32 Principles of Asepsis.

32 Principles of Asepsis

Learning Outcomes 32.1 Explain the historical background of infectious disease prevention. 32.2 Identify the types of microorganisms that cause disease. 32.3 List some infectious diseases, and identify their signs and symptoms. 32.4 Discuss the importance of preventing antibiotic resistance in a health-care setting. 32.5 Describe ways you can help prevent antibiotic resistance in health-care settings.

Learning Outcomes (cont.)
32.6 Explain the disease process. 32.7 Explain how the body’s defenses protect against infection. 32.8 Describe the cycle of infection. 32.9 Identify and describe the various methods of disease transmission. 32.10 Explain how you can help break the cycle of infection.

Introduction Our bodies are amazing structures that defend us against infections under normal circumstances You will learn about: Disease-causing microorganisms How the body fights disease Ways infections occur Antibiotic-resistant organisms Importance of patient education on the proper use of antibiotics Learning Outcomes: 32.2 Identify the types of microorganisms that cause disease. 32.4 Discuss the importance of preventing antibiotic resistance in a health-care setting. 32.5 Describe ways you can help prevent antibiotic resistance in health-care settings.

History of Infectious Disease Prevention
Throughout history people have attempted to discover Causes of infection How to prevent infections How to treat infections Learning Outcome: 32.1 Explain the historical background of infectious disease prevention.

History of Infectious Disease Prevention (cont.)
Scientist Contribution Edward Jenner (1749–1823) Developed first effective vaccine Used cowpox to vaccinate against smallpox Ignaz Semmelweis (1818–1865) and Oliver Wendell Holmes (1809–1894) Promoted handwashing as a means of reducing the spread of puerperal fever to women in childbirth Learning Outcome: 32.1 Explain the historical background of infectious disease prevention.

Scientist Contribution Louis Pasteur (1822–1895) Helped develop the germ theory of infectious disease, stating that disease is caused by microorganisms Joseph Lister (1827–1912) Helped develop germ theory Introduced aseptic techniques through the use of antiseptics on wounds, surgical sites, and surgical instruments Learning Outcome: 32.1 Explain the historical background of infectious disease prevention.

Scientist Contribution Robert Koch (1843–1910) Developed a set of proofs, known as Koch’s postulates, claiming that microbes cause disease Sir Alexander Fleming (1881–1955) Discovered penicillin Learning Outcome: 32.1 Explain the historical background of infectious disease prevention.

Remarkable advances in the past century Threat of infection still present New infectious diseases AIDS Ebola Resistant diseases MRSA VRSA Multidrug-resistant TB Learning Outcome: 32.1 Explain the historical background of infectious disease prevention. MRSA: Methicillin-resistant Staphylococcus aureus VRSA: Vancomycin-resistant Staphylococcus aureus

Right! Apply Your Knowledge
Why is the threat of infection still present even though great advances have been made in controlling infections over the past century? ANSWER: The threat of infection is still present because of new diseases and diseases that have become resistant to treatments. Right!

Microorganisms and Disease
Microorganisms live all around us Pathogens Microorganisms capable of causing disease Evade host defenses People avoid infections most of the time Many microorganisms are beneficial or harmless Normal defenses resist infection Conditions are not favorable for pathogens to grow and be transmitted Learning Outcome: 32.2 Identify the types of microorganisms that cause disease. Pathogens comprise only a small portion of the total number of microorganisms that exist in a given environment.

Microorganisms and Disease (cont.)
Classification Characteristics Example Disease Prions* Infectious particle made of protein No nucleic acid Reproduction unknown Pr P Creutzfeldt-Jakob disease Mad cow disease Learning Outcome: 32.2 Identify the types of microorganisms that cause disease. * Experts disagree as to whether prions are directly responsible for disease or merely aid an unknown agent in causing disease.

Classification Characteristics Example Disease Viruses DNA or RNA surrounded by protein coat Reproduced in living cells Very small Varicella-zoster virus Chickenpox Bacteria Single-celled Reproduce quickly Mostly asexual reproduction Vibrio cholerae Cholera Learning Outcome: 32.2 Identify the types of microorganisms that cause disease.

