Download How Microbes cause Disease?

The Infectious Process,
Surgical Site Infection, &
Environmental Controls
ST220:
Concorde Career College
Infectious Process
Objectives
• Define the terms related to disease
and infection and outline the
infectious process.
• Define the term pathogenesis.
Infectious Process
Disease Terminology
• Disease – Abnormal state in which all
or part of the body does not function
correctly.
• Pathophysiology – Study of disease
that emphasizes the relationship of
the pathologic and physiologic
aspects of the disease and the
fundamentals of treatment.
Infectious Process
Disease Terminology (continued)
• Etiology – Cause or origin of the
disease
• Idiopathic – Self-originating/without
known cause
• Incidence – Range of occurrence and
tendency to affect certain groups
(e.g., gender, geographical location)
Infectious Process
Disease Terminology (continued)
Disease classification based on severity
and duration
1. Acute – Severe but usually short
lasting
2. Chronic – Less severe but long
lasting or recurring
3. Subacute – Less severe than acute
and/or not as long lasting as chronic
Infectious Process
Disease Terminology (continued)
Communicable – can be transmitted
from one individual to another
Epidemic – affects many people in the
same region at the same time
Endemic – continuously affects some
people in a particular region
Pandemic – prevalent throughout an
entire country, continent, or the world
Infectious Process
Disease Terminology (continued)
• Nosocomial infection
• Community acquired infection
• Surgical site infection (SSI)
Infectious Process
Direct causes of disease:
•
•
•
•
•
•
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Disease producing organisms
Malnutrition
Physical agents
Chemicals
Birth defects
Degenerative processes
Neoplasms
Infectious Process
Predisposing causes of disease:
• Age
• Gender
• Heredity
• Life situations/habits
• Occupation
• Exposure to the elements
• Preexisting comorbid conditions
• Psychogenic influences
Infectious Process
Diagnosis of Disease
Diagnosis – Conclusion as to the nature
of the disease
 Symptoms – Conditions noted by the
patient (subjective)
 Signs – Conditions noted by the
healthcare provider (objective)
 Tests – Factual information concerning
the patient (e.g., laboratory studies,
diagnostic imaging)
Infectious Process
Disease Terminology (continued)
• Syndrome – A group of signs and
symptoms that accompany a
particular disease
• Prognosis – Prediction of the
probable outcome of the disease
(based on the condition of the patient
and the expected course of the
disease)
Infectious Process
Disease Treatment (Therapy)
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Surgery
Radiation
Chemotherapy
Rehabilitation (Physical, Occupational,
Speech, Substance Abuse)
 Alternative (Herbs, Acupuncture,
Healing Touch, etc.)
 Prevention (Prophylaxis)
Infectious Process
Infectious Process
Sources of infectious disease
(contamination)
Environmental
Fomites
Air
Vectors
Human
Hair, Skin, Subungual areas
Blood and body fluids
Human error
Infectious Process
Infectious Process
Modes (routes) of transmission
(contamination)
Airborne (including droplet
contamination)
Contact (direct and indirect)
Common vehicle (infection carried in
blood)
Vector
Infectious Process
Infectious Process
Portal of entry and exit
Skin (intact or traumatized)
Respiratory tract
Digestive tract
Urinary tract
Reproductive system
Infectious Process
Infectious Process
Public Health Considerations (disease
prevention)
Disposal of sewage and garbage
Water purification
Prevention of food contamination
Pasteurization
Infectious Process
Infectious Process
Healthcare (disease prevention)
Antisepsis
Handwashing
Disinfection
Sterilization
Infectious Process
Pathogenesis
Development of a disease due to a
pathologic, physiologic, biochemical,
or biomechanical mechanism.
Infectious Process
Objectives
• Understand the immunologic defense
mechanism and provide examples of
the different types of immunity.
• Understand the allergic reaction and
provides examples of the different
types of allergic responses.
