Keratitis; Infectious Disease (Manifestation)NCT01925846
Pseudomonal Type Three Secretion System and Contact Lens Associated Microbial Keratitis
An observational study of Keratitis; Infectious Disease (Manifestation), run by National Taiwan University Hospital at 1 site in Taiwan.
Trial summary
Microbial infection of the cornea, also known as microbial keratitis, causes severe corneal inflammation that could result in permanent visual loss. Contact lens wear is the strongest risk factor related to microbial keratitis in developed countries. Read more about this study
- Who is it for?
- Ages 20 to 35 yearsHealthy volunteers can take part
- Conditions the study is for
- Keratitis; Infectious Disease (Manifestation)
- How many people
- 180 participants
- Where
- 1 siteTaiwan
- Study dates
- Jan 2013to Jul 2015
- Phase
- Observational
- 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 20 to 35 years
- All sexes
- Healthy volunteers accepted
- Adult
Study population: In order to understand the pathogenesis of CLMK, especially pseudomonal related CLMK, we proposed to recruit 180 volunteers who will wear different contact lens materials. We then collect the used contact lens and analyze 1) the microbiota on the used contact lens; 2) the bacterial-contact lens adhesion of wild strains, pscC mutant strains (T3SS needle-comples mutant), cytotoxic strain, and invasive strain P. aeruginosa; 3) the effect of shearing forces on bacterial-contact lens adhesion; 4) the bacteriocidal effect of multipurpose solution on different strains of P. aeruginosa.
Who may be able to join
- age 20-35 years old
- myopia less than -6.00D and astigmatism less than -1.50D
- previous soft contact lens wear discontinued for at least 2 weeks. -
Who cannot join
- subjects with previous RGP wear
- any ocular inflammation or infection, proved dry eye syndrome, glaucoma, ocular trauma or surgery, and topical medication instillation
- diabetic mellitus
- pregnancy
- status post corneal refractive surgery -
Trial locations and contacts
1 site in 1 country.
Taiwan1 site, 1 recruiting
- Recruiting
Department of Ophthlamology, National Taiwan University Hospital
Taipei, 10002
Fung-rong Hu, MD, +886-2-23123546 ext. 65819, fungronghu@ntu.edu.tw
Hsiao-sang Chu, MD, +886-928-980736, einahpets18@gmail.com
About this study
Official title: Association of Type Three Secretion System (T3SS) of Pseudomonas Aeruginosa With Pathogenesis of Contact Lens-Associated Microbial Keratitis (CLMK)
Microbial infection of the cornea, also known as microbial keratitis, causes severe corneal inflammation that could result in permanent visual loss. Contact lens wear is the strongest risk factor related to microbial keratitis in developed countries. The most commonly isolated pathogen of contact lens associated microbial keratitis (CLMK) is Pseudomonas aeruginosa, which accounts for over one third of the cases. Among the various virulence factors involved in the pathogenesis of pseudomonal keratitis, a secretion system known as type three secretion system (T3SS) secretes toxins that damage the host cells. ExoS is a bifunctional exotoxin with GTPase-activating protein (GAP) activity and ADP ribosyl transferase (ADPRT) activity. It results in an invasive phenotype of P. aeruginosa causing a relatively slower host cell death with intracellular invasion and possibly proliferation of bacterium. In contrast, ExoU expressing strains carries a cytotoxic phenotype that causes rapid host cell lysis due to its phospholipase activity. Previously, cytotoxic strains were reported to be more commonly found in patients with pseudomonal keratitis and were highly correlated with multidrug resistance.
In order to understand the pathogenesis of CLMK, especially pseudomonal related CLMK, we proposed to recruit 180 volunteers who will wear different contact lens materials. We then collect the used contact lens and analyze 1) the microbiota on the used contact lens; 2) the bacterial-contact lens adhesion of wild strains, pscC mutant strains (T3SS needle-comples mutant), cytotoxic strain, and invasive strain P. aeruginosa; 3) the effect of shearing forces on bacterial-contact lens adhesion; 4) the bacteriocidal effect of multipurpose solution on different strains of P. aeruginosa.
Read the detailed description
Subject recruitment
The inclusion criteria includes:
- age 20-35 years old
- myopia less than -6.00D and astigmatism less than -1.50D
- previous soft contact lens wear discontinued for at least 2 weeks.