Classification Characteristics Example Disease Protozoans Single-celled Reproduction mostly asexual Entamoeba histolytica Amebic dysentery Fungi Multicellular Reproduction is sexual and asexual Candida albicans Candidiasis Helminths Multicellular parasitic Contain specialized organs Sexual reproduction Enterobius vermicularis Pinworms Learning Outcome: 32.2 Identify the types of microorganisms that cause disease.

Correct! Apply Your Knowledge
In many cases, we avoid contracting infections when exposed to microorganisms. What are the reasons for this? ANSWER: This is because: many microorganisms are beneficial or harmless we have normal defenses to resist infection conditions are not favorable for the pathogen to grow and be transmitted. Correct!

Infectious Diseases Knowing signs and symptoms of common infectious diseases can help protect against exposure Learning Outcome: 32.3 List some infectious diseases, and identify their signs and symptoms.

Infectious Diseases (cont.)
Chickenpox (Varicella) Contagious viral infection Incubation period of 7 to 21 days Itchy rash  fluid-filled blisters Slight fever, headache, general malaise Spread by direct, indirect, droplet, or airborne transmission Isolate until all blisters have scabbed over 1996 – live vaccine approved Learning Outcome: 32.3 List some infectious diseases, and identify their signs and symptoms. Many states require reporting chickenpox to the state or county department of health.

Common cold Viral infections of upper respiratory tract No isolation needed Commonsense precautions to prevent spread Use tissues when coughing or sneezing Wash hands frequently Use disposable dishware, if possible Incubation – 2 to 3 days Learning Outcome: 32.3 List some infectious diseases, and identify their signs and symptoms. Common cold is transmitted from person to person through direct or indirect contact.

Croup Most often caused by a virus Characterized by a harsh, barking cough, difficulty breathing, hoarseness, and low-grade fever Most common in infants and young children Symptoms lessened by humidification of air, rest, and clear fluids Commonsense precautions to prevent spread Learning Outcome: 32.3 List some infectious diseases, and identify their signs and symptoms.

Diphtheria Bacterial infection of nose, throat, and larynx Symptoms: pain, fever, respiratory obstruction Incubation – 2 to 5 days Isolation required Antibiotic therapy (fatal if untreated) Immunization available Learning Outcome: 32.3 List some infectious diseases, and identify their signs and symptoms. Cases of diphtheria must be reported to the state or county health department.

Epstein-Barr Virus Common human virus 95% of adults have had virus 35 – 50% of teens develop mononucleosis Symptoms – fever, sore throat, swollen lymph nodes Virus remains dormant for life Occasionally reactivates as tumors Learning Outcome: 32.3 List some infectious diseases, and identify their signs and symptoms. Tumors associated with Epstein-Barr Burkitt’s lymphoma Carcinoma of the nasopharynx

Haemophilus Influenzae Type B Bacterial infections in infants and young children Spread – direct, indirect, and droplet transmission Incubation – 3 days Upper respiratory symptoms, fever, drowsiness, body aches, diminished appetite Monitor closely – bacterial meningitis Learning Outcome: 32.3 List some infectious diseases, and identify their signs and symptoms.

Hepatitis Viral infection of liver Spread through blood or fecal-oral route HIV/AIDS Human immunodeficiency virus Acquired immune deficiency syndrome Learning Outcome: 32.3 List some infectious diseases, and identify their signs and symptoms.

Influenza (Flu) Symptoms – fever, chills, headaches, body aches, upper respiratory congestion Isolation and commonsense precautions Vaccines Live, attenuated virus – nasal spray Inactivated virus – IM injection Annual vaccination People at risk for complications People older than 50 years old People in close contact with persons at risk for complications Learning Outcome: 32.3 List some infectious diseases, and identify their signs and symptoms.

Measles (Rubeola) Infectious viral disease Spread by droplets or direct transmission Initial symptom of fever develops 8 to 13 days after exposure, followed by a characteristic itchy rash 14 days after exposure Isolation for 7 days after rash appears Keep children under 3 years old away from anyone with the disease Reportable to state or county health dept. Learning Outcome: 32.3 List some infectious diseases, and identify their signs and symptoms.

