Lecture Microbiology - Chapter 14: Host- microbe relationships and disease processes. This chapter presents the following content: Symbiotic relationships, host invasion, pathogenicity determinants, microflora, opportunism, koch’s postulates,. | HOST- MICROBE RELATIONSHIPS AND DISEASE PROCESSES CHAPTER 14 Copyright © 2012 John Wiley & Sons, Inc. All rights reserved. Symbiotic Relationships Mutualism – Microbe benefits – Host benefits – E. coli in intestine Parasitism – Microbe benefits – Host is damaged – All pathogens Commensalism – Microbe benefits – No effect on host – Corynebacterium in eye Copyright © 2012 John Wiley & Sons, Inc. All rights reserved. Host Invasion Contamination – Presence of microbes Infection – Invasion or colonization by microbes Disease – Change away from a normal state of health Copyright © 2012 John Wiley & Sons, Inc. All rights reserved. Pathogenicity Determinants Microbial count Virulence / Avirulence Attenuation Virulence Transposition via infection of novel hosts • Rabies vaccine Copyright © 2012 John Wiley & Sons, Inc. All rights reserved. Microflora 1014 microbes versus 1013 body cells Colonization Non-sterile areas Sterile areas Resident microflora Transient microflora Copyright © 2012 John Wiley & Sons, Inc. All rights .