Unformatted text preview: ed Host Compromised Host has lowered resistance to infection and ultimately disease. Malnutrition, Alcoholism
Trauma from surgery or an injury
Cancer or leukemia
Immunosuppressant drugs, viruses like HIV, genetic deficiencies
Altered normal flora due to antibiotics Infection and Disease
Infection and Disease
• • •
• • Infection refers to any situation in which a microorganism is established and growing in or on a host, regardless of whether or not the host is harmed !!
Disease is damage or injury to the host that impairs host function
Infection is not synonymous with disease
Normal flora can sometimes cause disease if the host resistance is compromised
Infestation: Presence of organism; not necessarily growing & reproducing TABLE 21.1 Representative genera of microorganisms in the normal flora of humans Anatomical site Organism Skin Staphylocuccus, Corynebacterium, Acinetobacter, Pityrosporum (yeast) , Propionibacterium, microcuccus Mouth Streptococcus, Lactobacillus, Fusobacterium, Veillonella, Corynebacterium, Neisseria, Actinomyces Respiratory Tract Streptococcus, Staphlococcus, Corynebacterium, Neisseria Gastrointestinal tract Lactobacillus, Streptococcus, Bacteroides, Bifidoacterium, eubacterium, Peptococcus, Peptostreptoccus, ruminococcus, Clostridium, Escherichia, Klebsiella, Proteus, Enteroccus, Staphylococcus Urogenital tract Escheicia, Klebsiella, Proteus, Neisseria, Lactobacillus (vagina of mature females)
, Corynebacterium, Staphylococcus, Candida, Provotella, Clostridium, Normal Flora
Normal Flora Skin: 1012 bacteria; apocrine (sweat) glands & sebaceous (lubricant: oil) glands of hair follicles
Internal tissues: brain, blood, cerebrospinal fluid, musclesno bacteria
StomachpH around 2; acidity drops viable count to <10/mL. (chemical barrier). Mycobacteria, Salmonella are resistant. Also, Helicobacter pylori: ulcers
Colon: adult eliminates about 3 x 1013 microbes daily.
Genitourinary Tractupper [kidney, ureters, & urinary bladder] is free of microbes.
Upper (nasopharynx, oral cavity, larynx and pharynx): restricted # colonizes. Lower respiratory tracts (trachea, bronchi, bronchioles, alveoli) do not have normal flora. Mucus traps microbes, ciliated epithelium cells move it up and out (excreted in saliva and nasal secretions), and finally bactericidal effect of lysozyme. • •
• Exposure and Entry: Portals of Entry Adherence
Virulence factors produce damage ie. Disease. I. Portals of Entry
I. Portals of Entry Food and Water Bourne: Staphylococcus, Vibrio cholera, Clostridium botulinum, Salmonella
Exhalation Droplets: coughing & sneezing Mycobacterium tuberculosis ; viruses; Direct Contact: mononucleosis, syphillis, Herpes, HIV [Retrovirus], Chlamydia
Indirect Contact: mononucleosis, flu & cold viruses, often hand to hand contact & hand contacts eyes
Animal Bite or Scratches: rabies, cat scratch fever
Parenteral (wound or puncture): penetration of skin or mucus membranes due to puncture Vector transmitted: LYME DISEASE, Rocky Mt. spotted fever, bubonic plague (Yersinia pestis), malaria How Microbe...
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- Fall '13
- Virulence factors, Protein biosynthesis, elongation factor