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Pseudomonas aeruginosa infection of human cornea is rare but serious. The work of previous investigators using experimental infection primarily of rabbit cornea resulted in successful therapy for 10 to 50% of clinical cases. The advantage of using the mouse is demonstrated. The methods we adapted for characterizing the untreated experimental infection included: incising the cornea to enable establishing the infection; corneal examination with a steroscopic microscope; grading corneal pathology; qualitative and quantitative monitoring of the infecting bacteria by culturing and staining sectioned and dissected tissues. The characteristics of the tissue pathology, host response, and infection were similar to those reported for other animals and man. Corneal pathology was frequently nearly maximal 1 day after infection; host response involved a progression of events of long duration; pathology persisted well beyond the period of bacterial infection. The infection was essentially noncommunicable, and invasiveness was limited to the tissues of the incised eye. The results show the possibility of tests for invasiveness of clinical isolates and for screening for therapeutic and prophylactic measures.

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In developing the microbiological assay for nystatin1 in feeds, reported by Pagano, studies were made of the following factors: effect of heat and of pH on nystatin stability; effect of solvents on nystatin recovery; effect of feed extractives on Candida tropicalis; recovery of nystatin at different concentrations in feed; and preparation of a nystatin-free feed. Heat and pH must be rigidly controlled to keep nystatin loss at a minimum. Best recoveries were obtained with a hexane wash and methanol extraction.

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