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An outbreak of keratitis caused by Mycobacterium immunogenum

Jorge Luiz Mello Sampaio1, Doraldo Nassar Junior, Denise de Freitas

  • 1Departamento de Microbiologia, Imunologia e Parasitologia, Universidade Federal de São Paulo--Escola Paulista de Medicina, Rua Botucatu, 862--3 degrees andar, 04023-062 São Paulo, Brazil. sampaio@ecb.epm.br

Journal of Clinical Microbiology
|September 7, 2006
PubMed

Insights

An outbreak of infectious keratitis occurred in Brazil following myopia surgery. A novel variant of Mycobacterium immunogenum was identified as the cause, highlighting a rare pathogen in post-surgical eye infections.

Area of Science:

  • Ophthalmology
  • Microbiology
  • Infectious Diseases

Background:

  • Myopia surgical correction is a common procedure.
  • Infectious keratitis is a serious complication that can lead to vision loss.
  • Mycobacterium species are known, though less common, causes of keratitis.

Purpose of the Study:

  • To identify the causative agent of an infectious keratitis outbreak following myopia surgery.
  • To characterize the isolated Mycobacterium species.
  • To determine the genetic relatedness of the isolates.

Main Methods:

  • Polymerase chain reaction restriction enzyme analysis (PCR-REA) of hsp65 and 16S-23S rRNA internal transcribed spacer (ITS) regions.
  • Phenotypic testing and partial gene sequencing (hsp65, sodA, rpoB, 16S rRNA).
  • Pulsed-field gel electrophoresis (PFGE) and enterobacterial repetitive intergenic consensus-PCR (ERIC-PCR) for clonal analysis.

Main Results:

  • Five patients developed infectious keratitis after myopia surgery.
  • A variant of Mycobacterium immunogenum was isolated from four patients.
  • Molecular typing confirmed a single clone responsible for the outbreak.
  • The source of infection remained undetermined.

Conclusions:

  • This is the first reported outbreak of infectious keratitis caused by this variant of Mycobacterium immunogenum.
  • The findings underscore the importance of identifying unusual pathogens in post-surgical infections.
  • Further investigation is needed to identify the source of this specific outbreak.

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