Q-248. Contact Lens Wear and Mycotic Keratitis Outbreak 2005-2006: Why Fusarium?

D. G. Ahearn1, S. Zhang1, R. D. Stulting2;
1Georgia State Univ., Atlanta, GA, 2Emory Univ., Atlanta, GA.

Background: Fusarium solani (FSSC) and F. oxysporum (FOSC) complexes were almost exclusively isolated as the contaminants from the hydrogel contact lens cases of patients in the 2004-2006 ReNu with MoistureLoc (RML)-associated Fusarium keratitis outbreak. The environment of the patient was identified as the source of the contamination. Why were fusaria isolated to the exclusion of other organism? Methods: Four multipurpose contact lens solutions (MPS) including RML were evaporated in a laminar flow hood for one to four hours, inoculated with selected fusaria from keratitis patients, then evaporated for 20 h. Unused RML was challenged with the fusaria and Pseudomonas aeruginosa. The effect of RML on the attachment of P. aeruginosa and other bacteria on to the etafilcon A hydrogel lens was examined. Data on attachment and surviving microorganisms were interpreted in reference to published outbreak data. Results: Fresh MPS was inhibitory for both fusaria and bacteria. Only sparse numbers of F. solani GSU AFR4 and, to a slightly greater extent, F. oxysporum GSU AFR9, however, survived drying in MPS. Conclusions: The near exclusive contamination by fusaria of lens cases from patients with RML-associated keratitis is, in part, attributed to somewhat unique survival characteristic of the fusaria and their interactions with stressed MPS, particularly RML. Representatives of the FSSC, the major complex associated with the recent Fusarium keratitis outbreak, and of the secondarily involved FOSC, survived drying in RML, had potential for rapid amplification during the drying process (microcycle conidiation), and the ability to adhere firmly to and penetrate various hydrogel lenses. These properties are hypothesized to have been expressed in the presence of the RML formulations under stress environmental conditions inhibitory for common bacteria and fungi.

181/Q. Indicators of Fecal Pollution - I

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