Background/aims To describe the risk factors, clinical features, bacterial subspecies characteristics and treatment outcomes of Moraxella keratitis in a single centre.
Methods A retrospective review of all patients diagnosed with Moraxella keratitis between November 2012 and December 2017 at the Royal Victoria Eye and Ear Hospital, Dublin, Ireland was performed. Matrix-assisted laser desorption ionisation time-of-flight (MALDI-TOF) mass spectrometry was used to identify Moraxella subspecies.
Results Forty-one cases of Moraxella keratitis were identified. Previous ocular surgery and diabetes were the most common local and systemic risk factors. The most common appearance on presentation was an oval-shaped paracentral infiltrate with a mean diameter of 4.2 mm. Mean presenting and final logarithm of minimal angle of resolution visual acuity were 1.307±0.74 and 0.99±1.01, respectively. Surgical procedures, including penetrating keratoplasty, corneal glueing or evisceration, were required to manage nine (22%) patients. Mean time to complete corneal epithelialisation was 32 (range, 7–109) days and mean duration of topical antibiotic therapy was 54 (range, 9–124) days. MALDI-TOF analysis revealed the following Moraxella subspecies: nonliquifaciens (16; 39%), lacunata (15; 36%), osloensis (4; 10%) and catarrhalis (2; 5%). In four cases (10%), subspecies analysis was inconclusive. M. nonliquifaciens and M. lacunata were associated with larger infiltrates on presentation (p<0.05), required more surgical intervention and longer treatment duration (p<0.001).
Conclusion In this large series of patients from Ireland, Moraxella keratitis was notable for its severity on presentation, slow response to antimicrobial therapy, high risk of surgical intervention and poor visual outcome. We have demonstrated the value of subspecies identification using MALDI-TOF by reporting significant differences in the clinical features and prognosis of M. nonliquifaciens and M. lacunata compared with other subspecies.
- ocular surface
- treatment medical
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Contributors CCM, SJK and TJM conceived of the presented idea. TJM developed the theory, collected the data and performed the analysis. SJK provided key microbiological data and results. CCM verified the analytical methods. CCM encouraged TJM to investigate subspecies analysis and supervised the findings of the work. All authors discussed the results and contributed to the final manuscript.
Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
Competing interests None declared.
Patient consent for publication Not required.
Ethics approval Approval for this study was granted by the Royal Victoria Eye and Ear Hospital Clinical Audit Committee.
Provenance and peer review Not commissioned; externally peer reviewed.
Data sharing statement Data are available upon reasonable request. Deidentified patient data are available from the authors of the study (TJM email: firstname.lastname@example.org) when used for further research in the area.