Moraxella Keratitis: Analysis Of Risk Factors, Clinical Characteristics, Management, Treatment Outcomes And Bacteriological Profile (2010-2019)

The aim of this study is to analyze the risk factors, clinical characteristics, management, treatment outcomes and bacteriological profile of culture-proven cases of Moraxella sp. keratitis from a large tertiary Corneal Unit in Spain between 2010 and 2019.

Apart from phenotypic testing, Matrix assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) and molecular techniques such as DNA sequencing are used in order to subtype the different species of Moraxella sp.  

Various centers worldwide have identified changing trends of infective keratitis. Moraxella sp. is an uncommon pathogen often associated with impaired host immunity, accounting for approximately 2% to 3% of all bacterial corneal ulcers. Moraxella sp. keratitis appears to be on the rise on recent reports. Advances in technology (automated systems and test kits) now allow identifying ocular isolates of Moraxella to genus. 

Fifty-eight culture-proven cases of Moraxella sp. keratitis (58 eyes) diagnosed and treated between January 2010 and December 2019 at a tertiary hospital in Spain, were identified and retrospectively reviewed for ocular and systemic risk factors, treatment modalities, and outcomes, as well as for Moraxella genus identification, antimicrobial sensitivity and resistance data. Both, the clinical and microbiological records of these patients, were retrospectively reviewed.

58 subjects had culture-proven Moraxella sp. keratitis. The average age was 63.44, with age ranging from 3 to 93 years. Twenty one patients (36.2%) had an associated ocular risk factor. In relation with systemic conditions, seven patients (12%) were hepatitis C virus (HCV) +, six patients (10.3%) were HIV +, two (3%) had alcoholic cirrhosis.

We identified Moraxella sp isolates from keratitis using MALDI-TOF MS and genetic techniques. 37 isolates were identified as M. lacunata (63.8%), 11 isolates were M. non liquefaciens (18.9%), only three cases of M. catarrhalis (5%). All patients HCV+ and HIV+ presented M. lacunata, except one (M. non liquefaciens).

Resistance to fluoroquinolones, gentamicin and cephalosporin was not seen.

In conclusion, Moraxella sp. keratitis, though uncommon (2-3%), has been recognized as a cause of bacterial keratitis. Because of its rarity, a paucity of information exists on Moraxella keratitis within the current published literatura. Large cohorts of Moraxella keratitis are difficult to obtain, and to the best of our knowledge, only 3 studies are available reporting on 50 or more patients. And only one of them includes the identification of Moraxella species using DNA sequencing and MALDI-TOF MS methods.