Alcaligenes xylosoxidans Contact Lens–Related Keratitis—A Case Report and Literature Review

Atypical microbial keratitis

Atypical microbial keratitis refers to corneal infections caused by micro-organisms not commonly encountered in clinical practice. Unlike infections caused by common bacteria, cases of atypical microbial keratitis are often associated with worse clinical outcomes and visual prognosis. This is due to the challenges in the identification of causative organisms with standard diagnostic techniques, resulting in delays in the initiation of appropriate therapies. Furthermore, due to the comparatively lower incidence of atypical microbial keratitis, there is limited literature on effective management strategies for some of these difficult to manage corneal infections. This review highlights the current management and available evidence of atypical microbial keratitis, focusing on atypical mycobacteria keratitis, nocardia keratitis, achromobacter keratitis, and pythium keratitis. It will also describe the management of two uncommonly encountered conditions, infectious crystalline keratopathy and post-refractive infectious keratitis. This review can be used as a guide for clinicians managing patients with such challenging corneal infections.

Microbiological Evaluation of Bandage Soft Contact Lenses Used in Management of Persistent Corneal Epithelial Defects

PURPOSE

To investigate the rate and agents of contamination in bandage soft contact lenses fitted for management of persistent corneal epithelial defects.

METHODS

This prospective comparative case series enrolled 57 consecutive eyes fitted with bandage contact lenses for treatment of persistent corneal epithelial defects. The lenses were collected at the time of epithelial closure or when it was necessary to exchange contact lenses and were immediately placed in sterile tubes containing an enriched thioglycolate liquid medium. When contamination of the contact lens was detected, the microorganism was cultured in different media and identified based on various tests. All isolates were tested for susceptibility to various antibiotics. Univariate analyses were used to evaluate the influence of different variables (duration of contact lens use, use of topical corticosteroids, presence of blepharitis, contact lens deposits, and presence of sutures) on bandage contact lens contamination.

RESULTS

Seventeen of the contact lenses (29.8%) were contaminated. The most commonly isolated pathogen was Staphylococcus epidermidis (n = 10), followed by Enterobacter cloacae (n = 3), Staphylococcus aureus (n = 1), Streptococcus viridans (n = 1), and Alcaligenes spp. (n = 1). One contact lens yielded a mixed infection with E. cloacae and Candida spp. Infectious keratitis was not observed in any eyes. Correlations between contact lens contamination and patient- and lens-related variables were not statistically significant.

CONCLUSIONS

Most bandage contact lenses (70.2%) used for treatment of persistent corneal epithelial defects did not show bacterial growth. Staphylococcus epidermidis was the most common microorganism isolated from the contaminated contact lenses.

Keratitis Due to Achromobacter xylosoxidans in a Contact Lens User

OBJECTIVES

Ocular infections due to Achromobacter xylosoxidans are extremely uncommon; their diagnosis is a challenge and the optimal treatment remains controversial. We present a case of A. xylosoxidans in a contact lens user and a review of the literature to facilitate diagnostic suspicion and empirical therapeutic management.

METHODS

Review of the literature in PubMed and MEDLINE. We also document a case diagnosed in our department in January 2016.

SETTING

Hospital Clínico Universitario Lozano Blesa, Zaragoza, Spain.

RESULTS

According to the literature, clinical manifestations and antibiotic sensitivity of A. xylosoxidans varied greatly. Our patient with no history of keratopathy presented three risk factors that made the diagnosis suspicious. The infection was resolved with topical moxifloxacin and fluorometholone.

CONCLUSIONS

A. xylosoxidans is an uncommon cause of infection, but must be suspected in atypical keratitis, reported contact with warm or still waters, use of contact lenses, or previous corneal damage. In these cases, microbiological studies and antibiotic sensitivity testing are particularly important.

Polymicrobial Infection of the Cornea Due to Contact Lens Wear

A 38-year-old male presented with pain and redness in his left eye. He had a history of wearing contact lenses. His ophthalmic examination revealed a large corneal ulcer with surrounding infiltrate. Cultures were isolated from the contact lenses, lens solutions, storage cases, and conjunctivae of both eyes and also corneal scrapings of the left eye. Fortified vancomycin and amikacin drops were started hourly. Culture results of conjunctivae of each eye and left cornea were positive for Pseudomonas aeruginosa; cultures from the contact lenses, lens solution and storage case of both eyes revealed Pseudomonas aeruginosa and Alcaligenes xylosoxidans. Polymerase chain reaction of the corneal scraping was positive for Acanthameoba. The topical antibiotics were changed with ones that both bacteria were sensitive to and anti-amoebic therapy was added. The patient had two recurrences following initial presentation despite intensive therapy. Keratitis occurred due to multiple pathogens; the relapsing course despite adequate therapy is potentially associated with this polymicrobial etiology.

Endophthalmitis caused by Achromobacter xylosoxidans after cataract surgery

PURPOSE

To report Achromobacter xylosoxidans as a cause of both acute-onset and delayed-onset postoperative endophthalmitis after cataract surgery.

METHODS

A noncomparative consecutive case series of patients with culture-proven A. xylosoxidans endophthalmitis between 1970 and 2012. Cataract surgery and intraocular lens placement were performed in all patients before endophthalmitis. Positive cultures were obtained from the vitreous, capsular bag, and/or the removed intraocular lens.

RESULTS

The clinical diagnosis was confirmed in four patients with positive cultures. Two patients with endophthalmitis had a preliminary culture report of Pseudomonas species. In addition to receiving intravitreal antibiotics, all patients underwent capsulectomy and intraocular lens removal at the time of pars plana vitrectomy. Visual acuity at last follow-up was 20/40 or better in 2 (50%) of the 4 patients, but the remaining 2 patients were 20/200 or worse.

CONCLUSION

A. xylosoxidans may be a cause of acute, recurrent, and delayed-onset postoperative endophthalmitis after cataract surgery. Complete capsulectomy and intraocular lens removal can be considered in recurrent and recalcitrant patients.

"Chemical nose" for the visual identification of emerging ocular pathogens using gold nanostars

Ocular pathogens can cause serious damages in the eye leading to severe vision loss and even blindness if left untreated. Identification of pathogens is crucial for administering the appropriate antibiotics in order to gain effective control over ocular infection. Herein, we report a gold nanostar based "chemical nose" for visually identifying ocular pathogens. Using a spectrophotometer and nanostars of different sizes and degrees of branching, we show that the "chemical nose" is capable of identifying the following clinically relevant ocular pathogens with an accuracy of 99%: S. aureus, A. xylosoxidans, D. acidovorans and S. maltophilia. The differential colorimetric response is due to electrostatic aggregation of cationic gold nanostars around bacteria without the use of biomolecule ligands such as aptamers or antibodies. Transmission electron microscopy confirms that the number of gold nanostars aggregated around each bacterium correlates closely with the colorimetric response. Thus, gold nanostars serve as a promising platform for rapid visual identification of ocular pathogens with application in point-of-care diagnostics.