Pseudomonal Type Three Secretion System and Contact Lens Associated Microbial Keratitis

NCT01925846 | Unknown

• 1 other identifier: 201212003RINC
• Study Type: observational
• Target: 180
• Locations: 1 country
• Sites: 1

Brief 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. 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.

Conditions

Keratitis; Infectious Disease (Manifestation)

Keywords

Pseudomonas aeruginosa; type three secretory system; contact lens associated microbial keratitis

Outcome Measures

Primary Outcomes (1)

• bacterial adhesion assay

  after co-culture for two hours

Secondary Outcomes (1)

• Identification of bacterial colonization to worn contact lenses

  after the CL been worn for 6 hours

Eligibility Criteria

• Age: 20 Years - 35 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)
• Sampling Method: Probability Sample

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.

You may qualify if:

• 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. -

You may not qualify if:

• 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 -

Sponsors & Collaborators

• National Taiwan University Hospital: lead

Study Sites (1)

Department of Ophthlamology, National Taiwan University Hospital

Taipei, 10002, Taiwan

RECRUITING

MeSH Terms

Conditions

Keratitis; Communicable Diseases; Pseudomonas Infections

Condition Hierarchy (Ancestors)

Corneal Diseases; Eye Diseases; Infections; Disease Attributes; Pathologic Processes; Pathological Conditions, Signs and Symptoms; Gram-Negative Bacterial Infections; Bacterial Infections; Bacterial Infections and Mycoses

Study Officials

• HU FR Hu, professor

  STUDY CHAIR

Central Study Contacts

Fung-rong Hu, Professor

CONTACT

02-23123456; fungronghu@ntu.edu.tw

Hsiao-sang Chu, Professor

CONTACT

+886-928-980736; einahpets18@gmail.com

Study Design

• Study Type: observational
• Observational Model: COHORT
• Time Perspective: RETROSPECTIVE
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: August 16, 2013
• First Posted: August 20, 2013
• Study Start: January 1, 2013
• Primary Completion: January 1, 2015
• Study Completion: July 1, 2015
• Last Updated: April 15, 2014

Record last verified: 2014-04

Locations

TW (1)