrations for gentamicin and ciprofloxacin
Measured: change after 1 week treatment
Tear film thickness
Measured: change after 1 week treatment
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted18 Mar 2022
- Study start12 Aug 2019
- Primary completion28 Aug 2023
- Study completion28 Aug 2023
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Nasal and Pharyngeal MicrobiomeStudies of the same condition, open and under way.
- More trials run by Medical University of ViennaThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 2
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Double blind
- Who is masked
- Investigator, Outcomes assessor
- Enrolment
- 20 participants (actual)
Sponsor and investigators
- Lead sponsor
- Medical University of Vienna
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Doreen Schmidl, Medical University of Vienna
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05287425
- Sponsor's protocol ID
- OPHT-240518
- Status last verified
- Mar 2023
- First submitted
- 29 Dec 2021
- Last updated
- 16 May 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 16 May 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- The Effect of Antibiotic Eye Drops on the Nasal Microbiome in Healthy Subjects, a Phase II Study
- ClinicalTrials.gov ID
- NCT05287425
- Acronym / sponsor ID
- OPHT-240518
- Conditions
- Nasal and Pharyngeal Microbiome
- Phase
- Phase 2
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 20 participants (actual)
- Lead sponsor
- Medical University of ViennaUniversity, hospital or other
- Study start
- 12 Aug 2019 (actual)
- Primary completion
- 28 Aug 2023 (actual)
- Study completion
- 28 Aug 2023 (actual)
- First posted
- 18 Mar 2022 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Ophthalmic topical antibiotics are commonly prescribed in clinical practice for several indications such as bacterial conjunctivitis, keratitis, blepharitis, dacryocystitis and also as prophylaxis. Aminoglycosides (i.e. gentamicin) and fluoroquinolones (i.e. ciprofloxacin) are among the most frequently used substance classes.
There is evidence that topical non-antibiotic eye drops might have an effect on the nasopharyngeal mucosal flora. This seems logical due to the anatomical connection through the nasolacrimal duct and the fact that up to 80% of topically administered drug diffuse into the systemic circulation through the highly vascularized nasopharyngeal mucosa. However, in the literature no data on the effect of antibiotic eye drops on the nasal or pharyngeal microbiome are currently available.
Recently, new, non-culture based techniques for assessment of the bacterial microbiome have been developed, so-called "next-generation sequencing" (NGS). NGS utilizes universal primers targeting the 16S rRNA gene, which is ubiquitous across most bacteria. With this technique, it is possible to gain information about a wide range of the bacterial microbiome and not only on pre-selected species.
In the present study, NGS will be used to investigate the effect of antibiotic eye drops on the nasal and pharyngeal microbiome. For this purpose, healthy subjects will be randomized to either receive eye drops containing gentamicin, ciprofloxacin or topical lubricants as control. As secondary outcome, prevalence of bacterial resistance genes, as well as signs and symptoms of ocular surface damage will be assessed.
The study will be carried out in 2 parts. Since both formulations of topical antibiotics contain benzalkonium chloride which also has a potential effect on the nasal and pharyngeal mucosal flora, it is unknown how much benzalkonium chloride would contribute to changes in the nasal microbiome after administration of topical antibiotics. To overcome this problem, first a pilot study in 20 subjects will be performed in which subjects will be randomized to receive either eye drops containing gentamicin, ciprofloxacin, preservative-containing topical lubricants or preservative-free topical lubricants. Based on the results of this pilot study, the control for the main part of the study will be chosen, depending on the effect on the bacterial microbiome. The results of the pilot study could also provide useful data to adjust the sample size for the main study part. In the main study, 60 subjects will be randomized to receive gentamicin, ciprofloxacin or lubricant eye drops. The same examinations as described above will be performed after 1 week treatment as well as 1 week and 3 months after treatment.
Study design
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Double blind (investigator, outcomes assessor)
- Number of arms
- 4
| Arm | Type | Receives |
|---|---|---|
| Gentamicin eye drops | Experimental | Drug: Gentamicin Ophthalmic4 drops daily in both eyes for 7 ± 1 days |
| Ciprofloxacin eye drops | Experimental | Drug: Ciprofloxacin Ophthalmic4 drops daily in both eyes for 7 ± 1 days |
| Povidone eye drops unpreserved | Active comparator | Drug: Povidone Ophthalmic4 drops daily in both eyes for 7 ± 1 days |
| Povidone eye drops preserved | Active comparator | Drug: Povidone and Benzalkonium Chloride Ophthalmic4 drops daily in both eyes for 7 ± 1 days |
Who may qualify
- Ages
- 18 to 45 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (6 listed)
- Men and women aged between 18 and 45 years
- Normal ophthalmic findings
- Tear Break Up Time >10 seconds
- Schirmer I Test > 10mm/5min
- Ametropia ≤ 6 diopters
Key exclusion criteria (9 listed)
- Regular use of medication, abuse of alcoholic beverages or drugs
- Participation in a clinical trial in the 3 weeks preceding the study
- Treatment in the previous 3 weeks with any drug (except intake of hormonal contraceptives)
- Treatment with topical or systemic antibiotics within 8 weeks before inclusion
- Symptoms of a clinically relevant illness in the 3 weeks before the first study day
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Gentamicin Ophthalmic4 drops daily in both eyes for 7 ± 1 days | Drug | Gentamicin eye drops |
| Ciprofloxacin Ophthalmic4 drops daily in both eyes for 7 ± 1 days | Drug | Ciprofloxacin eye drops |
| Povidone Ophthalmic4 drops daily in both eyes for 7 ± 1 days | Drug | Povidone eye drops unpreserved |
| Povidone and Benzalkonium Chloride Ophthalmic4 drops daily in both eyes for 7 ± 1 days | Drug | Povidone eye drops preserved |
Primary outcome
Nasal bacterial microbiome
Time frame: change after 1 week treatment
16S rRNA gene sequencing
4 secondary outcomes
Pharyngeal bacterial microbiome
Time frame: change after 1 week treatment
Antibiotic resistance gene prevalence
Time frame: change after 1 week treatment
Minimum inhibitory concentrations for gentamicin and ciprofloxacin
Time frame: change after 1 week treatment
Tear film thickness
Time frame: change after 1 week treatment
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 16 May 2025.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 2 study testing Gentamicin Ophthalmic, Ciprofloxacin Ophthalmic and Povidone Ophthalmic in people with Nasal and Pharyngeal Microbiome, run by Medical University of Vienna at 1 site in Austria.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 6 inclusion and 9 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 16 May 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Austria. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Nasal bacterial microbiome (time frame: change after 1 week treatment). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 16 May 2025.