Opportunistic microorganism

The external surfaces of the normal, fit, healthy human being have evolved to be effective barriers against penetration by opportunistic microorganisms to internal tissues that might provide them with nourishment at the expense of the host. Sometimes the external physical barriers fail, and then other antimicrobial defense mechanisms come into play, the immune system for instance. These internal mechanisms are combating infection. The various symptoms of infectious disease are the result of the interaction between the attempts by the infecting agent to colonize the internal tissues of the body and the attempts by the body s defense mechanisms to overcome this invasion. 

Physiological (including emotional/mental states) susceptibility of the patient to the infectious opportunistic microorganism... 

I. PHYSIOLOGICAL SUSCEPTIBILITY OF A PATIENT TO AN INFECTIOUS OPPORTUNISTIC MICROORGANISM... 

Endogenous Infection An infection caused by opportunistic microorganism already present in the body. 

The isolation of a particular microorganism fiem a markedly spoiled product does not necessarily mean that it was the initiator of the attack. It could be a secondaiy opportunist contaminant which has overgrown the primary spoilage organism once the physico-chemical properties had been favourably modified by the primary spoiler. 

Any microorganism may be opportunistically pathogenic if administered parenterally or if applied to susceptible tissues (the transparent parts of the eye have a particularly poor blood supply and, therefore, a less sensitive immunological response than do other parts of the body) or to debilitated or immunocompromised patients. 

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