Exclusion criteria includes:
- subjects with previous RGP wear
- any ocular inflammation or infection, proved dry eye syndrome, glaucoma, ocular trauma or surgery, and topical medication instillation
- diabetic mellitus
- pregnancy
- status post corneal refractive surgery
The aim and purpose of this study will be thoroughly explained to the potential participants. Informed consent will be obtained from all enrolled subjects. This study will be approved by our Institutional Review Board and adheres to the tenets of the Declaration of the Helsinki. A minimal of 12 subjects per group is required to show a difference in the microbiota for one classification level or more at a significance level of 0.05 and a power of 90%. Thus, the goal is to recruit 15 volunteers to wear each type of contact lens and 180 subjects totally for this study.
The recruitment will be divided into three stages. At the first stage, we will test 4 types of silicone hydrogel contact lenses, followed by testing 5 types of color-tinted hydrogel lenses at the second stage and 3 types of hydrogel lenses at the third stage. (T = types of lenses, which equals 4,5 and 3 at stage one, two and three).
At each stage, we will recruit subjects to certain amount (M) each time (M＝N×T , N equals 1,2,3…to 15). M subjects will then be randomized, equally distributed to wear T types of lenses by the random number method. Until the required case numberis achieved at the first stage, we will proceed to the second and the third stage with the same stratified randomization methods.( required case number, ΣM, equals 60, 75 and 45 at stage one, two and three).
Subjects are fitted with the soft contact lenses and are expected to wear the lenses for at least 6-8 hour per day. Standardized hand hygiene and lens care regimen are thoroughly explained to each subject to insert the contact lens. Each subject enrolled will be provided with the soft contact lenses without charge. After wear each day, the contact lenses must be returned and collected for material analysis.
- Keywords
- Pseudomonas aeruginosa, type three secretory system, contact lens associated microbial keratitis
- Medical subject headings
- Keratitis, Communicable Diseases, Pseudomonas Infections
What is being measured
The primary outcome is the main question the study is designed to answer.
bacterial adhesion assay
Measured: after co-culture for two hours
Secondary outcomes (1)
Identification of bacterial colonization to worn contact lenses
Measured: after the CL been worn for 6 hours
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted20 Aug 2013 (estimated)
- Study startJan 2013
- Primary completionJan 2015 (estimated)
- Study completionJul 2015 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Keratitis; Infectious Disease (Manifestation)Studies of the same condition, open and under way.
- More trials run by National Taiwan University HospitalThe 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
- Observational
- Observational model
- Cohort
- Time perspective
- Retrospective
- Enrolment
- 180 participants (estimated)
Sponsor and investigators
- Lead sponsor
- National Taiwan University Hospital
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
- Investigators
- HU FR Hu, professor, Study chair
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT01925846
- Sponsor's protocol ID
- 201212003RINC
- Status last verified
- Apr 2014
- First submitted
- 16 Aug 2013
- Last updated
- 15 Apr 2014
- Results posted
- No
- Data monitoring committee
- No
Study at a glance
From the registry record, last updated by the sponsor on 15 Apr 2014. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Association of Type Three Secretion System (T3SS) of Pseudomonas Aeruginosa With Pathogenesis of Contact Lens-Associated Microbial Keratitis (CLMK)
- ClinicalTrials.gov ID
- NCT01925846
- Acronym / sponsor ID
- 201212003RINC
- Keywords
- Pseudomonas aeruginosa, type three secretory system, contact lens associated microbial keratitis
- Study type
- Observational
- Recruitment status
- Unknown status
- Enrolment
- 180 participants (estimated)
- Lead sponsor
- National Taiwan University HospitalUniversity, hospital or other
- Study start
- Jan 2013
- Primary completion
- Jan 2015 (estimated)
- Study completion
- Jul 2015 (estimated)
- First posted
- 20 Aug 2013 (estimated)
- 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.
Microbial infection of the cornea, also known as microbial keratitis, causes severe corneal inflammation that could result in permanent visual loss. Contact lens wear is the strongest risk factor related to microbial keratitis in developed countries. The most commonly isolated pathogen of contact lens associated microbial keratitis (CLMK) is Pseudomonas aeruginosa, which accounts for over one third of the cases. Among the various virulence factors involved in the pathogenesis of pseudomonal keratitis, a secretion system known as type three secretion system (T3SS) secretes toxins that damage the host cells. ExoS is a bifunctional exotoxin with GTPase-activating protein (GAP) activity and ADP ribosyl transferase (ADPRT) activity. It results in an invasive phenotype of P. aeruginosa causing a relatively slower host cell death with intracellular invasion and possibly proliferation of bacterium. In contrast, ExoU expressing strains carries a cytotoxic phenotype that causes rapid host cell lysis due to its phospholipase activity. Previously, cytotoxic strains were reported to be more commonly found in patients with pseudomonal keratitis and were highly correlated with multidrug resistance.
