The host responses or the major inflammatory cascades produce many substances that, in addition to eradicating the organism, can also cause damage and facilitate spread in the host tissue, D Amico said. Some therapies, notably antibiotics and other drugs, can create additional factors that could cause damage. These not only kill the organism and break them into constituent parts that may be secondarily inflammatory, but they may also alter structures so that inflammation and damage are enhanced, he said. Host factors, such as diabetes, predispose a patient to infection. Surgery and nonsurgical trauma with the obliteration and alteration in tissue anatomy are also factors in endophthalmitis.
Many organisms encountered in ophthalmic endophthalmitis are low-virulence organisms.
Our most typical endophthalmitis cases seem to be of exceptionally low virulence. We can eradicate these even in the presence of retained intraocular lenses, he said. Candida is a low-virulence organism in most situations. However, when fungi become invasive locally, they can be impossible to eradicate. High-virulence situations, like Staphylococcus aureus, streptococci, enterococci, and Bacillus cereus, also occur.