Abstract
Purpose::
To survey used bottles of moxifloxacin and gatifloxacin for fungal contamination.
Methods::
Thirty-four bottles of topical moxifloxacin and gatifloxacin returned after use by either keratitis patients or post-op cataract patients were sampled for fungi in the following ways. The inside of the bottle cap and the outside of the bottle spout were sampled with sterile cotton swabs pre-moistened with sterile double distilled water and the swabs were streaked on Sabouraud’s agar. The inside of each bottle was sampled in one of two ways. Antibiotic solution was dripped onto agar or, when the bottle was empty, it was sliced open with a sterile blade and the inside wall sampled with sterile cotton swabs pre-moistened with sterile double distilled water and streaked onto agar plates. All plates were incubated at room temperature and examined periodically up to one month for fungi. Identification of fungi was determined by either morphological characteristics alone or in combination with molecular methodology by ITS sequence comparison.
Results::
The proportion of bottles that contained fungal contamination in any area was significantly greater for the moxifloxacin 0.5% bottles than the gatifloxacin 0.3% bottles (P = 0.028). Fungi isolated from 12 moxifloxacin 0.5% spouts and 2 gatifloxacin 0.3% spouts (P = 0.039) as well as 7 moxifloxacin 0.5% caps and 1 gatifloxacin 0.3% cap (P = 0.142) were also greater for moxifloxacin. The inside of 2 moxifloxacin 0.5% bottles were positive for fungi while no bottles of gatifloxacin 0.3% were positive for fungi (P = 0.521). The fungi identified included Cladosporium sphaerospermum, Penicillium chrysogenum, Acremonium minutisporum, Nigrospora oryzae, Aspergillus sp., Debaryomyces hansenii var hansenii, Engyodontium album, Epicoccum nigrum, Nigrospora oryzae, and Penicillium decumbens.
Conclusions::
Our results demonstrate that topical gatifloxacin 3.0% is more resistant to fungal contamination than topical moxifloxacin 0.5%. Normal usage of topical therapeutic solutions may require the inclusion of selected preservatives to inhibit the growth of microbial contaminants.
Keywords: antibiotics/antifungals/antiparasitics • fungal disease • bacterial disease