The influence of pili on the attachment of Moraxella bovis to bovine corea as seen with scanning electron microscopy

The purpose of this study was to more clearly define the role pili play in the attachment of Moraxella bovis to corneal tissue. By treating freshly collected cornea in various ways and examining the results with the techniques of scanning electron microscopy, it was possible to obtain a more accurate picture of the pathogenic process.

It was found there is a significant difference in the number of bacteria that attach to bovine corneal tissue when piliated vs. nonpiliated bacteria were used. Pretreating the bacterial cells by heating them severely damaged their pili and greatly reduced their attachment. Pretreatment with formalin, however, had no effect on the pili or the attachment of the bacteria to the corneal epithelial tissue. No attachment was seen when rabbit and canine cornea were examined under identical conditions. Finally, pretreatment of the bovine cornea with purified pili before exposure to the organism significantly reduced the number of attaching bacteria.