Risk factors and causative organisms in microbial keratitis in daily disposable contact lens wear

<div><p>Purpose</p><p>This study investigated independent risk factors and causative organisms in microbial keratitis in daily disposable contact lens (CL)-wearers.</p><p>Methods</p><p>A multisite prospective case-control study was undertaken. Cases were daily disposable CL-wearers attending Moorfields Eye Hospital with microbial keratitis and those reported through a one-year surveillance study in Australia and in New Zealand. A population-based telephone survey identified daily disposable CL-wearing controls. Subjects completed a questionnaire describing CL-wear history, hygiene and demographics. The sample used for risk factor analysis was weighted in proportion to the CL-wearing population at each location. Corneal scrape results were accessed. Independent risk factors were determined using multiple binary logistic regression. Causative organisms in different CL-wear modalities were compared using a chi-squared test.</p><p>Results</p><p>963 daily disposable CL-wearers were identified, from which 67 cases and 374 controls were sampled. Independent risk factors were; wearing CLs every day compared with less frequent use (OR 10.4x; 95% CI 2.9–56.4), any overnight wear (OR 1.8x; 95% CI 1.6–2.1), less frequent hand washing (OR 1.8x; 95% CI 1.6–2.0), and smoking (OR 1.3x; 95% CI 1.1–1.6). Certain daily disposable CLs (OR 0.2x; 95% CI 0.1–0.2) had protective effects. Environmental organisms were less frequently recovered with daily disposable CLs (20%), compared with other modalities (36%; p<0.02).</p><p>Conclusion</p><p>Overnight wear, increased exposure in daily wear, smoking and poor hand hygiene are significant risk factors for microbial keratitis with daily disposable CLs. Risk varied with daily disposable CL type. The profile of causative organisms is consistent with less severe disease.</p></div

Independent risk factors for all and moderate/severe microbial keratitis identified by multiple logistic regression analysis.

<p>Independent risk factors for all and moderate/severe microbial keratitis identified by multiple logistic regression analysis.</p

Corneal scrape results for daily disposable wearers and wearers of other soft and silicone hydrogel lenses from three geographic sites.

<p>Corneal scrape results for daily disposable wearers and wearers of other soft and silicone hydrogel lenses from three geographic sites.</p

Microbial keratitis cases and controls using daily disposable contact lenses by location.

<p>Microbial keratitis cases and controls using daily disposable contact lenses by location.</p

Additional file 1 of Assessment of genotypes, endosymbionts and clinical characteristics of Acanthamoeba recovered from ocular infection

Additional file 1: Table S1: Reference Acanthamoeba strains used in this study for phylogenetic analysis. Table 2: Genotype and species identification of Acanthamoeba isolates recovered from AK patients. Map 1: Map showing the states of the AK patients from different states of India with sample codes and identified genotypes of Acanthamoeba from AK patients. The map was created using ArcGIS (Esri GIS, California, USA). Fig. S1. Monthly distribution of AK cases during study period. Fig. S2. Sequence alignment of Acanthamoeba 18S rDNA DF3 region using ClustalW. Table S3. Overall clinical presentation of the keratitis patients infected with Acanthamoeba spp. Fig S3. Phylogenetic tree inferred from the 18S (ITS1) rDNA sequence of fungi; tree was created using the neighbour-joining approach with the Kimura 2-parameter based on 1000 replicates bootstrap values. Fig. S4. Agarose (1%) gel image of PCR amplicons of 13 Acanthamoeba isolates (18S rRNA), PCR assay was performed using Acanthamoeba genus specific primer pair JDPFw and JDPRv which yielded ~450bp amplicons. Fig. S5: Agarose (1%) gel image of PCR amplicons of 13 Acanthamoeba isolates targeting intracellular bacteria 16S rRNA, primer pair 515Fw and 806Rv (V4, 16S rRNA) was used which yielded ~293bp amplicons

X-linked Megalocornea Families A–J.

<p>(A) Pedigree of Families A–G. Black shaded squares denote clinically and genetically confirmed affected males; grey shaded squares denote clinically diagnosed affected males but DNA samples were not available for testing; dotted circles denote genetically confirmed carrier females; ? = presumed carrier females but DNA samples were not available for testing; clear squares and circles denote unaffected individuals. Arrowhead indicates proband in each family. Control sequence electropherogram is shown above patient sequence. (B) Pedigree of Family H and sequence electropherogram showing a 9,033 bp deletion encompassing <i>CHRDL1</i> exon 5 and 8 bp insertion. (C) Pedigree of Families I and J. Deletion of the entire <i>CHRDL1</i> gene (exon 1 to exon 12) in the proband is shown in agarose gel images. The flanking genes, <i>RGAG1</i> and <i>PAK3</i> are present. NTC, non-template control (D) Schematic representation of presence or absence of the <i>CHRDL1</i> gene and flanking genes <i>RGAG1</i> and <i>PAK3</i> (Ensembl nomenclature hg19 genome build) in Families I and J.</p

Summary of <i>CHRDL1</i> mutations.

<p>(A) Schematic of CHRDL1 protein domains. The following abbreviations are used: SP, signal peptide; VWFC, von Willebrand factor, type C domain. (B) Schematic of the <i>CHRDL1</i> gene. (C) <i>CHRDL1</i> mutations previously reported in X-linked megalocornea families <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0104163#pone.0104163-Webb1" target="_blank">[3]</a>, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0104163#pone.0104163-Han1" target="_blank">[6]</a>. Frameshift, splicing, nonsense, missense, and whole gene deletion mutations were identified. (D) Novel <i>CHRDL1</i> mutations identified in MGC1 families in this study (Families A–J). The dagger (†) indicates Family K with MMR syndrome.</p

Ocular phenotype: X-linked megalocornea patients.

<p>The following abbreviations and symbols have been used: NA = not available; HWTW = cornea horizontal diameter (white to white); IOP = intraocular pressure.</p

Novel <i>CHRDL1</i> missense mutation in a patient diagnosed with MMR.

<p>(A) Pedigree of Family K with megalocornea-mental retardation (MMR) syndrome. Squares, males; circles, females; diamonds, unknown gender; shaded, affected; dotted, carrier; clear, unaffected. Arrowhead indicates proband. Sequence electropherograms show the <i>CHRDL1</i> missense mutation c.464G>A; p.(Cys155Tyr), which segregates in Family K. (B–C) The proband at ages 3, and 6 years, respectively, presented with bilateral megalocorneae, broad forehead, bilateral epicanthic folds, a tented upper lip, and downturned corners of the mouth. (D–E) Frontal and sides of the proband at age of 10 years.</p