title: Impression membrane for the diagnosis of microbial keratitis.
abstract: OBJECTIVE
  To evaluate a corneal impression membrane (CIM) for isolation of bacteria, fungi and acanthamoeba in suspected microbial keratitis.
  
  
  METHODS
  Consecutive patients presenting with suspected microbial keratitis were included. For each patient, samples were collected in a random order using a surgical blade and a 4-mm-diameter polytetrafluoroethylene CIM disc, and transported in brain heart infusion broth. Risk factors, best corrected visual acuity (BCVA), size, location, depth and healing time of the ulcer were recorded. The microbial isolation rate was used to compare sampling methods.
  
  
  RESULTS
  130 patients were included (mean age 62.6 years, SD 19.0). An antimicrobial had been used prior to presentation in 36 (27.7%) patients. Mean major and minor ulcer diameters were 2.1 mm (SD 2.0) and 1.6 mm (SD 1.7). Mean healing time was 12.4 days (SD 13.6). BCVA at presentation and following healing was 0.7 (SD 0.7) and 0.62 (SD 0.7) (p=0.34). There were 66 isolates (50.8%); 53 (40.8%) using a CIM and 35 (26.9%) using a blade (p=0.02). ITALIC! Staphylococcus aureus and coagulase-negative staphylococci were the commonest isolates. Isolation rate was not influenced by organism type, although in four cases ITALIC! Acanthamoeba spp. were isolated; three using CIM and one a blade.
  
  
  CONCLUSIONS
  In this study, the isolation of microorganisms from cases of suspected microbial keratitis was significantly higher using a CIM than a surgical blade. A CIM may be a useful alternative or addition for sample collection in microbial keratitis.
authors.affiliation: St Pauls Eye Unit, Royal Liverpool University Hospital, Liverpool, UK Department of Eye and Vision Science, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, UK.
authors.forename: Stephen
authors.initials: S
authors.lastname: Kaye
authors.affiliation: St Pauls Eye Unit, Royal Liverpool University Hospital, Liverpool, UK Department of Eye and Vision Science, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, UK.
authors.forename: Henri
authors.initials: H
authors.lastname: Sueke
authors.affiliation: St Pauls Eye Unit, Royal Liverpool University Hospital, Liverpool, UK.
authors.forename: Vito
authors.initials: V
authors.lastname: Romano
authors.affiliation: St Pauls Eye Unit, Royal Liverpool University Hospital, Liverpool, UK.
authors.forename: Jern Yee
authors.initials: JY
authors.lastname: Chen
authors.affiliation: Corneal Service, Moorfields Eye Hospital, London, UK.
authors.forename: Nicole
authors.initials: N
authors.lastname: Carnt
authors.affiliation: Corneal Service, Moorfields Eye Hospital, London, UK.
authors.forename: Stephen
authors.initials: S
authors.lastname: Tuft
authors.affiliation: Department of Medical Microbiology, Royal Liverpool University Hospital, Liverpool, UK.
authors.forename: Timothy
authors.initials: T
authors.lastname: Neal
mesh_terms: D015823:Acanthamoeba Keratitis / Q000175:diagnosis* / Q000188:drug therapy / Q000469:parasitology; D000328:Adult; D000368:Aged; D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D003320:Corneal Ulcer / Q000175:diagnosis* / Q000188:drug therapy / Q000382:microbiology / Q000469:parasitology; D003584:Cytological Techniques; D015818:Eye Infections, Bacterial / Q000175:diagnosis* / Q000188:drug therapy / Q000382:microbiology; D015821:Eye Infections, Fungal / Q000175:diagnosis* / Q000188:drug therapy / Q000382:microbiology; D015822:Eye Infections, Parasitic / Q000175:diagnosis* / Q000188:drug therapy / Q000469:parasitology; D005260:Female; D024841:Fluoroquinolones / Q000627:therapeutic use; D006801:Humans; D008297:Male; D008567:Membranes, Artificial; D008828:Microbiological Techniques; D008875:Middle Aged; D011138:Polytetrafluoroethylene; D014792:Visual Acuity
chemical_list: D000900:Anti-Bacterial Agents; D024841:Fluoroquinolones; D008567:Membranes, Artificial; D011138:Polytetrafluoroethylene
keywords: Cornea; Diagnostic tests/Investigation; Infection; Microbiology