Infectious crystalline keratopathy. Role of nutritionally variant streptococci and other bacterial factors

Ophthalmology. 1991 Feb;98(2):159-69. doi: 10.1016/s0161-6420(91)32321-2.


Infectious crystalline keratopathy (ICK) is a chronic corneal infection characterized by interlamellar plaques of gram-positive coccal bacteria in the absence of inflammatory cells. It generally occurs within a corneal graft. Viridans streptococci are usually isolated, but the clinical response to antibiotics is poor and disparate with the in vitro antimicrobial sensitivities. These features suggest the possibility of unusual bacterial factors in pathogenesis. Four cases caused by nutritionally variant viridans streptococci are described. The organisms were fully characterized. They have a rare nutritional requirement for pyridoxal and require defined culture conditions and specific identification. Nutritional variant streptococci (NVS) are principally described as causing endocarditis, another infection involving an avascular collagenous tissue, and exhibiting similar biologic behavior. Electronmicrographic evidence is also adduced that suggests the possible importance of intracorneal glycocalyx deposition. Such factors might explain the anomalous clinical characteristics of this condition.

Publication types

  • Case Reports
  • Review

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Anti-Bacterial Agents / therapeutic use
  • Bacterial Outer Membrane Proteins / metabolism
  • Corneal Diseases / drug therapy
  • Corneal Diseases / microbiology*
  • Corneal Diseases / pathology
  • Eye Infections, Bacterial / drug therapy
  • Eye Infections, Bacterial / microbiology*
  • Eye Infections, Bacterial / pathology
  • Female
  • Humans
  • Keratoplasty, Penetrating
  • Pyridoxal / metabolism
  • Streptococcal Infections / drug therapy
  • Streptococcal Infections / microbiology*
  • Streptococcal Infections / pathology
  • Streptococcus / isolation & purification
  • Streptococcus / metabolism
  • Streptococcus / physiology*


  • Anti-Bacterial Agents
  • Bacterial Outer Membrane Proteins
  • Pyridoxal