In order to understand the pathogenesis of CLMK, especially pseudomonal related CLMK, we proposed to recruit 180 volunteers who will wear different contact lens materials. We then collect the used contact lens and analyze 1) the microbiota on the used contact lens; 2) the bacterial-contact lens adhesion of wild strains, pscC mutant strains (T3SS needle-comples mutant), cytotoxic strain, and invasive strain P. aeruginosa; 3) the effect of shearing forces on bacterial-contact lens adhesion; 4) the bacteriocidal effect of multipurpose solution on different strains of P. aeruginosa.
Detailed description
Subject recruitment
The inclusion criteria includes:
- age 20-35 years old
- myopia less than -6.00D and astigmatism less than -1.50D
- previous soft contact lens wear discontinued for at least 2 weeks.
Exclusion criteria includes:
- subjects with previous RGP wear
- any ocular inflammation or infection, proved dry eye syndrome, glaucoma, ocular trauma or surgery, and topical medication instillation
- diabetic mellitus
- pregnancy
- status post corneal refractive surgery
The aim and purpose of this study will be thoroughly explained to the potential participants. Informed consent will be obtained from all enrolled subjects. This study will be approved by our Institutional Review Board and adheres to the tenets of the Declaration of the Helsinki. A minimal of 12 subjects per group is required to show a difference in the microbiota for one classification level or more at a significance level of 0.05 and a power of 90%. Thus, the goal is to recruit 15 volunteers to wear each type of contact lens and 180 subjects totally for this study.
The recruitment will be divided into three stages. At the first stage, we will test 4 types of silicone hydrogel contact lenses, followed by testing 5 types of color-tinted hydrogel lenses at the second stage and 3 types of hydrogel lenses at the third stage. (T = types of lenses, which equals 4,5 and 3 at stage one, two and three).
At each stage, we will recruit subjects to certain amount (M) each time (M＝N×T , N equals 1,2,3…to 15). M subjects will then be randomized, equally distributed to wear T types of lenses by the random number method. Until the required case numberis achieved at the first stage, we will proceed to the second and the third stage with the same stratified randomization methods.( required case number, ΣM, equals 60, 75 and 45 at stage one, two and three).
Subjects are fitted with the soft contact lenses and are expected to wear the lenses for at least 6-8 hour per day. Standardized hand hygiene and lens care regimen are thoroughly explained to each subject to insert the contact lens. Each subject enrolled will be provided with the soft contact lenses without charge. After wear each day, the contact lenses must be returned and collected for material analysis.
Study design
- Observational model
- Cohort
- Time perspective
- Retrospective
Who may qualify
- Ages
- 20 to 35 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
- Study population
- In order to understand the pathogenesis of CLMK, especially pseudomonal related CLMK, we proposed to recruit 180 volunteers who will wear different contact lens materials. We then collect the used contact lens and analyze 1) the microbiota on the used contact lens; 2) the bacterial-contact lens adhesion of wild strains, pscC mutant strains (T3SS needle-comples mutant), cytotoxic strain, and invasive strain P. aeruginosa; 3) the effect of shearing forces on bacterial-contact lens adhesion; 4) the bacteriocidal effect of multipurpose solution on different strains of P. aeruginosa.
Key inclusion criteria (3 listed)
- age 20-35 years old
- myopia less than -6.00D and astigmatism less than -1.50D
- previous soft contact lens wear discontinued for at least 2 weeks. -
Key exclusion criteria (5 listed)
- subjects with previous RGP wear
- any ocular inflammation or infection, proved dry eye syndrome, glaucoma, ocular trauma or surgery, and topical medication instillation
- diabetic mellitus
- pregnancy
- status post corneal refractive surgery -
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Primary outcome
bacterial adhesion assay
Time frame: after co-culture for two hours
1 secondary outcome
Identification of bacterial colonization to worn contact lenses
Time frame: after the CL been worn for 6 hours
Results and safety
Results are not available in the source record.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 15 Apr 2014.
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.
HU FR Hu, professor study chair
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Keratitis; Infectious Disease (Manifestation), run by National Taiwan University Hospital at 1 site in Taiwan.
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 3 inclusion and 5 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: status not confirmed, as of the sponsor's last update on 15 Apr 2014. 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 Taiwan. 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.
Are results available for this study?
Results are not available in the source record.
How can a doctor refer a patient or contact the research team?
Contact Fung-rong Hu, Professor (02-23123456 ext. 65189, fungronghu@ntu.edu.tw), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
bacterial adhesion assay (time frame: after co-culture for two hours). 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 15 Apr 2014.