Infection Control

Infection Control Chapter 14 Diversified Health Occupations, 7th ed.

14:1 Principles of Infection Control • Understanding is essential to all health care workers • Provide a basic knowledge of how disease is transmitted • Main emphasis on prevention of disease transmission

Microorganisms or Microbes • Small living organisms • Not visible to the naked eye • Microscope must be used to see them • Found everywhere in the environment • Found on and in the human body • Many are part of normal flora of body • May be beneficial (continues)

Microorganisms or Microbes(continued) • Called “nonpathogens”when not harmful to the body • Called “pathogens” (germs) when able to harm the body • Cause infections and diseases (continues)

Microorganisms or Microbes(continued) • Most prefer warm environments • Most prefer darkness • Need source of food and moisture • Need for oxygen varies • Aerobic (requires oxygen to live) • Anaerobic (lives without oxygen) • Human body is ideal supplier of all the requirements

Microbe Classifications • Bacteria • Protozoa • Fungi • Rickettsiae* • Viruses • Helminths

Bacteria • Simple, one-celled organisms • Multiply rapidly • Classified by shape and arrangement (continues)

Bacteria(continued) • Cocci are round or spherical in shape • Diplococci—in pairs (gonorrhea, meningitis, pneumonia) • Streptococci—in chains (Strept throat, rheumatic fever) • Staphylococci—clusters or groups (Boils, UTI, wound infections, Toxic Shock Syndrome)

Bacteria(continued) • Bacilli are rod shaped • Occur singly, in pairs, or in chains • May have flagella • Ability to form spores • Examples of diseases • Tuberculosis • Tetanus • Pertussis • Botulism • Diptheria • Typhoid

Bacteria(continued) • Spirilla are spiral or corkscrew shaped • Diseases • syphilis • cholera

Antibiotics • Antibiotics are used to kill bacteria • Some strains of bacteria have become antibiotic-resistant • When antibiotic-resistant, the antibiotic is no longer effective against the bacteria • Example: • MRSA (Methicillin-resistant staphylococcus aureus)

Protozoa • One-celled, animal-like organism • Found in decayed materials and contaminated water • May have flagella for movement • Some are pathogenic • Examples of diseases • Malaria • Amebic dysentery • Trichomonas • African sleeping sickness

Fungi • Simple, plant-like organisms that live on dead organic matter • Yeast and molds are 2 common types • Can be pathogenic • Examples of diseases • Ringworm • Athlete’s foot • Antibiotics do not kill fungi, need antifungal medications

Rickettsiae • Parasitic microorganisms which means they cannot live outside the cells of another living organism • Transmitted to humans by the bites of insects (e.g., fleas, lice, ticks, mites) • Examples of diseases- Rocky Mountain spotted fever, typhoid fever • Antibiotics are effective against many of them

Viruses • Smallest microorganisms, seen on with the use of an electron microscope • Must be inside another living cell to reproduce • Spread by blood and body secretions • Very difficult to kill bc resistant to many disinfectants, not affected by antibiotics • Cause many diseases

Viruses • Diseases include: • Common cold • Measles • Mumps • Chicken pox • Herpes • Warts • Influenza • Polio

Viruses(continued) • Viruses infecting animals can mutate to infect humans • Examples include: • Severe acute respiratory syndrome (SARS) • West Nile Virus (WNV) • Monkeypox • Ebola and Marburg • H5N1 (avian flu) • H1N1 (swine flu)

Viruses(continued) • Three other diseases of major concern to Health Care workers include: • Hepatitis B • Hepatitis C • AIDS

Virus—Hepatitis B • Also called “serum hepatitis” • Caused by Hepatitis B Virus • Transmitted by blood, serum, and other body secretions • Affects the liver • Can lead to destruction and scarring of liver cells • Vaccine is available for protection given in a series of 3 injections

Virus—Hepatitis B(continued) • By federal law, employers must provide vaccine at no cost to employees with occupational exposure to blood or other body secretions • If employee refuses, written statement must be signed documenting refusal

Hepatitis C • Caused by Hepatitis C Virus • Transmitted by blood and blood-containing body fluids • Many infected individuals are asymptomatic • Others have mild symptoms • Can cause severe liver damage

Hepatitis C (continued) • Currently, no vaccine ready for use • Vaccine is in developmental stage • Extremely difficult to destroy HCV and HBV • Both can survive and remain active for several days in dried blood • Health care workers must follow precautions to protect against virus

Acquired Immune Deficiency Syndrome (AIDS) • Caused by the Human Immunodeficiency Virus (HIV) • Suppresses the immune system • Individual becomes susceptible to cancers and infections that would not affect a healthy person • No cure presently and no vaccine • Take precautions for prevention

Helminths • Multicellular parasites, otherwise known as worms or flukes • Are transmitted: • By eating contaminated food • Being bitten by infected insects • When worms enter the skin

How Pathogens Cause Infection and Disease • Some produce poisons, called toxins • Some cause an allergic reaction • Others attach and destroy the living cells they invade

Classifications of Diseases and Infections • Endogenous • Exogenous • Nosocomial • Opportunistic

Endogenous • Originates within the body • Examples: • metabolic disorders • congenital abnormalities • tumors • infections caused by microorganisms within the body

Exogenous • Originates outside the body • Examples: • radiation • chemical agents • trauma • electric shock • temperature extremes