Infectious Process
Immune System
• Provides the body with protection
against harmful agents
Consists of
Certain blood cells
Lymphatic system
Infectious Process
Immune System
• Nonspecific defenses – effective
against any harmful agent
• Specific defenses – effective against
a certain agent and no other
Infectious Process
Occurrence of Infection
• Exposure to a pathogen
• Pathogen enters the body
• Virulence – power of the organism to
overcome the defenses of the host
• Ability of the organism to produce toxins
• Dose – Number of pathogens that
invade the body
• Predisposition of the individual to
infection
Infectious Process
Nonspecific Defenses
• Skin – Mechanical barrier (often
referred to as the “first line of
defense”)
• Mucous Membranes – Mechanical
barrier, secretions trap foreign
material, cilia move impurities out of
the body
Infectious Process
Nonspecific Defenses (continued)
Body Secretions (tears, sweat, saliva,
digestive juices)
Wash away organisms
May contain acids, enzymes, or
chemicals to destroy invaders
Reflexes (coughing, sneezing)
Remove foreign matter
Vomiting and Diarrhea
Expel organisms and toxins
Infectious Process
Nonspecific Defenses (continued)
• Phagocytosis – White blood cells
primarily neutrophils and
macrophages take in and destroy
waste and foreign material
• Natural Killer Cells – Type of
lymphocyte that recognized abnormal
cells and destroys them
Infectious Process
Nonspecific Defenses (continued)
Inflammation – The body’s protective
response to injury (includes friction,
thermal injury, chemical exposure,
cuts, or blunt force)
When injury occurs, the injured tissue
releases histamine from the damaged
cells. Histamine causes small blood
vessels in the area to dilate, increasing
blood flow to the area
Infectious Process
Nonspecific Defenses (continued)
Classic Local Signs of Inflammation
Pain (dolor)
Heat (calor)
Redness (rubor)
Swelling (tumor)
Loss of function (functio laesa)
Infectious Process
Nonspecific Defenses (continued)
 Classic Systemic Sign of Inflammation

Fever
 Phagocytes exposed to infecting
organisms release substances that act
to raise the body temperature
 Fever stimulates phagocytes, increases
metabolism, and decreases the ability of
certain organisms to multiply
Infectious Process
Nonspecific Defenses (continued)
• Interferon – Substance produced by
cells infected with viruses produce a
substance that “interferes” with
infection of other cells
Infectious Process
Specific Defenses
• Immunity – Power of an individual to
resist or overcome the effects of a
particular disease (often referred to as
the “final line of defense”)
Infectious Process
Specific Defenses
Inborn Immunity – Individual is born
with certain defenses
Species immunity – Meaning for
example that humans don’t “usually” get
animal diseases (e.g., distemper) and
animals don’t get measles
Racial immunity – Some racial groups
appear to be more immune to certain
diseases (e.g., polio)
Individual immunity - Inherited
Infectious Process
Specific Defenses
Acquired Immunity – Certain defenses
develop during an individual’s lifetime
Naturally acquired – Due to contraction and
survival of a specific disease (body
produces antibodies against the invading
agent)
Active – When host is directly involved in
production of antibodies (usually effective for
an extended period of time, possibly lifetime)
Passive – Passed from mother to fetus
through the placenta (may be effective for up
to 6 months)
Infectious Process
Specific Defenses
Acquired Immunity (continued)
Artificially acquired – Exposure
(purposeful) to an attenuated
(weakened) or biotechnologically
engineered (recombinant DNA
technology) agent
Immunization (active) - vaccination
Immunization (passive) - antiserum
Infectious Process
Specific Defenses
Immunization (passive) – antiserum (cont)
Gamma globulin (human) – Given to individuals exposed
to HAV, measles, etc. or with congenital immune
deficiencies
RhoGAM (human) – Prevents formation of Rh antibodies
by an Rh- mother or when transfusion incompatibilities
occur
Antivenin (human) – Snakebite sera
Rabies antiserum (human or horse) – To treat victims of
bites of rabid animals
Infectious Process
Disorders of the Immune System
Allergy – Hypersensitivity to various chemicals
Autoimmunity – Abnormal reaction to “self”
Immune Deficiency Diseases
AIDS
Cancer – Body does not recognize abnormal cells
as “nonself” and does not react
Immunotherapy – To reduce the risk of transplant
rejection
Transmission of
micro-organisms
Microorganisms may be transmitted
from an infected individual to a
susceptible person in the following
ways.
Contact with an infected person
i) Direct contact:
Handling, touching, coughing, sneezing & blood to
blood & secretion to secretion contact.
ii) Handling/touching
Boils caused by Staphylococcus infections.
Hospital acquired Staph. infections in new born
nurseries are one of the most dreaded instances
of touching contact.
iii) Coughing & sneezing
Viral infections & common cold spread by not
covering the mouth and & nose when coughing &
sneezing, allowing air droplets containing these
viruses to be inhaled by others.
Droplet infections spread by
coughing
Sneezing also produces droplets
Sneeze producing a mist of aerosol
Contact with an infected person
iv) Secretions to secretions contact
Sexual intercourse—transmits STDs such
as:
Gonorrhea, Syphilis, Genital warts, Herpes,
Chlamydia & HIV.
v) Blood to Blood contact
Blood transfusions, I.V. drug users,
sharing needles.
Hepatitis B, C. & HIV.
Sexual Contact
Indirect contact
Host or carrier has contaminated something (most
often food) with which a susceptible person later
comes in contact.
i) Handling articles
laundering of contaminated bedding of someone
with dysentery, salmonella, or hepatitis A.
ii) Touching contaminated substance
Poor personal hygiene.
iii) Eating food prepared by an infected person
Typhoid fever, diarrhea (E. coli)
Hepatitis A, dysentery, cholera.
