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39 Cards in this Set
- Front
- Back
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Microorganisms that invade and multiply in body tissues and cause cellular injury
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INFECTION
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Microorganisms capable of causing disease
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Pathogens
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Nonpathogenic organisms that are prevalent on and in the body
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Normal Flora
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What is the purpose of normal flora?
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They prevent more harmful microorganisms from colonizing (taking up residence and growing) and multiplying within the body.
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How do normal flora accomplish their main goals?
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By occupying receptor sites on cells, monopolizing the nutrients, and secreting substances that are toxic to other microorganisms.
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Endotoxins are responsible for the symptoms seen in what illnesses?
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Botulism, tetanus, diphtheria, and E. coli (Escherichia coli)
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Bacteria are classified according to their?
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Need for oxygen, their shape, and their Gram-staining properties.
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Bacteria that RETAIN the stain used
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Gram-positive bacteria
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Bacteria that LOSE the stain
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Gram-negative bacteria (take up counter-stain)
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Classification of bacteria- 3 main groups
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Cocci (round)
Bacilli (rod shaped) Spirochetes (spiral) Though some grow in chains (streptococci); pairs (diplococci); and clusters (staphylococci) |
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What is an antibiotic?
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It is a chemical substance that can kill or alter the growth of bacterial microorganisms.
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What are the four most common multidrug-resistant organisms?
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1.) MRSA- Methicillin-resistant Staphylococcus aureus
2.) VRE- Vancomycin-resistant Enterococcus 3.) ESBL- Extended-spectrum beta-lactamase-producing pneumonia (Klebsiella pneumoniae or E. coli) 4.) C. diff- Clostridium difficile Another is penicillin-resistant Streptococcus pneumoniae |
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List microorganisms that can cause infection in humans
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Bacteria, prions, viruses, protozoa, fungi, rickettsia, helminths
others: mycoplasmas, Chlamydia |
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Protein particles that lack nucleic acids and are not -Inactivated by usual procedures for destroying viruses
-Do not trigger an immune response -Cause degenerative neurologic disease, such as variant Creutzfeldt-Jakob disease (mad cow disease) |
Prions
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Extremely small; seen only with an electron microscope
-Composed of particles of nucleic acids, either DNA or RNA, with a protein coat -Grow and replicate only within a living cell; survival and replication depend on host tissue |
Virus
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One-celled microscopic organisms belonging to the animal kingdom
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Protozoa
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Examples of pathogenic protozoa:
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-Plasmodium species: causes malaria
-Entamoeba histolytica: causes amebic dysentery -Other strains capable of causing diarrhea |
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-Small round or rod-shaped organisms
-Transmitted by the bites of fleas, lice, mites, and ticks -Can multiply only in host cells -Causes Rocky Mountain spotted fever and typhus |
Rickettsia
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-Tiny primitive organisms of the plant kingdom that contain no chlorophyll
-Include yeast and mold -Feed off living animals and decaying organic matter -Reproduce by use of spores -Cause candidiasis and tinea pedis (athlete’s foot) |
Fungi (that's not so fun) :)
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-Parasitic worms or flukes
-Belong to the animal kingdom -Pinworms, which mostly affect children, and roundworms and tapeworms |
Helminths
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What is the process of infection? {The infection chain (6)}
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Causative agent- link 1
Reservoir- link 2 Portal of exit- link 3 Mode of transfer- link 4 Portal of entry- link 5 Susceptible host- link 6 |
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What are some characteristics that affect virulence?
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The ability to:
Adhere to mucosal surfaces, skin, or cell walls Penetrate mucous membranes Multiply once in the body Secrete harmful enzymes or toxins Resist phagocytosis (destruction by WBCs) Bind with iron (essential to bacterial growth) |
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What are the four stages of the infection process?
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Incubation, prodrome (early stages of illness), illness, and convalescence (recovering, getting well)
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____________ and _____________ are methods used in the process of destroying all microorganisms, pathogens, or pathogenic products.
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Disinfection and sterilization
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The most effective means for destroying viruses and all other kinds of microorganisms is to....
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Expose them to high heat for a specific amount of time.
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Temp and time for using a steam sterilizer?
For dry sterilization? |
-250 degrees F for 20 to 30 mins
-320 degrees F for 90 mins to 3 hours |
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Reservoirs are?
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Places where microorganisms are found.
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What can be considered a reservoir?
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Infected wounds, human or animal waste, animals and insects, contaminated food or water, or a person with an infection.
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What is the portal of exit?
List some examples. |
It the route by which a pathogen leaves its host.
The gastrointestinal tract (feces), respiratory tract (coughing, sneezing), skin and mucous membranes (open or draining wound). |
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How can the portal of exit chain be broken?
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It can be interrupted by identifying and treating infected patients. Isolation techniques and barrier precautions that include the proper handling and disposal of secretions, urine, and feces, and exudate (fluid in or on tissue surfaces that has escaped from blood vessels in response to inflammation and that contains protein and cellular debris) can prevent pathogen transfer.
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What do the modes of transfer of pathogens include?
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-Direct personal contact with body excretions or drainage from an ulcer, infected wound, or a boil
-Indirect contact with contaminated inanimate objects (fomites), such as needles, eating utensils, dressings, or hospital equipment -Vectors, such as mosquitoes, fleas, or ticks that harbor infectious agents and transmit through bites and stings -Droplet infection, or contamination by the aerosol route through sneezing and coughing -Spread of infection from one body part to another |
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How can the mode of transfer link be broken?
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Can be interrupted by effective hand washing, proper disinfection and sterilization of medical equipment, use of aseptic technique in performing procedures and diagnostic tests, and use of Standard Precautions to prevent contamination.
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Where are the portals of entry?
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These include the mucous membranes of the eyes, nose, mouth, trachea, or skin. Consuming contaminated food and water with disease-causing microorganisms is a good way to get sick. Breathing in droplets of a sick persons cough or sneeze is another way.
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What are some ways to break the chain of the portal of entry?
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Using only sterile and clean items when caring for patients reduces the entry of pathogens. Barrier precautions (gloves, mask, condoms), safe handling of food and water, good personal hygiene, avoiding high risk behaviors, and protection from those pesky insects!!
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What makes a human host susceptible?
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Virtue of age, state of health, or broken skin.
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What are some ways to break the chain or lessen your chance of being a good host for infectious agents?
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Learn good health and hygiene habits, and immunizations. You can also be protected by using aseptic techniques, barrier precautions, and protective isolation. Proper nutrition and healthy lifestyles also couldn't hurt.
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What are the factors that place a elderly person at higher risk of infection?
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-Poor nutrition
-Inadequate hygiene -Impaired mobility -Chronic illness -Physiologic changes |
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What serves as the first line of defense against harmful environmental agents?
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-Intact skin
-Sebaceous glands excrete sweat, lactic acid, and fatty acids to limit microbial growth -Secretions from the mucous membranes lining the respiratory, gastrointestinal, and reproductive tracts contain an abundance of the enzyme lysozome. This is also found in tears and saliva. -Cilia (respiratory tract) trap microorganisms and debris (dead tissue or foreign matter) and propel them up and out of the body -Bones protect vital organs from trauma -Bone marrow produces defensive blood cells -The liver (Kupffer cells) destroy bacteria and also detoxifies harmful chemicals -Gastric secretions (hydrochloric acid) destroy ingested pathogens -Feces flushes bacteria from intestines and urine flushes the urinary system |
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What is the body's second line of defense?
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Mechanisms of fever, leukocytosis, phagocytosis, inflammation, and the action of interferon (biologic response modifier that affects cellular growth).
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