Study of the genetic diversity of Moraxella spp. isolates obtained from corneal abscesses / Estudio de la diversidad genética de aislamientos de Moraxella spp. a partir de abscesos corneales

Abstract This is the first study of the genetic diversity of Moraxella spp. Isolates were detected in an Eye Hospital in the City of Buenos Aires. Due to the high frequency of Moraxella spp. observed in corneal abscesses, we decided to validate their identification at the species level, determine their drug susceptibility and perform molecular subtyping. Seventeen (17) isolates obtained from corneal abscesses were evaluated. The identification was carried out using a combination of biochemical tests and MALDI-TOF mass spectrometry. Of these isolates, 88.2% were identified as Moraxella lacunata, and 11.8% as Moraxella nonliquefaciens. Molecular subtyping was performed using the pulsed-field gel electrophoresis (PFGE) technique. All isolates were typable and thirteen digestion patterns were identified. Based on the obtained results, the PFGE technique using the SmaI enzyme can be used for epidemiological studies of strains of these species.

Resumen En este trabajo se presenta el primer estudio de diversidad genética de aislamientos de Moraxella spp. detectados en un hospital de oftalmología de la Ciudad Autónoma de Buenos Aires. Debido a la observación de una elevada frecuencia de Moraxella spp. en abscesos corneales, se decidió confirmar su identificación a nivel de especie, conocer su sensibilidad y realizar la subtipificación molecular. Se analizaron 17 aislamientos provenientes de abscesos corneales. La identificación se realizó mediante una combinación de pruebas bioquímicas y espectrometría de masas, MALDI-TOF MS. El 88,2% fueron identificados como Moraxella lacunata y el 11,8% como Moraxella nonliquefaciens. La subtipificación molecular se realizó por la técnica de electroforesis en gel de campo pulsado (PFGE). Todos los aislamientos fueron tipificables y se identificaron 13 patrones de digestión. Nuestros resultados muestran que la técnica de PFGE con la enzima SmaI es útil para hacer estudios epidemiológicos en cepas de estas especies.

Fulminant scleral abscess secondary to infected scleral buckle with Moraxella species

We here report a case of scleral buckle infection with fulminant scleral abscess secondary to Moraxella species. A 54-year-old chronic alcoholic male with a history of retinal detachment repair, with scleral buckle 8 years prior, presented with complaints of severe pain, redness, and swelling in the right eye since 2 weeks. The patient was diagnosed with scleral buckle infection, the buckle was removed, and cultures revealed Moraxella species. The postoperative course included fulminant scleral abscess treated with dual antibiotic therapy that included ceftriaxone and moxifloxacin. All systemic antibiotics were discontinued after 3 weeks, retina remained attached, and no recurrence occurred over a 1-year follow-up. Moraxella, though commonly associated with bacterial keratitis, can also lead to buckle infection, especially in chronic alcoholic and immunocompromised patients. In buckle infection, infected buckle along with sutures should be immediately removed without damaging underlying compromised sclera. Lastly, culture and drug sensitivity play a very important role in buckle infections.