Meningitis Inflammation and infection of protective coverings of brain and spinal cord and the fluids around them Viral – milder form Clears in 1 to 2 weeks without treatment Aseptic meningitis Learning Outcome: 32.3 List some infectious diseases, and identify their signs and symptoms.

Meningitis Bacterial – serious, life-threatening, requiring immediate treatment Vaccination available for people in high-risk groups Symptoms – red, blotchy rash, confusion, delirium, light sensitivity, headache, fever and chills, nausea and vomiting, sleepiness, stiff neck May spread through exchange of respiratory and throat secretions Reportable to state or county health dept. Learning Outcome: 32.3 List some infectious diseases, and identify their signs and symptoms. High-risk groups Elderly Children younger than 5 Children in daycare or schools College students living in dorms or other close environments People with chronic illnesses Any health-care worker who has had direct contact with an infectious patient’s oral secretions is considered at increased risk of acquiring the infection.

Mumps Viral infection Primarily affects salivary glands Incubation – 2 to 3 weeks Pain related to inflammation of parotid gland and fever Isolate until glandular swelling stops Reportable to state or county health dept. Learning Outcome: 32.3 List some infectious diseases, and identify their signs and symptoms.

Pertussis (Whooping Cough) Highly contagious bacterial infection of respiratory tract Symptoms – fever, sneezing, runny nose, quick short coughs, characteristic “whoop” during inhaled breath following coughing fit Isolate for 3 weeks following onset of spasmodic coughs Reportable to state or county health dept. Learning Outcome: 32.3 List some infectious diseases, and identify their signs and symptoms.

Roseola Rose-colored rash possibly caused by human herpes virus Infants and young children Incubation 5 to 15 days Symptoms – sudden, high fever; sore throat; swollen lymph nodes; rash Rubella (German Measles) Highly contagious viral disease Direct or droplet transmission Incubation 16 to 18 days Symptoms – fever and itchy rash Vaccination available Reportable Learning Outcome: 32.3 List some infectious diseases, and identify their signs and symptoms. Roseola: Seizures may accompany cases with very high fever, but the disease is usually not serious.

Streptococcal pharyngitis (strep throat) Bacterial infection of throat Sore throat, swelling of pharyngeal mucosa, fever, headache, nausea, abdominal pain Treat with antibiotics Scarlet fever Bacteria becomes systemic Characteristic “strawberry rash” Incubation 7 to 10 days Isolate 7 days Learning Outcome: 32.3 List some infectious diseases, and identify their signs and symptoms. Complications of strep throat Scarlet fever Rheumatic fever Acute post-streptococcal glomerulonephritis

Streptococcal pharyngitis (cont.) Rheumatic fever Occurs after apparent recovery from strep throat Autoimmune disorder – antibodies to streptococci cross-react with heart tissues Symptoms – carditis, ECG changes, joint pain and inflammation, fever Acute post-streptococcal glomerulonephritis Inflammation of glomerulus of the kidney resulting in inadequate filtering of the blood Symptoms – swelling of hands and feet, decreased urine output, hypertension, protein in urine Learning Outcome: 32.3 List some infectious diseases, and identify their signs and symptoms. Rheumatic fever: Heart valves are especially prone to damage by antibodies against streptococci. Antibodies: Highly specific proteins that attach themselves to foreign substances.

Tetanus Acute infectious bacterial disease following a contaminated puncture wound Incubation – 3 to 21 days Late symptoms – lockjaw, paralysis No isolation needed, but reportable Learning Outcome: 32.3 List some infectious diseases, and identify their signs and symptoms.

Tuberculosis Infectious bacterial disease affecting mainly lungs Symptoms – night sweats, productive cough, fever, chills, fatigue, unexplained weight loss, diminished appetite, bloody sputum Incidence – higher in urban centers Transmission Mycobacterium tuberculosis Droplet Learning Outcome: 32.3 List some infectious diseases, and identify their signs and symptoms. Factors that contribute to continued high incidence of TB Infection with HIV increases risk for developing TB Population of U.S. is shifting to include a higher number of people from countries that have a higher incidence of TB Number of people living in environments known to impose increased risk, such as long-term institutional settings, homeless centers, and medically underserved neighborhoods, has increased. Public health-care system is unable to meet needs of its constituents, resulting in patients who remain untreated. New drug-resistant strains of the TB pathogen are appearing, requiring longer and more potent therapy regimens, which are harder to enforce and with which many patients do not comply.

