microbiology
TRANSCRIPT
DISEASE
Causes of Disease
MICROORGANISM
Indirect
Pathogenic
Nonpathogenic or Commensals
Direct
1. BACTERIA
A. COCCI
1. STREPTOCOCCI
2. STAPHYLOCOCCI (PYOGENIC)
3. DIPLOCOCCI
B. BACILLI
C. SPIROCHETE
2. FUNGI
3. RICKETTSIAE
4. PROTOZOA
6. HELMINTHS
7. VIRUSES
5. MYCOPLASMA
TYPES OF ASEPSISTYPES OF ASEPSIS
MEDICAL
SURGICAL -- it is said to have no living organism in or on the object
TYPES OF STERILIZATION
-- prevents spread of disease from one person to another.
A. BOILING
B. GAS AUTOCLAVE
C. STEAM AUTOCLAVE
D. CHEMICAL DISINFECTANTS
E. HEAT
F. IONIZING RADIATION
What nursing measure is considered the most important way to prevent the spread of infection? HandwashingHandwashing
TRANSMISSION OF INFECTION
Reservoir -- any environment that an organism can survive and reproduce
-- Fomite -- inanimate objects
1. Carrier
2. Healthy carrier
3. Convalescent carrier
4. Incubatory carrier
When are you the most contagious? Why?
Portal of Exit
--Vector-- an insect or animal that transfers an infectious agent from one host to another
Portal of Entry
-- Most infectious agent are restricted to only one portal of entry
Mode of Transmission
1. Direct contact
2. Indirect contact
3. Droplet
4. Vectors
Susceptibility of the Host-- age
-- nutrition
-- presence of other diseases
-- host’s immune system
Resistance to infection
-- influenced by:-- age
-- state of nutrition
-- hormones
-- adequate blood supply to infected area
-- location of the infection
-- effective immune system
VIRULENCE -- how powerful the organism is to produce disease
CHAIN OF INFECTION
Body’s Defense Mechanism
1. Skin and Mucus MembranesUnbroken skin – first line of defense
-- skin is acidic-- normal flora
Mucus membranes-- normal flora-- cilia
2. Lysozymes and Gastric Juices Lysozymes – present in tears, saliva,
mucus, skin and some internal body fluids
Gastric juices are strongly acidic
3. 3. Natural ReflexesNatural Reflexes
-- Sneezing, coughing, vomiting, and diarrhea
4. Interferon-- protein produced by WBC’s in
response to viral infection
-- triggers infected cells to produce anti-viral protein
-- inhibits cell reproduction
5. Reticuloendothelial System-- provides humoral immunity
(antibodies)IgG IgA IgM IgD IgE
-- cellular immune response (T- lymphocytes)--Phagocytosis -- fever
Nonspecific Immune Response
Signs & Symptoms – heat, redness, swelling & occasionally painFunction:
1. Contain & localize infection
2. Bring nutrients for tissue repair 3. Destroy microorganisms 4. Remove debris
1. VASCULAR RESPONSE a. Vasoconstriction followed by vasodilation b. Release of Histamine c. Heat and redness now apparent2. FLUID EXUDATE a. H2O, protein, glucose, electrolytes move into interstitial spaces. b. Causes swelling & pain c. Function 1. Brings more nutrients to site for healing 2. Dilutes bacterial toxins 3. Transports cells needed for phagocytosis3. CELLULAR EXUDATE ---White blood cells move into area to kill any microorganisms & to remove debris.----Either healing occurs or if inflammatory
response is not successful, the infection spreads
Nonspecific defense First-line barriers
Skin & mucous membranes
Fluids Chemicals
Nonspecific defenseSecond-line barriersChemical actioncomplement &interferon
Phagocytosis Inflammation
Specific defenseLymphocytes & macrophages
Cell-mediated immunity
Antibody-mediated immunity
Complements -- a group of proteins in the blood that influence the inflammatory process & serve as mediator in the antigen-antibody reaction
Invasion by Invasion by PathogensPathogens
What is the difference between and infection and an inflammation?
