title: Risk factors for microbial bioburden during daily wear of silicone hydrogel contact lenses.
abstract: OBJECTIVE
  To assess risk factors associated with substantial microbial bioburden of lids, conjunctivae, contact lenses, and storage cases during daily wear of silicone hydrogel contact lenses.
  
  
  METHODS
  Two hundred eighteen patients were fit to lotrafilcon A lenses, randomized to use either a multipurpose solution or a hydrogen peroxide care system, and followed up for 1 year. Lenses, lens transport saline, lids, conjunctivae, and storage cases were cultured and considered to have substantial microbial bioburden when they harbored high levels of commensal or pathogenic organisms. Univariate and multivariate logistic regression analyses were conducted to examine which demographic covariates were associated with significant bioburden at each location while controlling for solution use.
  
  
  RESULTS
  In multivariate analyses, smoking trended toward an association with lens bioburden (odds ratio [OR]=2.15, 95% confidence interval [CI]: 0.95-4.88). Clerical occupations were found to be associated with more frequent overall storage case contamination (OR=3.51, 95% CI: 1.15-10.70) and, specifically, higher gram-positive storage case contamination (OR=5.57, 95% CI: 1.82-17.06). The peroxide system was associated with more frequent storage case contamination (OR=7.6, 95% CI: 3.79-15.19). Coagulase-negative staphylococci (CNS) were the most frequently cultured organisms within storage cases, and in multivariate analyses, CNS were more frequently found in storage cases of peroxide users (OR=6.12, 95% CI: 2.91-13.09).
  
  
  CONCLUSIONS
  Clerical occupations were associated with increased microbial bioburden of storage cases during daily wear of silicone hydrogel lenses. Smoking may increase the risk of lens contamination. Storage cases are most frequently contaminated with normal skin flora, and peroxide cases were associated with more frequent contamination. However, the solution type was not associated with lid or lens contamination nor with corneal infiltrative events in this study.
authors.affiliation: Departments of Epidemiology & Biostatistics (Y.J., S.M.D.), Pathology (M.J., S.B., A.N.F.), Division of Information Technology Services (R.B., M.G.), Case Western Reserve University, Cleveland, OH; Department of Ophthalmology & Visual Sciences (S.R., L.B.S.-F.) and University Hospitals Eye Institute, University Hospitals Case Medical Center, Cleveland, OH; and Alcon Research Ltd. (J.K.), Fort Worth, TX.
authors.forename: Ying
authors.initials: Y
authors.lastname: Jiang
authors.forename: Michael
authors.initials: M
authors.lastname: Jacobs
authors.forename: Saralee
authors.initials: S
authors.lastname: Bajaksouzian
authors.forename: Altreisha N
authors.initials: AN
authors.lastname: Foster
authors.forename: Sara M
authors.initials: SM
authors.lastname: Debanne
authors.forename: Roger
authors.initials: R
authors.lastname: Bielefeld
authors.forename: Matt
authors.initials: M
authors.lastname: Garvey
authors.forename: Sangeetha
authors.initials: S
authors.lastname: Raghupathy
authors.forename: Jami
authors.initials: J
authors.lastname: Kern
authors.forename: Loretta B
authors.initials: LB
authors.lastname: Szczotka-Flynn
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000890:Anti-Infective Agents / Q000494:pharmacology; D003228:Conjunctiva / Q000382:microbiology; D018639:Contact Lens Solutions / Q000494:pharmacology; D003263:Contact Lenses, Hydrophilic / Q000382:microbiology*; D004866:Equipment Contamination / Q000706:statistics & numerical data; D015818:Eye Infections, Bacterial / Q000517:prevention & control; D005143:Eyelids / Q000382:microbiology; D005260:Female; D006801:Humans; D020100:Hydrogels; D006861:Hydrogen Peroxide / Q000494:pharmacology; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D009790:Occupations / Q000706:statistics & numerical data; D012307:Risk Factors; D020034:Silicone Gels; D012907:Smoking / Q000009:adverse effects; D055815:Young Adult
chemical_list: D000890:Anti-Infective Agents; D018639:Contact Lens Solutions; D020100:Hydrogels; D020034:Silicone Gels; D006861:Hydrogen Peroxide