Corynebacterium propinquum Keratitis Identified Using MALDI-TOF

Area of Science:

• Ophthalmology
• Medical Microbiology
• Infectious Diseases

Background:

• Ocular infections require accurate and rapid microbial identification for effective treatment.
• Distinguishing between similar bacterial species is crucial for diagnosing and managing infectious keratitis.
• The matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry method offers a rapid and cost-effective approach to bacterial identification.

Observation:

• A 94-year-old female patient presented with suppurative keratitis, a severe corneal infection.
• Her medical history included Fuchs corneal dystrophy, corneal transplantation, and glaucoma, complicating the clinical picture.
• Gram staining revealed coryneform bacteria, prompting further identification.

Findings:

• MALDI-TOF successfully identified the causative agent as Corynebacterium propinquum.
• This identification was further confirmed using RNA polymerase beta subunit (rpoB) gene sequencing.
• The patient's vision improved after treatment with topical antibiotics (cefazolin, gentamicin) and fluorometholone.

Implications:

• MALDI-TOF is a valuable tool for identifying uncommon and difficult-to-distinguish bacterial isolates in clinical microbiology.
• The method's efficiency and low cost can significantly improve the laboratory diagnosis of ocular infections.
• Accurate identification of pathogens like C. propinquum is essential for guiding appropriate therapeutic interventions in ophthalmology.