**21. Conclusion**

The relationship between microorganisms has a long evolutionary history. The ability of microorganisms to interact conferred the possibility to collaborate and to adapt within a wider spectrum of environmental conditions. These circumstances have a direct impact on the clinical presentation as well as the dynamics of infection in the population.

Delay in diagnosis affects the sensitivity to specific treatments and the evolution of infection. The rate of recovery could be slow and morbid, leaving serious sequelae with the risk of loss of vision. Advances in methods for detecting infectious organisms and molecular microbiology have facilitated the recognition of the interactions among pathogens found in coinfections in the human eye. The acute period of coinfection is determinant to identify the coinfecting microorganisms. Awareness in the medical field and particularly in ophthalmology of lesions that do not cover the conditions of a pathognomonic clinical picture should be resolved with molecular biology techniques together with classical techniques of microorganism recognition, until final identification, if possible.

In this chapter, we proposed a strategy for reducing the uncertainty of the presence of two or more microorganisms affecting the eye. This has been implemented in our laboratory and has increased the possibility of isolation and identification.

In addition, the biofilm of each combination of pathogens must be studied molecularly to understand its particular adhesion and aggregation, possible mutations, and strategies for evasion or elimination of antimicrobial. Together with pharmacodynamics, *in vivo* studies will facilitate the application of different antimicrobial dosages to successfully remove coinfecting microorganisms.
