title: Confocal microscopy for Nocardia keratitis.
abstract: OBJECTIVE
  To assess the role of confocal microscopy for in vivo detection of Nocardia in patients with microbial keratitis.
  
  
  METHODS
  Retrospective interventional case series.
  
  
  METHODS
  Three patients with microbiologically proven Nocardia keratitis.
  
  
  METHODS
  Confocal microscopy.
  
  
  METHODS
  We performed confocal microscopy in microbiologically proven cases of Nocardia asteroides keratitis. A masked observer examined the images. For better understanding of the images, we also performed confocal microscopy on a blood agar culture plate with Nocardia growth.
  
  
  RESULTS
  Confocal microscopy of infiltrated cornea revealed highly reflective, short, thin branching filaments with bright inflammatory cells in the background. The filaments were seen clearly at the edge of the infiltrate. In scans with faint images, these filaments became more visible on inversion of bright and dark components. Confocal microscopy of cultured organisms also revealed filamentous beaded structures with a morphology identical to that of those seen in vivo.
  
  
  CONCLUSIONS
  Nocardia, a filamentous bacterium, produces a distinct image on confocal microscopy. This in vivo examination technique may be useful in cases of deep-seated infiltrates where routine microbiology workup does not yield positive results.
authors.affiliation: Cornea & Anterior Segment Service, L. V. Prasad Eye Institute, Banjara Hills, Hyderabad, India.
authors.forename: Pravin K
authors.initials: PK
authors.lastname: Vaddavalli
authors.forename: Prashant
authors.initials: P
authors.lastname: Garg
authors.forename: Savitri
authors.initials: S
authors.lastname: Sharma
authors.forename: Ravi
authors.initials: R
authors.lastname: Thomas
authors.forename: Gullapalli N
authors.initials: GN
authors.lastname: Rao
mesh_terms: D000328:Adult; D000583:Amikacin / Q000627:therapeutic use; D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D003131:Combined Modality Therapy; D015818:Eye Infections, Bacterial / Q000175:diagnosis* / Q000382:microbiology / Q000628:therapy; D005260:Female; D006801:Humans; D007634:Keratitis / Q000175:diagnosis* / Q000382:microbiology / Q000628:therapy; D015948:Keratoplasty, Penetrating; D008297:Male; D018613:Microscopy, Confocal / Q000379:methods*; D008875:Middle Aged; D009617:Nocardia Infections / Q000175:diagnosis* / Q000382:microbiology / Q000628:therapy; D009616:Nocardia asteroides / Q000166:cytology* / Q000302:isolation & purification; D012189:Retrospective Studies
chemical_list: D000900:Anti-Bacterial Agents; D000583:Amikacin