-- Infection – invasion of the body by a microorganism
-- Inflammation – the body’s response to an invasion or trauma
Three things happen when an organism enters the body:
1. Body will eliminate the pathogen
2. The pathogen will reside without disease
3. The pathogen will cause an infectious disease
Identification of OrganismsIdentification of Organisms
Skin Test – Patch Test – Interdermal Test
--Material injected intradermally & reaction is read in 48 to 72 hours
-- Positive reaction means organism has entered the body, but does not mean you are actively infected.
-- Done for Histoplasmosis, mumps, diphtheria, tuberculosis
CBC, WBC, and Differential Count
ESR (erythrocyte sedimentation rate or Sed rate) -- indicates inflammatory process
Immunologic Tests
-- Agglutination (clumping) Certain bacteria added to a
patient’s serum will cause clumping due to the presence of antibodies
--Precipitation TestsA solution of antigens and
antibodies in the right concentration will cause a white line to appear in the test tube
Indicates patient has antibodies to a particular antigen.
Used to detect antibodies to tetanus, diphtheria, & Scarlet Fever
Criminology labs use it to know if a particular blood stain is from an animal or a human
-- ImmunofluorescenceDye is attached to an
antibody & when the antibody-antigen reaction occurs, it will show up under an ultraviolet microscope
Used to detect syphilis & streptococcus
-- Tissue Biopsy Viruses can only be studied by
growing them in living tissue
--DrainageDirect Examination
Coagulase Test
-- Test to see if an enzyme produced by a bacteria produces a thrombus
-- If positive, organism is considered more virulent
--CulturesPlacing a small amount of a
specimen on a special growth medium
-- Acid FastDye applied to smear on slideIf color remains, organism is
considered Acid Fast.
leprosy
tuberculosis
--Gram StainStaining process involves 4 steps
using Crystal Violet, Gram’s Iodine solution, Alcohol, & Safranin
Gram negative if stained redanthrax
Gram positive if retain purple stain
staphylococcus
Gram-Positive Bacteria
Clostridium difficile Pseudomenbranous colitis
Staphylococcus aureus Pneumonia, toxic shock, cellulitis, boils, post-op peritonitis
Staphylococcus epidermis IV line-related phlebitis, post-op bone & joint infections
Streptococcus pneumoniae Pneumonia, meningitis, otitis media, sinusitis, septicemia
Steptococcus pyogenes Scarlet fever, impetigo, rheumatic fever
Steptococcus viridans Endocarditis
Gram-Negative Bacteria
Campylobacter jejuni Diarrhea (worldwide cause)
Escherichia coli Urinary tract, pylonephritis, septicemia, gastroenteritis, peritonitis
Haemophilus influenzae Pneumonia, meningitis
Klebsiella pneumoniae Pneumonia
Legionella pneumophilia Legionnaire’s Disease
Neisseria gonorrhoeae Gonorrhea
Neisseria Meningococcus Meningitis (most common cause)
Pseudomonas aeruginosa Wound, urinary tract, pneumonia, IV line infections
Salmonella enteritidis Gastroenteritis, food poisoning
Salmonella typhi Typhoid fever
Communities prevent the outbreak of disease by:
1. Isolation
2. Quarantine
3. Setting standards
4. Vector control
5. Giving authority to Occupational Safety & Health Administration (OSHA) & Washington Industrial Safety and Health Act (WISHA)
What cells in the bone marrow are capable of producing many different types of blood cells? Stem Cells
How are allergies and immunity similar?
Both result in antibody formation
Cells are involved with the immune response?
B Lymphocytes T Lymphocytes
Macrophages Neutrophils
TYPES OF IMMUNITY
1. Natural (Actively-Acquired Immunity)
a. Immunity to a specific microorganism due to having had the disease
b. Gives life-long immunity for that particular microorganism as Memory Cells are produced
c. Examples: Measles, Mumps, Chickenpox
2. Artificially Acquired Immunity
a. Killed or attenuated (weakened) antigen tricks the body into producing antibodies
b. Believed to provide life-time immunity as Memory Cells are also produced
c. Examples: Measles, Mumps, Chickenpox, Pertussis
3. Passive Immunity
a. Uses antibodies produced by another organism – human or animal
b. Immunity is temporaryc. No memory cells are produced
d. Types:1. Artificially-Acquired Passive Immunity
a. Antitoxin
1. A substance formed after exposure to a Toxin in same way the body produces antibodies
2. Examples: Tetanus, Antivenom, botulism
b. Gamma Globulin (Immune Globulin)
1. Human immune serum used for exposure to Hepatitis A
2. No Antigen is used, so no Memory Cell is produced
2. Naturally-Acquired Passive Immunity
--- Antibodies received by the Newborn from it’s mother
Any time a nurse gives a patient an immunizing agent against a specific disease, what does he/she need to be concerned about?
