Moraxella Nonliquefaciens Keratitis: Report Of 3 Clinical Cases With Different Outcomes

To report a series of 3 cases of keratitis with positive microbiological culture for Moraxella nonliquefaciens and its torpid evolution despite intensive treatment with topical and oral antibiotics.

The species of the genus Moraxella occur as gram-negative coccobacilli. They are part of the usual flora of the upper respiratory tract and are considered to be of low pathogenic power. At the ocular level, Moraxella nonliquefaciens mainly produces cases of endophthalmitis, although 6 cases of corneal involvement by this pathogen have been recently published.

All patients had predisposing risk factors both ocular (glaucoma, previous ocular surgeries) and systemic (diabetes mellitus, hypothyrodism, stroke).

All patients belong to the health area of Ferrol (northeastern region of Spain), and were followed up by the cornea section of the Ophthalmology Department of the University Hospital of Ferrol.

This is a 75-year-old male patient and two women aged 70 and 85 years respectively, who presented at diagnosis with red eye, pain and corneal infiltrate.

The 3 cases appeared between November and December 2021.

The best previous corrected visual acuity was no light perception for women and 0.10 for man.

On the first day, a corneal scraping was performed for Gram staining and culture in different media (Saboureaud agar, chocolate agar and Thioglycollate) and intensive topical treatment was started empirically with Ceftacidime and Vancomycin. In 1 case, treatment with oral moxifloxacin was also started at the outset.

Check-ups were performed at 48 hours and 7 days, modifying the treatment according to the results of the microbiological culture and antibiogram:

All were positive for Moraxella nonliquefaciens, but one of the patients also had a co-infection with Staphylococcus Epidermidis.

In 2 patients the antibiogram indicated resistance to Vancomycin, so the treatment regimen was changed to topical Ceftacidime and Moxifloxacin and oral amoxicillin-clavulanic acid.

Oral prednisone 30 mg per day was added in all cases.

Despite treatment, 1 of the 3 patients had poor evolution of the corneal ulcers, for which evisceration was considered. The other 2 patients have resolved the active infection remaining with visions very similar to previous ones.

Ocular infections due to Moraxella nonliquefaciens have been rarely described, being endophthalmitis the most frequent ocular manifestation and keratitis one of the rarest with only six reported cases described recently.

Keratitis caused by Moraxella nonliquefaciens is rare and should be suspected in patients with local predisposing factors such as corneal damage or previous corneal infection.

We present 3 cases that occurred in our hospital in a period of 2 months with no relationship between these patients. We even wondered whether this increase in cases could be due to the use of surgical masks in the context of the SARS-Cov-2 pandemic and secondary ocular contamination.