Microbes and humans Disease can come about in several overlapping ways 1. Entirely adapted to the pathogenic way of life in humans, and never be part of the normal flora but may cause subclinical infection, e.g. M.tuberculosis 2. Part of the normal flora acquire extra virulence factors making them pathogenic, e.g. E. coll 3. Part of the normal flora can cause disease if they gain access to deep tissues by trauma, surgery, lines, e.g.s epidermIdIS 4. In immunocompromised patients many free-living bacteria and components of the normal flora can cause disease, especially if introduced into deep tissues, e.g AcinetobacterMicrobes and humans Disease can come about in several overlapping ways 1. Entirely adapted to the pathogenic way of life in humans, and never be part of the normal flora but may cause subclinical infection, e.g. M . tuberculosis 2. Part of the normal flora acquire extra virulence factors making them pathogenic, e.g. E. coli 3. Part of the normal flora can cause disease if they gain access to deep tissues by trauma, surgery, lines, e.g. S. epidermidis 4. In immunocompromised patients many free-living bacteria and components of the normal flora can cause disease, especially if introduced into deep tissues, e.g. Acinetobacter