Introduction to Microbiology and Disease
Terms
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- What is bacteria?
- Simple celled micro organism that is found everywhere.
- Pathogenic bacteria...
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Causes disease
i.e. Strep throat, meningitis - What is a virus?
-
Not a cell - smaller/simpler
Need a host to live
i.e. AIDS, chicken pox - What are protozoa?
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Single celled animal amoeba
Free living in fresh/salt water
Eat fungi, bacteria, etc
i.e. malaria - Define fungi
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Uni or multi cellular
Decompose organic matter/help recycle nutrients
i.e. mold, mushrooms - Worms are...
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Multi cellular
Free living, non pathogenic
Found in soil, dead matter, smaller living things - Genus
- First, capitalized, larger
- Species
- Second, not capitalized, smaller
- Normal Flora
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Micro organisms that live on and in us
Non-pathogenic - Resident Flora
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Live on/in us...nearly everyone almost all the time
Ex. E-coli - Opportunist
- Harmless species - can become pathogen in special circumstances
- Transient Flora
-
Found in/on body - micro - not adapted
Can cause harm - Infectious disease
- Caused by micro organisms (pathogens) or by products (toxins)
- Virulence
- Ability of the pathogen to cause disease
- Resistance
- Bacteria are able to produce an enzyme
- Defenses against pathogens
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-Intact skin
-Mucus membrane
-Sweeping cillia
-Adaquet nutrition
-Immunity - Clinical
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Measurable signs
Ex. fever - Sub-clinical
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No symptoms
Ex. HIV+ - Reservoirs
- Source of infection
- Course of infectious disease
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-Incubation
-Prodromal
-Self limiting - Incubation
- Before symptoms occur
- Prodromal
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Vague symptoms
Ex. cold - Self limiting
- Lasts a certain length of time
- Types of infection
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-Localized
-Systemic
-Bacteremia and septicmia
-Acute
-Chronic
-Secondary
-Nosocomial
-Endogenous - Localized Infection
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Continued in one area of the body
Ex. throat infection - Systemic Infection
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Throughout body
Ex. lymph/blood - Bacteremia and septicmia
- Microbes in the blood - large amount
- Acute Infection
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Begins suddenly - severe
Ex. appendicitus - Chronic Infection
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Slow, around for a long time
Ex. Mononucleosis - Secondary Infection
- Made possible by a primary infection that has lowered host resistance
- Nosocomial Infection
- Acquired in hospital/nursing home
- Endogenous Infection
- Nosocomial infection caused by patient's normal flora
- Epidemiology
- Study of the patterns and spread of disease within a population
- Epidemic
- An outbreak of disease
- Endemic
- Disease that is present in a population with an expected number of cases
- Pandemic
- Epidemic that will spread to several countries
- Portal of Entry
-
The way pathogens enter the host
-Natural body openings (mouth,anus,vagina,urethra)
-open skin,inhalation,sexual activity - Portal of Exit
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The way pathogens leave the body
-Urine, feces, sexual activity, coughing droplets - Reservoirs of Infection
- Some can only cause disease in people - disease is residing
- Carrier
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Carries the disease out
No symptoms - Zoonoses
- Carries disease from animals to people
- Spread of Infection
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*Non-communicable
*Communicable
*Fomite
*Contagious - Non-communicable
- Resident species causes disease under certain conditions or in which a non-resident species causes disease when it enters the body
- Communicable
- Pathogen may be transmitted directly or indirectly from host to host
- Fomite
- Inanimate object that carries the disease
- Contagious
- Spreads very easily
- Methods to Control of Microbes
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-Antiseptics
-Disinfectant
-Bactericide
-Bacteriostatic - Antiseptic
- Chemical that destroys bacteria or inhibits their growth in a living being (skin surface)
- Disinfectant
- Chemical that is used on inanimate objects
- Bactericide
- Kills bacteria by disrupting important metabolic processes
- Bacteriostatic
- Chemicals do not destroy bacteria - stops reproduction
- Sterilization
- Process that destroys all living organisms
- Autoclave
- Chamber in which steam is generated under pressure
- Public Health Measures
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-Emerging diseases
-Safe food/drinking water
-Prepare defense against use of biological weapons - Pathogens - bacteria
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-Prokaryote
-Eucaryote - Prokaryote
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No definite organelles
Ex. bacteria - Eucaryote
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Definite organelles
Ex. human cell - Classification of Bacteria
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-Morphology
-Staining
-Mobility
-Growth
-Atmospheric conditions
-Nutritional requirements
-Biochemical/metabolic activities
-Pathogenicity
-Amino acid sequencing of proteins - Morphology
- Classification of bacteria
- Staining
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Gram +,-
Used to identify bacteria by thickness of cell wall - Mobility
- How they move
- Growth
- How they reproduce
- Atmospheric Conditions
- Whether it needs oxygen or not
- Nutritional Requirements
- What it needs to grow/substain life
- Biochemical and Metabolic Activities
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How fast it grows/reproduces
Ex. toxins/endotoxins - Pathogenicity
- Whether or not it causes disease
- Amino Acid
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Subunit of a protein
C H O N - Capsule
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-Seen in bacilli/coccus
-Gelatnous sheath that closes the entire cell
-Inhibits phagocytosis
-Protects bacteria - Spore
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-Hard shell
-Allows micro organisms to lay dormant - Toxins
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-Chemical produced by
-Harmful to host tissue
-Bacteria produces secretion - Neurotoxins
- Special chemicals - harm nerve tissue
- Endotoxins
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Gram - bacteria
-Causes fever/circulatory shock
-Drop of blood sugar - Rickettsia
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-Obligate intracellular parasites
-Reproduce only within living cell of the host parasites of mammals including people
-Spread by anthropod vectors
Ex. lyme disease - Chlamydia
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-Sexually transmitted disease
-No symptoms
-Causes sterility - Antibiotics
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-Chemicals that inhibit/disrupt chemical reactions of bacteria
-Others stop DNA/protein synthesis
-Damage liver, kidneys, bone marrow - Broad Spectrum
- Kills many kinds of bacteria
- Narrow Spectrum
- Kills specific kinds of bacteria
- Culture and Sensitivity Testing
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-Lab procedure done before antibiotic is chosen
-Test to grow microbe - Viruses (1)
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-Not cells
-Consist of DNA/RNA
-Surrounded by protein shell
-No cytoplasms, enzymes, cell membrane
-Can only reproduce within host
-Causes initial infection, lay dormant, reappear months/years later
Ex. chicken pox to shingles - Viruses (2)
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-Identified by protein shell
-Some are self-limiting
-Severity depends on amount of cells affected
-Intracellular parasite
-100's from 1 host
-Some passed through placenta to unborn child
-Few known to be tumors - Antiviral Medications (Treatment Difficult Due To)
-
-Viruses are active only within cells
-Simple structure - not normal cell
-Use host cells - DNA/enzymes for cell replication
Kills virus, kills DNA of host cell - Zidovudine (AZT)
- AIDS - controls - $1,000's/month
- Acyclovir
- Herpes
- Saprophytes
- Live on dead, organic material - decompose - recycle chemicals
- Pathogenic saprophytes
- Cause infection on skin, throughout body
- candida Albicans
- Resident flora of skin
- Pneumocystic Carinii
- Pneumonia seen in AIDS victims, not normal system
- Coccus
- Round shaped cells
- Bacillus
- Rod-shaped cells
- Spirillum
- Coiled shells
- Strepto
- Chains
- Staphylo
- Clusters
- Vector
- Carrier
- What is bacteria?
-
Simple celled micro organism that is found everywhere.