House Fly: Carrier of deadly
disease causing germs.
Yaws
Cockroaches on food.
Contact with human carriers
A carrier is someone who harbors a
pathogen without suffering from the
disease.
Respiratory secretions given off while
coughing & sneezing (Diphtheria patient) &
human fecal matter (Typhoid patient)
A common bowel commensal E. Coli can
cause serious outbreaks of food poisoning.
Good hand washing technique must be
strictly adhered to by all, who work in
restaurants.
A River of Filth
Contact with animals or insect
carriers
Animals (cattle, domestic animals, wildlife,
horses & pigs) and
Insects (flies, mosquitoes, ticks & mites)
are capable of transmitting diseases to
humans.
People can get certain diseases from the
bite of or direct contact with an animal.
Eating meat & other products from a
diseased animal can also be a cause of
disease to humans.
Cattle
Domestic animals, like cats can
spread disease to humans
---and Dogs too
Even Horses !!
And surely pigs too
Where there is food there are flies
Mosquitoes transfer Malaria,
West Nile virus, Yellow fever,
and Dengue fever
Mosquito sucking blood
A Tick is being removed from the
skin where it is firmly attached.
Ticks
Mites infestation of the skin
Dust Mites, can predispose to
asthma
House Dust Mite
Bats can transmit Rabies
A mad dog, infected with Rabies
Racoon
An infected Coyote
Fomites
Fomites: are inanimate objects that
can carry pathogens & thus serve as
disease carriers.
Fomites can transfer microbes
Fomites
Improperly sterilized or handled
instruments
Improperly washed and cleaned
cutlery
Contact with inanimate or air
borne carriers
Air, dust, food, solid, water,
instruments, & fomites.
Microorganism invasion
The infectiveness of an invasion by
bacteria will depend upon:
The kind of organism & its virulence
Number of organisms
Resistance or body defenses
Location of the invasion
Portals of entry for
microorganisms
i) Respiratory tract:
Many diseases especially involving
respiratory system spread through droplet
infection.
This fine spray of mist is discharged by
sneezing & coughing. If this spray comes
from a patient with a cold, influenza, T.B.,
etc. another person may get the disease by
inhaling the droplets.
Portals of entry for
microorganisms
ii) Gastrointestinal tract:
contaminated or infected food & drink
can spread disease.
Organisms that live in intestines, will
be spread through contaminated food
objects
e.g. Typhoid fever, Dysentery,
Undulent fever, Cholera and
Food poisoning.
Food
Food
Portals of entry for
microorganisms
iii) Genitourinary Tract:
Bladder infections (cystitis) syphilis &
gonorrhea.
Observe precaution when working
with patients & body fluids.
Portals of entry for
microorganisms
iv) Abrasions in the skin:
Infection resulting from an un-sterilized cut in the
skin.
V) Insect bites also transmit microorganisms.
Mosquitoes—malaria & yellow fever
Tsetse fly —sleeping sickness
Flies: Typhoid, dysentery, cholera.
Animals —may transmit Rabies
Body lice —typhus fever
Fleas —bubonic plague.
Tse-Tse Fly
Sleeping Sickness
Body Lice
Crab (pubic) louse
Portal of exit for microorganisms
i)
ii)
iii)
iv)
v)
vi)
Saliva
Urine
Sputum
Feces
Blood
Nasal Discharge
Nasal discharge
Saliva
Urine
Sputum
Giardia lamblia in feces
Schistosoma mansoni egg in stools
Blood
Environmental Controls
Review terminology, Table 7-8,
ST4ST, pg. 140
How do these terms relate to the sterile
field within the OR?
Environmental Controls
Classification of Patient Care Items
Critical
Used for an invasive procedure; high risk of
disease transmission
Semi-critical
Come in contact with mucous membranes or
non-intact skin; lesser risk of disease
transmission
Non-critical
Come in contact with intact skin; least risk of
infection
Environmental Controls
AST: RSOPs
Decontamination of Instruments
Packaging Material and Preparing Items
for Sterilization
Monitoring Sterility
Environmental Controls
Disinfecting Principles and Agents
Cleaning
Disinfection
High-level Disinfection
Intermediate-level Disinfection
Low-level Disinfection
Sterilization
Environmental Controls
Compounds
Glutaraldehyde
Sodium Hypochlorite
Phenol (Carbolic Acid)
Quaternary Ammonium Compounds
Alcohol
Environmental Controls
Terminal Cleaning Vs.
Decontamination of the OR
What is the difference?
How often is the OR cleaned?
When does this take place?
Environmental Controls
How do these practices limit the
incidence of surgical site infection?