Ch.15 Microbial Mechanisms Of Pathogenicity Flashcards
—: the ability to cause disease
Pathogenicity
—: the degree of pathogenicity
Virulence
Seven Capabilities of a Pathogen:
1. Maintain a —
2. Leave reservoir and — host
3. — to surface of host
4. — or — of host defenses
5. — to host cells
6. — host and return to reservoir
- Reservoir
- Enter
- Adhere
- Penetration or Evasion
- Damage
- Exit
How Microoganisms Enter a Host:
~ Portals of Entry:
* ——
* —
* ——: deposited directly into tissues when Barriers are —
- Mucous Membranes
- Skin
- Parenteral Route, Penetrated
How Microoganisms Enter a Host:
~ Most pathogens have a — portal of entry
~ The most common portals of entry are the same —— colonized by —
- Preferred
- Anatomical Surfaces, Microbiota
Numbers of Invading Microbes:
~ ID50: —— for —% of a sample population
* — of — required to cause infection in 50% of subjects (test animals)
* Measures — of a microbe
- Infectious Dose for 50%
- Number of Cells
- Virulence
LD50: —— for —% of a sample population
* — of — required to cause — in 50% of the subjects
* Measures — of a —
* A — virulent pathogen has a — value of ID50 and LD50 than does a — virulent one
- Lethal Dose, 50%
- Number of Cells, Death
- Potency of a toxin
- Highly, Lower, Moderately
Vibrio cholerae causes —
* It requires very large infective dose (10^7) because V.cholerae is easily destroyed by ——
- Cholera
- Stomach Acid
— requires a very — infective dose as few as 50-300 organisms can cause disease
- Shigella
- Small
Adherence:
~ Almost all pathogens attach to host tissues in a process called —
~ — on the pathogen bind to — on the host cells
* — & —
~ Microbes form — (communities that share nutrients)
- Adherence (adhesion)
- Adhesins (ligands), Receptors
- Glycocalyx & Fimbriae
- Biofilms
Capsules:
~ — around the cell wall
~ Impair —
* Streprococcus pneumonia: —
* Haemophilus influenza: — & —
* Bacillus anthracite: —
* Yersinia pestis: —
- Glycocalyx
- Phagocytosis
- Pneumonia
- Pneumonia & meningitis
- Anthrax
- Plague
Cell Wall Components:
~ —— resists phagocytosis
* ——
- M protein
- Streptococcus pyogenes
Cell Wall Components:
~ —— allows attachment to host cells
* ——
- OPA Protein
- Neisseria gonorrhoeae
Cell Wall Components:
~ —— resists digestion
* ——
- Waxy lipid (mycolic acid)
- Mycobacterium Tuberculosis
Enzymes:
~ —: coagulate fibrinogen
Coagulases
Enzymes:
~ —: digest fibrin clots
Kinases
Enzymes:
~ —: digest polysaccharides that hold cells together
Hyaluronidase
Enzymes:
~ —: break down collagen
Collagenase
Enzymes:
~ ——: destroy IgA antibodies
IgA Proteases
Streptokinase:
~ Used streptokinase to successfully treat ——-. Became the mainstay for ——— when FDA approved its use
- Coronary Artery Blockage
- Digesting Blood Clots
Antigenic Variation:
~ Pathogens alter their —— (and — are rendered ineffective)
- Surface Antigens
- Antibodies
Antigenic Variation:
~ A wide range of microbes is capable of antigenic variation. Examples include
* ——; the causative agent of —
* ——; the causative agent of —
- Influenza Virus, Influenza (Flu)
- Neisseria gonorrhoeae; gonorrhea
Penetration into the Host Cell Cytoskeleton:
~ Invasins: —— produced by bacteria that rearrange ——. Of the cytoskeleton
* Cause membrane ruffling, is the result of — in the cytoskeleton
* Microbes sink into the ruffles and are — by the host cell
~ Use — to move from one cell to the next
* — and —
- Surface Proteins
- Actin Filaments
- Disruption
- Engulfed
- Actin
- Shigella & Listeria
Using the Host’s Nutrients: Siderophores
~ — is required for most pathogenic bacteria
~ Siderophores are — secreted by pathogens that bind — more tightly than host cells
- Iron
- Proteins, Iron
Direct Damage:
~ Disrupts host cell —
~ Uses host cell —
~ Produces ——
~ — in host cell and causes —
- Function
- Nutrients
- Waste Products
- Multiple, ruptures
Production of Toxins:
~ Toxins: — substances produced by —
* Produce —, — problems, —, and —
- Poisonous, microorganisms
- Fever, Cardiogenic, diarrhea, shock
Production of Toxins:
~ Toxigenicity: — of a microoganisms to produce a —
- Ability
- Toxin
Production of Toxins:
~ Toxemia: — of — in the host’s —
- Presence of Toxin
- Blood
Production of Toxins:
~ Intoxications: — of — without ——
- Presence of toxin
- Microbial growth
Exotoxins:
~ — produced and secreted by —
* Soluble in ——; destroy —— and inhibit ——
~ Exotoxins are among the most — substances known
- Proteins, bacteria
- Bodily fluids, hosts cells, metabolic functions
- Lethal
Exotoxins:
~ Antitoxins: — against — exotoxins
- antibodies
- Specific
Exotoxins:
~ Toxoids: — exotoxins used in —
- Inactivated
- Vaccines
Exotoxins:
~ —— toxins lyse host cells by disrupting plasma membranes
* Leukocidins: kill ——
* Hemolysins: kill — by forming ——
* Streptolysins: — produced by —
- Membrane disrupting
- Phagocytes leukocytes
- Erythrocytes, protein channels
- Hemolysins, streptococci
Exotoxins:
~ Superantigens cause an ——— due to the release of — from host cells (T cells)
* Cause symptoms of —, —, —, —, —, & —
- Intense immune response
- Cytokines
- Fever, nausea, vomiting, diarrhea, shock, and death
Exotoxins:
~ Genotoxins damage — ( causing —, disrupting ——, and leading to —)
- DNA
- Mutations
- Cell Division
- Cancer
Endotoxins:
~ —— portion of lipolysaccharides (LPS) of —— bacteria
~ Released during bacterial — and when gram — bacteria —
* Stimulate macrophages to release —
* Cause ———
- Lipid A, Gram Negative
- Multiplication, negative, die
- Cytokines
- Disseminated intravascular coagulation
Portals of Exit:
~ Respiratory tract: — and —
~ Gastrointestinal tract: — and —
~ Genitourinary tract: —; secretions from penis and vagina
~ —
~ Blood: — that bite, — or —
- Coughing and Sneezing
- Feces and Saliva
- Urine
- Skin
- Arthropods, needles or syringes
