Exoenzymes released by bacteria include Necrotizing enzymes Coagulase Kinases

Exoenzymes released by bacteria include necrotizing

This preview shows page 9 - 18 out of 96 pages.

Exoenzymes released by bacteria include: Necrotizing enzymes Coagulase Kinases Hyaluronidase Collagenase Hemolysins Lecithinase
Image of page 9
Copyright © 2015 Wolters Kluwer • All Rights Reserved Mechanisms by Which Pathogens Escape Immune Responses Antigenic Variation Some pathogens evade the immune system by changing their surface antigens – antigenic variation ; examples, Neisseria gonorrhoeae and Borrelia recurrentis . Camouflage and Molecular Mimicry Some organisms conceal their foreign nature by coating themselves with host proteins – like camouflage (e.g., adult schistosomes). Destruction of Antibodies Some pathogens produce IgA protease, an enzyme that destroys some of the host’s antibodies; example, Haemophilus influenzae .
Image of page 10
Copyright © 2015 Wolters Kluwer • All Rights Reserved Intracellular pathogens
Image of page 11
Copyright © 2015 Wolters Kluwer • All Rights Reserved Obligate Intracellular Pathogens Pathogens that must live within host cells in order to survive and multiply are referred to as obligate intracellular pathogens (examples: Rickettsia and Chlamydia spp.). Intraleukocytic pathogens ( e.g., Ehrlichia spp. and Anaplasma phagocytophilum ) live within white blood cells, causing diseases known as ehrlichiosis and anaplasmosis. Plasmodium spp. (which cause malaria) and Babesia spp. (which cause babesiosis) are examples of intraerythrocytic pathogens; they live within red blood cells .
Image of page 12
Copyright © 2015 Wolters Kluwer • All Rights Reserved Facultative Intracellular Pathogens Facultative intracellular pathogens are capable of both an intracellular and extracellular existence. Intracellular Survival Mechanisms Possess a cell wall composition that resists digestion (e.g., Mycobacterium tuberculosis ) Fusion of lysosomes with phagosomes is prevented Production of phospholipases that destroy the phagosome membrane, thereby preventing lysosome-phagosome fusion Other unknown mechanisms
Image of page 13
Copyright © 2015 Wolters Kluwer • All Rights Reserved Burton's Microbiology for the Health Sciences Chapter 8. Controlling Microbial Growth in Vitro
Image of page 14
Copyright © 2015 Wolters Kluwer • All Rights Reserved What you absolutely must know…. Definition of microbial growth and the 8 factors that affect microbial growth Definitions of sterilization and disinfection and examples of each method The 5 most common mechanisms of action of antimicrobial agents The difference between bacteriostatic and bactericidal agents The six major categories of antibacterial agents and their mechanisms of action Mechanisms of antibiotic resistance
Image of page 15
Copyright © 2015 Wolters Kluwer • All Rights Reserved Chapter 8 Outline Introduction Factors that Affect Microbial Growth Encouraging the Growth of Microbes in Vitro Inhibiting the Growth of Microbes in Vitro
Image of page 16
Copyright © 2015 Wolters Kluwer • All Rights Reserved Factors That Affect Microbial Growth 1. Availability of Nutrients All living organisms require nutrients to sustain life.
Image of page 17
Image of page 18

You've reached the end of your free preview.

Want to read all 96 pages?

  • Left Quote Icon

    Student Picture

  • Left Quote Icon

    Student Picture

  • Left Quote Icon

    Student Picture

Stuck? We have tutors online 24/7 who can help you get unstuck.
A+ icon
Ask Expert Tutors You can ask You can ask You can ask (will expire )
Answers in as fast as 15 minutes