Chapter 17 Flashcards
What is a micro-organism?
Microscopic organism that can grow in or on a host organism and cause disease
What is an infection?
Establishment and growth of microorganisms on or in host
What happens when an infection causes injury to host?
Disease
What microorganisms cause disease?
Pathogenic Microorganisms
What do Pathogenic Microorganisms do?
Cause obstruction by multipying in large numbers
Cause tissue damage
Secrete organic substances called exotoxins
Side effects of exotoxins:
high body temp, nausea, vomitting, shock
What are the four infection agents?
Bacteria
Viruses
Fungi
Protozoan
Characteristics of Bacteria and how are they classifed?
Microscopic, single cell, simple organization
Prokaryotes (lacks nucleus)
Classified by morphology, biochemistry, and genetic constituion
What are Endospores?
Highly resisitant form of bacteria in resting state
Common bacterias:
Streptococcal Pharyngitis (strep throat)
Klebsiella Pneumoniae (Pneumonia)
Clostridium Botulinum (Botulism - food poisioning)
Characteristics of Viruses and how are they classified?
Simpler in form compared to bacteria or animal cells
Neither prokaryotic nor eukaryotic - conisdered obligate intracellular parasites
Cannot live outside a living cell, it needs a host
Classified by its nucleic acid, size and symmetry
What is a Virion?
Viral particle that attaches to a host and inserts genetic info
Why does herpes simplex just appear now and then?
Latent or dormant infection: travels in nervous system and reappears sporadically
Common viruses:
Epstein-Barr (Mono)
Papillomavirous (HPV)
Rhinovirus (Common cold)
Characteristics of Fungi
Eukaryotic organism with membrane-bound organelles
Larger than bacteria
Can be dimorphic - grow into 2 distinct forms
What are the two forms Fungi can grow into?
Filamentous hypha - mold
Yeast
How does Fungi look under microscope?
Similar to a tree or plant
Diseases caused by Fungi
Superficial - discoloration of skin - example: Tinea nigra - black/brown on palm/planter
Cutaneous infection - keratinized tissue - Example: Tinea pedis (Athlete’s Foot) or Ringworm
Subcutaneous fungal infections via skin trauma
Systemic, via circulatory or lymphatic system; may be fatal
Characteristics of Protozoa
Unicellular, neither plant nor animal
No cell wall, greater size than bacteria
Motile and Eukaryotic
Can ingest food particles and some have Rudimentary - basic digestive systems
Classifed by Motility
Can form cysts which can help them survive while out of the host
Typical protozoan infections:
Trichomonas vaginalis
Plasmodium Vivax - malaria
6 steps of establishment of disease:
- Encounter
- Entry
- Spread
- Multipy
- Damage
- Outcome
Microorganisms that can pass through the placenta are:
Congenital infections
Two types of congential infections:
Rubella
Syphilis
When are we exposed to infectious microorganisms?
Birth
Some encounters we get rid of, others become:
Colonizers
What systems are in direct contact with external environment?
Digestive
Billiary
Urinary
Respiratory
Peritoneal cavity - women
Two ways to acqiure infections by entry to the body:
Ingression - does not involve deep tissue penetration
Penetration - skin layer broke by microorganism
Common Ingression and symptoms:
Ingested food & water
Inhale aerosols/dust
diarrhea and pneumonia
Types of microbes that penetrate:
Vectors - ticks, fleas, mosquitos
Phaygocytes
What is a phaygocyte?
Engulfs foreign microbes and transports it deeper
More important barrier to overcome is hosts:
immune system
What determines the degree of spread?
Where the microbe enters and where it ends up
The time that the microorganism takes before it multiplies is the:
Incubation period
Damage to cells can be:
Direct or Indirect
What is direct damage?
Cell death caused by destruction of the host cell
Toxins and posion secreted by infectious agent
What is indirect damage to a host?
Metabolism is altered
Death can result if a person has ingested toxins by the organism that causes:
Botulism
3 outcomes of infection:
Host controls the infection
The infectious agent overcomes the host’s immunities to cause disease
The host and infectious agent compromise and live in somewhat anxious state of symbiosis (they live together)
For infections to be transmitted, the following must exist:
Host
Infectious microorganism
Mode of transportation
What is a host?
Human
What are the modes of transportation?
Exogenously or endogenously
What is exogenously?
Microorganism transmitted outside of the body (can be indirect or direct)
What is direct transportation?
When infected individuals transmit infection by holding hands, coughing, sexual contact, etc
What is the common type of infection that may be spread by direct contact?
Staphylococcal Aureus (impetigo)
Liquid mediums of direct transportation:
Phlegm, aerosols, sneezing, coughing, excretions (urine and feces)
What are ways of indirect spreading?
Vectors (carriers) transfer infectious agent from one host to another
Formites
What are formites?
Type of indirect spreading through inanimate objects - food, water, radigraphic equipment, gloves
What is endogenously?
Encounter organisms already present in or on the body
Staphylococci on surface of skin can invade deeper through laceration
What is the reservoir?
Site where infectious organism camps out
The person who carries the infection is called:
Host/reservoir
What are nosocomial infections?
Hopsital acquired infections
What percent of hospital patient’s acquire some additional condition being in the hosptial?
5%
How many deaths annually in US for nosocomial?
100000+/year
8th leading cause of death
What is Iatrogenic?
Infection as a result of intervention with physician
example - develop pneumonia from lung biopsy
What makes a patient more likely to pick up disease?
Compromised immune system
What is patient flora?
Relationship between host and microbe is beneficial or neutral, until compromised
What are 2 blood born pathogens that are of concern for nosocomial?
HBV and HIV
How is HBV spread?
Accidental needle sticks
How does HIV infect the system?
