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Microbiology Chapter 27 Vocab

Terms in this set (68)

In-Utero
No Microbes but at birth begin normal flora that do NOT produce disease under normal conditions.
Mutualism
both HOST and MICROBE benefit
Commensalism
NO DAMAGE TO HOST
Parasite (parasitism):
microbe causes damage to host
Pathogenic relationship
microbe causes damage to host
Normal flora
microorganisms normally found in or on the body that typically DO NOT cause disease
Synergistically
working together; 2 microorganisms are synergistic if they are able to produce a host response MORE than the sum of the effects they produce when acting alone
Communicable
able to be transmitted between hosts
Disease reservoir
a natural source of disease agent; may include sick patients, asymptomatic carriers, animals, recovered patients, environmental sources, etc
Pathogens
Microbial parasites
virulence / LD50
The amount of degree/severity of pathogenicity.
The # to elicit disease in host within a period of time
Streptococcus pyogenes
causes strep throat & is a pathogen
Candida albicans
normally a commensal, causing no damage to host
compromised host
has lowered resistance to infection and ultimately disease
Malnutrition, alcoholism
Trauma from surgery or an injury
Cancer or leukemia, Diabetes
Immunosuppressant drugs, viruses like HIV, genetic deficiencies
Altered normal flora due to antibiotics
Infection
where a microorganism is and growing in or on a host, regardless of whether or not the host is harmed. So it just where a microorganism grows, may be harming but may not be,
Disease
damage or injury to the host that impairs host function
Infestation
is the presence of an organism, not necessarily growing and/or reproducing
Skin
apocrine/sweat and sebaceous/oil glands of hair follicles - 10^12 bacteria
Internal tissues
brain, blood, cerebrospinal fluid, muscles - no bacteria
Stomach
pH around 2; acidity drops viable count to <10/mL, creating a chemical barrier. Mycobacteria, Salmonella are resistant
Helicobacter pylori --> ulcers
Colon
adult eliminates about 3 x 10^13 microbes daily
Upper genitourinary tract
kidney, ureters, & urinary bladder - no microbes
Upper respiratory system
nasopharynx, oral cavity, larynx and pharynx) - restricted # colonize
Lower respiratory system
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
Food and water Bourne
Staphylococcus, Vibrio cholera, Clostridium botulinum, Salmonella
Exhalation droplets
coughing & sneezing, Mycobacterium tuberculosis
Direct Contact
mononucleosis, syphillis, Herpes, HIV [Retrovirus], Chlamydia
Indirect Contact
mononucleosis, flu & cold viruses, often hand to hand contact and 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 Mountain spotted fever, bubonic plague (Yersinia pestis), malaria
Mucuous membranes include
Respiratory track
GI track
Genourinary
Respiratory track
microbes inhaled into nose or mouth in drops of moisture or dust particles (exhalation droplets)
Example: Common cold, influenza, pneumonia, measles
GI track
food, water, and contaminated fingers
Example: Cholera, dysentery, typhoid, Salmonella food poisoning
Genourinary
Typically sexually transmitted
Example: HIV, syphillis, gonorrhea, herpes
Tissue selective
Neisseria gonorrhoeae adheres more strongly to urogenital epithelium (tissue specificity)
Opa surface protein binds with host CD66 protein.
Host Selectivity
a microorganism that normally infects humans binds to human epithelial cells better than those of a rat
colonization and growth
The microbe may then may establish itself, grow, and multiply
Virulence
Invasiveness: grow in large numbers and may spread throughout host body
Toxigenicity
toxins that inhibit host cell function or kill host cells
Two types: Exotoxins and Endotoxins
Resistance
Acquired or Induced Immunity
Humoral Immunity
mediated by antibodies
Cellular Immunity
mediated by cells (T cells)
Natural Resistance or Innate Immunity
Cells: macrophages
Mechanical Barriers: skin and mucous membranes
Chemical Factors: interferon, fatty acids on skin
Microbial Factors: Normal flora competition
Hyaluronidase
spreading factor
catalyzes the breakdown of hyaluronic acid, the substance that cements the human cells together
Allows the bacterial cells to spread through tissue causing cellulitis
Example: Staphyloccus, Streptococcus, Clostridia
Coagulase
enzyme catalyzes the conversion of fibrinogen to fibrin with resultant clot formation
Present in pathogenic Staphyloccus
Fibrinolysin
enzyme catalyzes the conversion of plasminogen to the fibrinolytic enzyme plasmin, acts opposite of coagulase
In Staphylococcus aureus, the gene for fibrinolysin is on a bacteriophage and is expressed during lysogeny
Lipase
production of excessive amounts of lipase allow bacteria to penetrate fatty tissue with the consequent formation of abscesses
CollagenASE
enzyme catalyzes the degradation of collagen, a protein found in tendons, nails and hair
Leukocidins
lysis of white blood cells
Example: Staphyloccus aureus
StreptokinASE and StreptodornASE
actually fibrinolytic enzymes (category 3)
LecithinASE
enzyme that destroys red blood cells and other tissue cells
Hemolysins
lyse red blood cells
Capsule
carbohydrate or protein coat-adherence, antiphagocytic
Pili and fimbriae
attachment to surface receptors on host cells
Example: urinary tract infections
Flagella
motility
Enzymes to breakdown clots
StreptokinASE and StreptodornASE (fibrinolytic)
Enzymes to inhibit clotting machinery
Strep throat necrotizing fasciitis (flesh eating bacteria)
Necrotizing fasciitis is worst case
Genetic predisposition? Severe disease may depend on immunogenetics of the patient
Clostridia
food poisoning (botulinum) gas gangrene (death and putrefaction of tissue, bubbles of gas in decomposing tissue)
Widespread and destroys tissue (contrast with later C. tetani
Invasiveness
is the ability of an organism to grow in host tissue
Toxicity
the ability of an organism to cause disease by means of a preformed toxin that inhibits host cell function or kills host
Cytolytic toxins
Type of Exotoxin
(include hemolysins): damage cell membranes, causing cell lysis & death (also are a subcategory of cytotoxins,
A-B toxins
Type of exotoxin
B promotes specific binding of toxin to host cell receptor (allows transfer of A (toxic part) across targeted cell membrane).
Superantigen toxins
type of exotoxin
large numbers of immune lymphocytes and causes systemic & inflammatory responses. Extensive inflammation & tissue damage
Edema factor (EF)
Causes swelling
Lethal Factor(LF)
Causing cell death
Enterotoxins
alters permeability of intestinal epithelium causes massive secretion of fluid into the intestinal lumen causing diarrhea
endogebous pyrogens
Causes fever
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