Nosocomial • Acquired in a health care facility • Usually present in facilities and carried by health care workers to the patient • Many are antibiotic-resistant • Can cause serious and even life-threatening infections

Nosocomial(continued) • Examples are • Staphylococcus • pseudomonas • enterococci • Infection-control programs are used in facilities to prevent and deal with nosocomial infections

Opportunistic • Infections that occur when the body’s defenses are down • Usually do not occur in normal immune system • Examples (in individuals with AIDS) • Kaposi’s sarcoma (rare type of cancer) • Pneumocystiscariniipneumonia

Chain of Infection • Must be present for disease to occur and spread from one individual to another • Causative agent (Pathogen) • Reservoir (Host) – an area where causative can live • Human body • Animals • Environment • Fomites – objects contaminated with infectious material, commonly doorknobs, bedpans, urinals, linens, instruments and specimen containers

Portal of exit • Way for agent to escape from reservoir • Mode of transmission • A way that causative agent can be transmitted to another reservoir or host • Direct contact • Indirect contact • Portal of entry • Way for causative agent to enter a new reservoir or host • Susceptible host • A person likely to get an infection or disease

Common Body Defenses • Mucous membranes • Cilia • Coughing and sneezing • Hydrochloric acid (HCL) in the stomach • Tears – contain bacteriocidal chemicals • Fever • Inflammation response – leukocytes • Immune response – antibodies, chemicals

Ending the Chain of Infection • Eliminate any step in the chain and infection is stopped • Follow practices to interrupt or break the chain • Remember, pathogens are everywhere • Prevention is a continuous process

Aseptic Techniques • Asepsis:defined as the absence of disease-producing microorganisms • Sterile: means free from all organisms, including spores and viruses • Contaminated: means organisms and pathogens are present

Aseptic Techniques • Major aim: maintaining cleanliness and eliminating or preventing every aspect of contamination

Common Aseptic Techniques • Thorough handwashing • Good personal hygiene • Disposable gloves • Cleaning instruments and equipment • Proper cleaning of environment

Levels of Aseptic Control • Antisepsis: • Antiseptics prevent or inhibit growth of pathogenic organisms, but not effective against spores or viruses • Can be used on the skin • Alcohol, betadine • Disinfection: • A process that destroys pathogenic organisms, but not always effective against spores or viruses • Can irritate skin, used mainly on objects • Bleach solutions • Sterilization: • A process the destroys all microorganisms, including pores and viruses • Ex. steam under pressure (autoclave), gas, radiation, and chemicals on objects

Summary • Important for health care workers to know and use proper aseptic techniques at all times • Prevents spread and transmission of disease

14:2 Bioterrorism • Bioterrorism: use of microorganisms or biologic agents for warfare to infect humans, animals, or plants • Have been used over time by different nations not only in war but also on innocent people

Examples from history • 1346 – throwing dead plague victims over wall of a city to cause epidemic • 1763 – British giving Delaware Indians items contaminated with smallpox • WWI – Germans using animal and human pathogens • WWII – Japanese experimenting on POW with different pathogens • 1960s – various countries developing biologic weapons • 1995 – Release of sarin gas in Tokyo • 2001 – Anthrax contaminated mail in US

Biologic Agents • Microorganisms with characteristics suitable for bioterrorism: • Inexpensive, available, easily produced, spreads quickly • Maintains its survival • Brings death or disability • Travels from person to person • Difficult to prevent/treat

Biologic Agents(continued) • High priority agents include: • Smallpox: contagious and infectious disease, result of the Variolavirus • Vaccine can protect against some types of smallpox • One type, hemorrhagic smallpox, is usually fatal • Anthrax: infectious disease caused by spores of Bacillus anthracis • Spores highly resistant to destruction • Can live in soil for years • Plague: infectious disease from the bacteria Yersinia pestis • Transmitted by bites of infected fleas

Biologic Agents(continued) • Botulism: paralytic illness resulting from a nerve toxin from the bacteria Clostridium botulinum • Toxin causes muscle paralysis • Tularemia: infectious disease from the bacteria Fracisellatularensis • Filoviruses: infectious diseases causing severe hemorrhagic fever • 2 are Ebolavirus and Marburgvirus • No effective treatment exists • 50-90% on infected individuals die

Preparing for Bioterrorism • Bioterrorism attack would result in a public health emergency • Would have impact on health care facilities • Social disorder would ensue • Comprehensive plan was prepared – Bioterrorism Act of 2002

Preparing for Bioterrorism(continued) • Bioterrorism Act 2002 passed by Congress and signed into law • Involves local, regional, state, and national government and includes: • Early detection by communities • Public to be notified • Infection control and education • Funding available for studying organisms, developing vaccines, reseraching treatments, determining preventative actions

Preparing for Bioterrorism(continued) • Guidelines and restrictions • Nationwide immunizations • Protection of food/water supplies • Trained personnel available • Emergency management controls • Investigation of potential threats • Preparation of health care facilities • Efficiency of communication

Summary • All health care workers need to be aware of bioterrorism • Attack could occur at any time • Being prepared and properly trained will result in saving many lives

14:3 Washing Hands • Major aspect of standard precautions • Most important aseptic technique • Hands are perfect media for the spread of pathogens

Infection Control