Infects the immune systems T4 cells; as a result the virus renders these blood cells to be less effective in preventing disease
What does AIDS stand for?
Acquired Immunodeficiency Syndrome
What part of the hosptial environment causes nosocomial?
Fluids, food, air, medications, dust
What are 2 invasive procedures that cause nosocomial?
Foley catheter
ET tubes
What is the most common nosocomial infection?
UTI
How is the skin a mechanical and chemical defense?
Mechanical: shedding skin cells (rubbing hands together)
Chemical: sweating
What is the chemical mechanism in respiratory, genitourinary, GI, and the conjuctive of the eye?
Mucous
Why is the enzyme in tears and urine that destorys bacteria?
Lysosomes
What is Phaygocytosis?
Phagocyte removes foreign particles by engulfing and destorying them
What is normal body flora?
Microbial community found in or on a healthy person
What is Chemotherapy?
To kill a microbe within the host requires a selective toxicity of a drug
What are the 2 kinds of chemo drugs?
Static and Cidal
What do static drugs do? Example?
Inhibit growth
Ex - Tetracyclines
What do Cidal drugs to?
Kill or destory
Ex - Penicillin
What do vaccines do?
Induce active immunity in the body by making the body produce an antibody
What is WHO?
World Health Organization - issues recommendations for infection control
Who controls the infection environment in the US?
US dept of Health and Human Services
Center for Disease Control and Prevention
Who enforces the Center for Disease Control and Prevention?
OSHA
What is Asepsis?
Freedom from infection
What are the 2 methods of asepsis?
Surgical and medical
How to prevent infection in surgery?
Sterilization
What is sterilization?
Killing of all life forms. Probability of infection is zero
What are disinfectants?
Chemicals that alter the environment available to the microbe
If a disinfectant is a topical than it is:
an antiseptic
What are the two agent types of disinfectants?
Bacteriostatic agent
Bacteriocidal agent
Common chemical disinfectants?
Chlorine
Iodine
Hydrogen Peroxide
Ammonium on surfaces
Ethylene oxide - sterilization
What percent of hydrogen peroxide is used in deep wounds?
3%
What is the most frequently used method for sterilization?
Heat
What type of heat is preffered for sterilization and what device?
Moist heat using an autoclave
Why is moist heat better for sterilization?
Carries heat better, greater surface area
What is pasteurization?
Moderate heat - followed by rapid cooling
How many nm of UV light to maximize killing microbes?
260nm
What is the single most important way to prevent infection?
Handwashing
What kind of soap is used for handwashing?
Bactericidal
How long would it take for soap to kill all bacteria?
7-8 minutes
Under the nail area is:
Subungual
8 steps to handwashing:
- Approch the sink - use foot and knee pedals
- Wet hands - keep below elbows
- Apply soap - liquid form
- Being at wrist, work towards fingertips
- Rinse and allow water to run down over hands
- Repeat the process to cleanse from elbow to fingertips
- Turn off water - use towel on handles
- Dry from eblow to fingertips
Standard precautions when coming in contact with body fluids:
Hand washing
Gloving
PPE
Needle recapping
Bio spills
How to recap needles:
one-handed scoop method - place in sharps container
How many needle sticks happen per year?
800,000
How to handle bio spills?
Bleach solution - discard paper towel in designated medical waste container
What are 3 types of transmission based precautions?
Airborne precautions
Droplet precautions
Contact precautions
What are airborne precautions? And what are the infections you can get?
Pt wears mask when leaves the room
Negative pressure isolation room w/door closed. Healthcare worker should wear respiratory protection that filters inspired air
TB, chicken pox, measels
What are droplet precautions? And what are the infections you can get?
Wear a surgical mask when within 3 ft of patient
Rubella, mumps, influenza
What are contact precautions? And what are the infections you can get?
Remove gloves before leaving room
Clean equipment
MRSA, impetigo, hepatitis A, C-diff
What is MRSA?
Methicillin Resistant Staphylococcus Aureus
Virulent pathogen that spreads through contact
Sometimes called
“super bug”
Contact precaution technique
- Determine the number of cassettes needed - place into plastic bags
- Move machine into isolation room
- Locate the isolation supplies
- Remove all ornamentation
- Put on lead apron
- Wash hands
- Put on gown - grab from arm holes
- Put on mask, cap, googles
- Put on gloves
- Have assistant put on gown, gloves, cap
- Enter isolated area and introduce yourself
- Position the patient
- Assistant will make the exposure
- Remove cassette - never touching the inside. Assistant never touching outside
- Untie the waist strings of the gown
- Untie the neck strings and pull down so the sleeves are inside out
- Remove gloves.
- Remove the cap and the mask
- Wash hands
- Have assistance follow same protocol. Clean equipment
- Wash your hands
How to dispose of toxic waste?
Use leak proof bags that are colored differently (usually red)
How should needle containers be handled according to OSHA:
Properly labeled
Properly sealed and covered
Handled only by trained and protected personnel
How do chemicals in healthcare reach target organs?
Absorbed, transported, and metabolized in the body
Another name for Bio-Hazardous Waste
Infectious Waste
What are examples of Bio-hazardous waste?
Blood, body fluids, and tissues
Who collects bio-hazardous waste?
Licensed bio-hazardous waste hauler
What is medical waste?
Waste that is generated in labs and clinical settings. Not contaminated but could appear hazardous.
What are examples of medical waste?
Non-contaminated syringes (no needles)
Empty specimen bottles
Bandages with blood
What are commercial cleaning products?
Sterilants, disinfectants, pesticides
MSDS sheet must include:
Physical and chemical characteristics
Potential hazardous effects
Recommendation for appropriate proptective measures
Recommendation for disposal
Protozoa motility classifications:
Amoeboid locomotion - wavelike
Flagella - long tail
Cilia - short protein tail