Tuberculosis (cont.) Increasing resistance to TB Early diagnosis, prompt treatment Compliance with treatment regimen Preventing TB Vaccination – BCG (not used in the U.S.) Causes false-positive with TB skin test Learning Outcome: 32.3 List some infectious diseases, and identify their signs and symptoms. Risk factors for TB infection HIV infection or any disease state that weakens the immune system Intravenous drug use Previous TB infection Diabetes mellitus End-stage renal disease Low body weight

Tuberculosis (cont.) Treating TB Mantoux TB test Positive test = Induration – skin turns red and becomes raised and hard Positive result from immunization or exposure to TB bacteria Treatment based on area affected and type of TB involved Patients must complete entire course of treatment – 12 to 18 months on medication Isolation Learning Outcome: 32.3 List some infectious diseases, and identify their signs and symptoms. Patient education The disease Expected course of treatment Anticipated outcome Measures patients can take to prevent the spread of the disease

Preventing the Spread of TB
Containment of the tuberculosis bacteria Patient measures Covering mouth Proper disposal of tissues Take medication as directed Avoid close contact with others Air out their room Office measures Use negative pressure area Use personal respirator Apply standard sanitization, disinfection, and sterilization techniques Learning Outcome: 32.3 List some infectious diseases, and identify their signs and symptoms.

Excellent! Apply Your Knowledge
How can the spread of many infectious diseases can be limited or prevented? ANSWER: The spread of many infectious diseases can be limited or prevented by using commonsense precautions: Using tissues when coughing or sneezing Washing hands frequently Using disposable dishware Excellent!

Drug-Resistant Microorganisms
MRSA – methicillin/oxacillin-resistant S. aureus VRE – vancomycin-resistant enterococci VISA – vancomycin-intermediate S. aureus VRSA – vancomycin-resistant S. aureus ESBLS – extended-spectrum beta-lactamases PRSP – penicillin-resistant Streptococcus pneumoniae Learning Outcome: 32.4 Discuss the importance of preventing antibiotic resistance in a health-care setting.

Drug-Resistant Microorganisms (cont.)
MRSA and VRE Most common in non-hospital health-care facilities Community-associated MRSA Increasing in incidence PRSP Common in patients seeking care in physicians’ offices and clinics (pediatrics) Learning Outcome: 32.4 Discuss the importance of preventing antibiotic resistance in a health-care setting.

Drug-Resistant Microorganisms (cont.)
Risk factors for development of infections by drug-resistant organisms Advanced age Invasive procedures Prior use of antibiotics Repeated contact with health-care system Severity of illness Underlying diseases or conditions Learning Outcome: 32.4 Discuss the importance of preventing antibiotic resistance in a health-care setting.

Preventing Antibiotic Resistance
Four strategies to reduce incidence of antibiotic-resistant microorganisms Prevent infection Diagnose and treat infection appropriately Use antibiotics carefully Prevent transmission of infections Learning Outcome: 32.5 Describe ways you can help prevent antibiotic resistance in health-care settings.

Apply Your Knowledge What strategies reduce the incidence of antibiotic-resistant microorganisms? ANSWER: Strategies to reduce the incidence of antibiotic-resistant microorganisms include: Prevent infections Diagnose and treat infections appropriately Use antibiotics carefully Prevent transmission Good Job!

Disease Process Begins with microorganisms finding host
Grows with specific requirements Proper temperature pH Moisture level Virulence – microorganism’s disease-producing power Damage is caused by: Depleting nutrients Reproducing themselves Making body cells the target of body’s own defenses Producing toxins Learning Outcome: 32.6 Explain the disease process. The temperature within the human body, the body’s neutral pH, and the body’s dark, moist environment are prime conditions for the growth of many types of microorganisms.

