MICB 202 Chapter Notes - Chapter Bacterial Disease: Gemination, Growth Medium, Bioterrorism
Document Summary
Case study #4: salmonella example of an intracellular pathogen that hides from the host"s immune defences. Intracelluar existence: many pathogens enter into host cells, and some live within phagocytic cells and others in non-phagocytic cells, intracellular pathogens divided into 2 groups: Obligate: must grow within host, cannot cultivate outside host: intracellular environment rich in nutrients, energy, shields them from host"s immune system and antibodies, complement, cell-mediated immunity plays important role in defense against intracellular pathogens. Includes t cell effector mech and activation of macrophages. Different pathogens have diff strategies: thrive in acidic environment (ex. Tuberculosis): modify vesicle membrane, resist acidification (ex. Salmonella (a genus) consists of rage of closely related bacteria: 2 species based on dna sequencing: salmonella enterica, salmonella bongori, previously disease causing species designated as serovars. Ex: salmonella typhi is now salmonella enterica serovar typhi. Diversity due to antigenic variation create variation in genes for ho, o, k antigens through recombination, alterations in length, gene duplication, point mutations.
