Prescrire les collyres fortifiés

Successful treatment of Keratitis caused by Mycobacterium chelonae and an overview of previous cases in Europe

INTRODUCTION AND PURPOSE

Mycobacterium (M.) chelonae is responsible for a half of relatively rare nontuberculous mycobacteria (NTM) keratitis. We report a case of M. chelonae keratitis in a woman following sclerocorneal suture extraction after cataract surgery.

RESULTS

A 70-year-old woman presented with a red eye and corneal infiltration of her left eye six weeks following sclerocorneal suture extraction after an elective cataract surgery in another institute. She complained of a sharp, cutting pain and photophobia. Since initial corneal scrapes and conjunctival swabs proved no pathogen using culture and PCR methods, non-specific antibiotics and antifungal agents were administered. As keratitis was complicated by an inflammation in the anterior chamber and vitreous, samples of the vitreous fluid were sent for microbiologic examination. DNA of Epstein-Barr virus (EBV) was repeatedly detected. Since the intrastromal abscess had formed, corneal re-scrapings were performed and M. chelonae was detected using culture, MALDI-TOF MS and PCR methods. Therapy was changed to a combination of oral and topical clarithromycin, intravitreal, topical and intracameral amikacin, and oral and topical moxifloxacin. The successful therapy led to stabilization. The optical penetrating keratoplasty was performed and no signs of the infection recurrence were found.

CONCLUSIONS

The diagnosis of nontuberculous mycobacterial keratitis is difficult and often delayed. An aggressive and prolonged antimicrobial therapy should include systemic and topical antibiotics. Surgical intervention in the form of corneal transplantation may be required in the active and nonresponsive infection. In the presented case this was necessary for visual rehabilitation due to scarring.

[Bacterial keratitis : Clinical aspects, pathogens and treatment]

Bacterial infections are by far the most frequent cause of infectious keratitis in high-income countries. The clinical appearance can vary widely depending on the type and species of bacteria, ranging from small superficial infiltrates to necrotizing forms. The numerous classes of available antibiotics render the treatment scope diverse and complex, especially before the pathogen has been specified and the sensitivity to antibiotics has been tested. New therapeutic approaches to reduce bacterial virulence are in development. This CME article focuses on the clinical, diagnostic and therapeutic approaches to recognize and treat bacterial keratitis.

[Influence of frequent instillations of anti-infective solutions on eye tissues (an experimental study)]

PURPOSE

To investigate the toxic effects of frequent instillations of anti-infective solutions (antibiotic eye drops - 0.3 and 1.4% tobramycin, 0.5% levofloxacin and 0.5% moxifloxacin; antiseptic eye drops - 0.05% pyloxidine and 0.025% chlorhexidine; antifungal drug - 2 mg/ml fluconazole solution) on ocular tissues.

MATERIAL AND METHODS

The study was conducted on 21 Wistar rats (42 eyes) using method of semi-fine sections.

RESULTS

The majority of antibiotics and antifungal agents do not cause toxic reactions in rats` eyes when instilled with frequent regimen with the exception of 'fortified' 1.4% tobramycin and pyloxidine solutions, which caused a decrease in corneal endothelial cells density and formation of fibrovascular tissue in the anterior chamber.

CONCLUSION

Frequent instillations of antimicrobial drug solutions is a safe method for the treatment of purulent corneal ulcers and purulent keratitis. The exceptions were solutions of 'fortified' 1.4% tobramycin and piloxidine (vitabact).

[Purulent corneal ulcers: clinical presentation, diagnosis, and conservative treatment]

This is a detailed review of purulent corneal ulcer signs and symptoms, problems in diagnosis, and conservative treatment options.

[Fortified antibiotic (vancomycin, amikacin and ceftazidime) eye drop stability assessment at -20 degrees C]

INTRODUCTION

Fortified antibiotic ophthalmic solutions are regularly administered as an immediate treatment for bacterial keratitis. Fortified antibiotics used to be self-prepared by nurses. To solve this problem, pharmacy staff studied the stability of three 5% solutions of vancomycin, amikacin, and ceftazidime prepared in aseptic conditions from parenteral antibiotic solutions.

MATERIAL AND METHODS

Solutions were frozen at -20 degrees C. Each solution were examined before storage and over a 75-day period. Ceftazidime and amikacin were diluted in 0.9% sodium chloride and vancomycin in 5% dextrose. Over a 75-day period, physical and pharmacological (absorbance spectra) properties and the sterility of each stock solution were studied.

RESULTS

The pH of amikacin (6.51), ceftazidime (6.47), and vancomycin (3.77) remained stable during the 75-day period. Osmolarities also remained stable (367, 488, and 351 mOsm/L, respectively). There were no significant differences in the concentration, osmolarity, and pH of the three antibiotic solutions before storage and after 75 days of freezing. Over a 75-day period, the stability of amikacin, ceftazidime, and vancomycin remained constant; no contamination was detected before storage and after 75 days.

CONCLUSION

Topical fortified antibiotic solutions can be stored for 75 days at -20 degrees C (15 days quarantine). After this time, these eye-drops should be stored at 4 degrees C and should be discarded after 3 days.