Disease Process (cont.)
Once exposed to a pathogen, the body goes through 4 stages of illness: Incubation – begins at first exposure; ends when first symptom appears Prodromal – begins at first onset of symptoms; generally short Invasion – numbers of organisms are greatest; symptoms are most pronounced Convalescent – patient regains normal health status Learning Outcome: 32.6 Explain the disease process.

Apply Your Knowledge SUPER! What are the four stages of illness?
ANSWER: The four stages of illness are: Incubation – begins at first exposure; ends when first symptom appears Prodromal – begins at first onset of symptoms; generally short Invasion – numbers of organisms are greatest; symptoms are most pronounced Convalescent – patient regains normal health status SUPER!

The Body’s Defenses First lines of defense
Immunity – condition of being resistant to pathogens and the disease they cause First lines of defense Skin Sweat glands Mucous membranes Cilia Lacrimal glands Saliva Hydrochloric acid Lysozyme Learning Outcome: 32.7 Explain how the body’s defenses protect against infection.

The Body’s Defenses (cont.)
Resident normal flora – microorganisms found in the body Provide a barrier against pathogens Normally live in balance Become pathogenic when host’s defenses are compromised Opportunistic infections Infections occurring when a host’s resistance is low Learning Outcome: 32.7 Explain how the body’s defenses protect against infection. The skin, nose, mouth, vagina, rectum, and intestines are all colonized by resident normal flora. Typical opportunistic infections: Pneumocystis carinii Candida

Nonspecific Defenses Inflammation Signs Purpose Redness Localized heat
Swelling Pain Purpose Summon immunologic agents to site Begin tissue repair Destroy invading microorganisms Learning Outcome: 32.7 Explain how the body’s defenses protect against infection.

Nonspecific Defenses (cont.)
Steps of inflammation Initial constriction, then dilation of blood vessels, causing redness and heat Fluid leakage from local vessels  swelling Scar tissue formation Chronic inflammation Damage to tissues Loss of function Learning Outcome: 32.7 Explain how the body’s defenses protect against infection.

Nonspecific Defenses (cont.)
Phagocytosis White blood cells (phagocytes) engulf and digest pathogens Three types Neutrophils – found in pus Monocytes – formed in bone marrow and become Macrophages when they migrate to specific tissues Found in lymph nodes, liver, spleen, lungs, bone marrow, and connective tissue Deliver antigens (foreign substances) to lymphocytes Learning Outcome: 32.7 Explain how the body’s defenses protect against infection.

Humoral Immunity Lymphocytes – B cells and T cells
T cells activate B cells to produce antibodies to neutralize an antigen Memory B cells respond quickly to produce antibodies in later invasions Specific antibodies are produced in response to specific antigens Antibodies attract phagocytes, which destroy antigens Learning Outcome: 32.7 Explain how the body’s defenses protect against infection.

Humoral Immunity (cont.)
Types of immunity Active – body produces own antibodies Natural active Artificial active Passive – antibodies that are produced outside body enter the body Natural passive Artificial passive Complement Proteins activated by antibodies Helps white blood cells destroy pathogens Learning Outcome: 32.7 Explain how the body’s defenses protect against infection.

Cell-Mediated Immunity
T cells attack invading pathogen directly Helper T cells Activate Killer T cells Bind with antigen and kill it Suppressor T cells Slow down or stop attack after antigen is destroyed Memory T cells Respond quickly to another attack by same antigen Learning Outcome: 32.7 Explain how the body’s defenses protect against infection. Cell-mediated defenses often result in inflammation of the affected area.

Impressive! Apply Your Knowledge
What is the difference between active and passive immunity? ANSWER: Active immunity is long-term immunity in which the body produces its own antibodies. Passive immunity results when antibodies produced outside the body enter the body. Both can be natural or artificial. Impressive!

