Infection Control

Basic Principals of Infection Control How disease is transmitted and the main

ways to prevent transmission. Microorganisms are small living organisms

invisible to the naked eye Two types of microorganisms 1. Pathogens 2. Nonpathogens

What are microorganisms?

Microorganisms are small living organisms invisible to the naked eye

There are five classes of microorganisms Bacteria, protozoa, fungi, rickettsiae,

and viruses.

Classifications of microorganisms

Bacteria – cocci round MRSA, strepthroat bacilli rods i.e. TB, pertussis, botulism spirilla spirals i.e. syphilis, cholera

Protozoa- one cell animal-like i.e. malaria

Fungi – plant-like organisms i.e. Yeasts, molds i.e. Ringworm, thrush etc.

Microorganisms (cont.)

Rickettsiae- parasitic i.e. Lice, ticks, fleas

Viruses - cannot reproduce without a cell, major risk to healthcare workers and are blood borne:

Examples of viruses, Hepatitis C, Hepatitis B, HIV.

Factors for Growth of Microorganisms

Most prefer warm, moist or wet, dark environment i.e. the human body

Oxygen needs vary

anaerobic no oxygen

aerobic needs oxygen

Pathogenic microorganisms

Cause diseases in different ways produce poisons toxins allergic reactions attack and destroy the cells

antibiotics are effective against bacteria not against viruses

Classes of Diseases and Infections

Endogenous

inside the body

i.e. tumors, congenital disorders Exogenous

outside the body

i.e. trauma, electric shock

Classes of Diseases and Infections (cont)

Nosocomial

acquired in healthcare facilities

i.e. Staph MRSA, pseudomonas Opportunistic

infections that only affect the

immunosuppressed

i.e. Kaposi’s sarcoma, pneumocystis carnii

Chain of Infection

Causative agent (pathogen, bacteria, virus)

Reservoir (place to live) i.e. human body.

Portal of exit (the way the pathogen escapes) i.e. urine, feces, secretions

Mode of transmission (transmitted to a reservoir or a host)

Direct or Indirect

Direct

person to person

sexual

contaminated hands Indirect

touching contaminated equipment

breathing droplets

insect bites

Mode of Transmissions

Portal of Entry

a way to enter a new host or new reservoir i.e. respiratory tract, breaks in the skin etc.

Susceptible Host

anyone who can contract the disease

weak immune systems

anyone with a breakdown in defense

mechanisms

Chain of Infection (cont.)

Infectious Agent

Portal of Exit

Reservoir

Mode of Transmission

Portal of Entry

Susceptible Host

Ending the chain

Breaking the chain Use aseptic technique asepsis Best is hand washing Levels or types of asepsis antiseptics, disinfection, sterilizationAntiseptics used in healthcare alcoholand betadine

Bacteria

One celled organism Multiply rapidly Classified by shape:

Cocci

Round or spherical in shape Types: Diplococci-occur in pairs-cause gonorrhea,

meningitis and pneumonia

Diplococci

Occur in pairs-cause gonorrhea, meningitis and pneumonia

Streptococci

Occur in chains Cause-strep throat

Staphylococci

Occur in clusters or groups Most common pyogenic(pus producing) Cause- boils, wound infections and toxic

shock

Bacilli Rod shaped Occur singly, pairs or in chains Many have flagella which are threadlike projections that allow them

to move Can form spores (thick walled capsules) when conditions for growth

are poor which make them DIFFICULT to kill!!! Cause-tuberculosis, tetanus, pertussis (whopping cough)

Spirilla

Spiral or corkscrew in shape Cause-syphilis and cholera

Protozoa One celled animal-like organisms Found in decayed materials and

contaminated water May have flagella Cause-malaria, trichomonas

Fungi Simple plant-like organisms that live on

dead organic matter Yeast and molds are common forms Cause-ringworm, athletes foot, yeast

vaginitis and thrush

Rickettsiae Parasitic Microorganisms Cannot live outside the cells of another living organism Found in fleas, lice, ticks and mites Transmitted to humans by the bites of these insects Cause-Typhus Fever, Rocky Mountain Spotted Fever

Viruses Smallest microorganisms Cannot reproduce unless inside another

living cell Spread from human to human by blood or

other body secretions Resistant to many disinfectants and not

affected by antibiotics Cause-Common cold, measles,

chickenpox herpes, warts, influenza

3 Viruses of Major Concern

Hepatitis B-transmitted by blood, serum and other body fluids-affects the liver-has a vaccine

Hepatitis C-transmitted by blood and blood containing body fluids-no symptoms or flu like symptoms-cause liver damage-vaccine being developed

Acquired Immune Deficiency Syndrome-caused by HIV virus-suppresses immune system-no cure or vaccine