Called?
-- Severe allergic reactions can develop in some sensitive individuals
Anaphylaxis
TERMINOLOGYTERMINOLOGY
Disinfection
-- Attempt to kill pathogenic microorganism either through physical or chemical means applied directly
Disinfestation
--Destruction of insects, rodents, or other animal forms, which may transmit disease.
Endemic -- a disease of low morbidity that is constantly present in a human community, but clinically recognizable in only a few
Pierce County
Epidemic -- a disease attacking many people in a region at the same time
Pandemic -- worldwide epidemic disease
Incident --number of new cases of a specific disease occurring during a certain period
Incubation period
--the time required for the development of the disease
November 2005October 2005
30 new cases
8 new cases
Prevalence
--total number of cases of a specific disease in a given population at a certain time. West Nile Virus – Washington
State (2005)
WNV-Positive Humans: 0
WNV-Positive Horses: 1
WNV-Positive Birds: 1
WNV-Positive Mosquito Pools: 2
In State Acquired Cases
Suspect -- questionable, debatable origin of a disease
Gaetan Dugas
Bactericidal
Bacteriostatic
-- able to kill bacteria
-- arresting the growth or multiplication of bacteria
Drainage
1. Sanguineous
2. 2. SerosanguineousSerosanguineous
3. Serous
4. Purulent
-- bright red: indicates active bleeding
-- pale, red, watery: mixture of serous and sanguineous
-- clear, watery plasma
-- thick, yellow, green, tan, or brown
INFECTIONS
AcuteChronicPrimarySecondaryLocalGeneralized Systemic
FocalLatentSpecificMixed
-- the use of appropriate barrier when anticipating contact wit blood or other body fluids of any patient
STANDARD (UNIVERSAL) PRECAUTIONS
Reasons for the increase in infectious diseases: more susceptible people neglect in getting immunizations Increase in resistant microorganisms Increase in the number of pre-schools and
day care children Not all states require that all students
receive certain vaccinations Increase in number of ill or susceptible
people entering into the country
TYPES OF ISOLATION
Disease-specific isolations-- to prevent the spread of a particular
disease
Category Isolation
A. Strict Isolation
1. Most restrictive
2. Highly contagious diseases
3. Chickenpox; diphtheria; viral hemorrhagic fevers; varicella zoster (shingles)
B . Contact Isolation
1. Pathogens can be spread by touching
2. Wound infections with virulent or multiple drug resistant; rabies; scabies
Itch mite
MRSA
C. Respiratory Isolation
1. Transmitted by droplet or airborne
2. Measles; meningitis; mumps; drug resistant TB; Severe Acute Respiratory Syndrome (SARS)
D. Enteric Precautions
1. Transmitted by anal-oral route2. Hepatitis A
E. AFB Isolation
1. Acid-Fast bacillus
2. Tuberculosis (requires room with special ventilation)
Reverse or Protective Isolation
A. Prevents Infection in highly susceptible persons
B. CDC recommends conscientious medical asepsis; such as HANDWASHING
Role of Infectious Control Nurse
A. Detection of Nosocomial infection
C. Reporting
B. Recording
-- Most common nosocomial infections
1. Staphylococcus aureus
2. Pseudomonas aeruginosa
3. Escherichia coli
-- Infection control committee
-- Pierce County Health Department
-- State Health Department in Olympia
-- CDC – Atlanta Georgia-- Surgeon General’s Office
-- WHO
http://www.cdc.gov/ncidod/dhqp/pdf/guidelines/Isolation2007.pdf
Guideline for Isolation Precautions Preventing Transmission of Infectious Agents in
Healthcare Settings 2007