Click for Cycle of Infection
A reservoir host – animal, insect, or human body capable of sustaining pathogen growth Carrier – unaware of presence of pathogen Subclinical case – unnoticeable infection Endogenous infection – normally harmless microorganisms become pathogenic Exogenous infection – pathogen introduced into the body Learning Outcome: 32.8 Describe the cycle of infection. Click for Cycle of Infection

Cycle of Infection (cont.)
Means of exit – how the pathogen leaves the host Nose, mouth, eyes, or ears Feces or urine Semen, vaginal fluid, or other reproductive discharge Blood or blood products Learning Outcome: 32.8 Describe the cycle of infection. Click for Cycle of Infection

Means of transmission – how a pathogen spreads to a host Airborne Blood-borne During pregnancy or birth Foodborne Vector-borne Living organism that carries microorganisms to another person Touching Direct Indirect through fomites Inanimate reservoir of pathogens Drinking glass, door knob, etc. Learning Outcomes: 32.8 Describe the cycle of infection. 32.9 Identify and describe the various methods of disease transmission. Indirect transmission is possible only if the pathogen is capable of existing independently of the reservoir host. Congenital infection: One that is present in a child at the time of birth (transmitted from mother). Most common vectors Fleas Flies Mosquitoes Ticks Click for Cycle of Infection

Means of entrance Enter through any cavity lined with mucous membrane Mouth, nose, vagina, rectum Ears, eyes, intestinal tract, urinary tract, reproductive tract, breaks in the skin Learning Outcome: 32.8 Describe the cycle of infection. Click for Cycle of Infection

Susceptible host Individual with little or no immunity to infection by a pathogen Host factors influencing susceptibility Age Genetic predisposition Nutritional status Other disease processes Stress levels Hygiene habits General health Pathogen factors Number and concentration Virulence Point of entry Learning Outcome: 32.8 Describe the cycle of infection. Click for Cycle of Infection

Learning Outcome: 32.8 Describe the cycle of infection. Back

Environmental factors Dense populations Animals – unpasteurized milk Insects Economic and political factors Availability of transportation Population growth rates Sexual behavior Learning Outcome: 32.8 Describe the cycle of infection.

Breaking the Cycle Asepsis – condition in which pathogens are absent or controlled Maintain strict housekeeping standards Adhere to government guidelines to protect against disease Educate patients in hygiene, health promotion, and disease prevention Learning Outcome: 32.10 Explain how you can help break the cycle of infection.

Nice Job! Apply Your Knowledge What are fomites?
ANSWER: Fomites are inanimate objects such as clothing, water, and food that serve as a means of transportation for microorganisms. Nice Job!

In Summary 32.1 Infection control has been a problem throughout history. Though there have been many advances, controlling infection continues to be a challenge for doctors. 32.2 There is great variety in the types of pathogenic organisms. Types of potentially infectious microorganisms include prions, viruses, bacteria, protozoans, fungi, and helminths.

In Summary (cont.) 32.3 It is important to be familiar with the diseases that infect people so that you can protect your patients, coworkers, and yourself. These diseases include but are not limited to chickenpox, croup, diphtheria, hepatitis, influenza, measles, mumps, and polio Antibiotic resistance of microbial pathogens is a growing problem. The number of infections for which there is little or no treatment is increasing. It is the responsibility of health-care workers to use antibiotics wisely.

In Summary (cont.) 32.5 The CDC began a campaign to prevent antimicrobial resistance. There are four strategies outlined in the campaign: 1) prevent infection; 2) diagnose and treat infection appropriately; 3) use antibiotics carefully; and 4) prevent transmission of infections There are numerous human pathogens. These pathogens cause disease by damaging the body in a number of ways including depleting nutrients needed by cells, reproducing themselves within body cells, making body cells the targets of the body’s own defenses, and producing toxins that damage cells and tissues.

In Summary (cont.) 32.7 The body is able to protect itself from disease through the use of several lines of defense. These lines of defense may be nonspecific or specific In order for an infection to occur, five elements must be in place. There must be a reservoir host, a means of exit, a means of transmission, a means of entrance, and a susceptible host Direct disease transmission occurs when the pathogen moves immediately from one host to another. Indirect transmission is possible only if the pathogen is able to survive outside the host for some period of time.

End of Chapter 32 In today's world, new infections and diseases can spread across the country and even across the world in a matter of days, or even hours, making early detection critical. ~ John Linder Member of the U.S. House of Representatives, Georgia

32 Principles of Asepsis.

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