CHAPTER © 2011 The McGraw-Hill Companies, Inc. All rights reserved. Core A Principles of Asepsis

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Introduction –Antibiotic-resistant organisms –Importance of patient education on the proper use of antibiotics You will learn about: –Disease-causing microorganisms –How the body fights disease –Ways infections occur Our bodies are amazing structures that defend us against infections under normal circumstances

© 2011 The McGraw-Hill Companies, Inc. All rights reserved History of Infectious Disease Prevention Throughout history people have attempted to discover –Causes of infection –How to prevent infections –How to treat infections

© 2011 The McGraw-Hill Companies, Inc. All rights reserved History of Infectious Disease Prevention (cont.) ScientistContribution 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

© 2011 The McGraw-Hill Companies, Inc. All rights reserved History of Infectious Disease Prevention (cont.) ScientistContribution 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

© 2011 The McGraw-Hill Companies, Inc. All rights reserved History of Infectious Disease Prevention (cont.) ScientistContribution 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

© 2011 The McGraw-Hill Companies, Inc. All rights reserved History of Infectious Disease Prevention (cont.) Remarkable advances in the past century Threat of infection still present –New infectious diseases AIDS Ebola –Resistant diseases MRSA VRSA Multidrug-resistant TB

© 2011 The McGraw-Hill Companies, Inc. All rights reserved 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.

© 2011 The McGraw-Hill Companies, Inc. All rights reserved 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

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Microorganisms and Disease (cont.) ClassificationCharacteristicsExampleDisease Prions*Infectious particle made of protein No nucleic acid Reproduction unknown Pr PCreutzfeldt- Jakob disease Mad cow disease * Experts disagree as to whether prions are directly responsible for disease or merely aid an unknown agent in causing disease.

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Microorganisms and Disease (cont.) Classification CharacteristicsExampleDisease 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

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Microorganisms and Disease (cont.) Classification CharacteristicsExampleDisease 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

© 2011 The McGraw-Hill Companies, Inc. All rights reserved 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!

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Infectious Diseases Knowing signs and symptoms of common infectious diseases can help protect against exposure

© 2011 The McGraw-Hill Companies, Inc. All rights reserved 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

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Infectious Diseases (cont.) 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

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Infectious Diseases (cont.) CroupMost 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

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Infectious Diseases (cont.) DiphtheriaBacterial 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

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Infectious Diseases (cont.) 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

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Infectious Diseases (cont.) 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

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Infectious Diseases (cont.) HepatitisViral infection of liver Spread through blood or fecal-oral route HIV/AIDS Human immunodeficiency virus Acquired immune deficiency syndrome

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Infectious Diseases (cont.) 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

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Infectious Diseases (cont.) 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.

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Infectious Diseases (cont.) MeningitisInflammation 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

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Infectious Diseases (cont.) MeningitisBacterial – 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.

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Infectious Diseases (cont.) MumpsViral 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.

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Infectious Diseases (cont.) 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.

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Infectious Diseases (cont.) 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

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Infectious Diseases (cont.) 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

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Infectious Diseases (cont.) 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

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Infectious Diseases (cont.) TetanusAcute infectious bacterial disease following a contaminated puncture wound Incubation – 3 to 21 days Late symptoms – lockjaw, paralysis No isolation needed, but reportable

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Infectious Diseases (cont.) 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

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Infectious Diseases (cont.) 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

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Infectious Diseases (cont.) 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

© 2011 The McGraw-Hill Companies, Inc. All rights reserved 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

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Apply Your Knowledge 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 How can the spread of many infectious diseases can be limited or prevented? Excellent!

© 2011 The McGraw-Hill Companies, Inc. All rights reserved 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

© 2011 The McGraw-Hill Companies, Inc. All rights reserved 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)

© 2011 The McGraw-Hill Companies, Inc. All rights reserved 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

© 2011 The McGraw-Hill Companies, Inc. All rights reserved 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

© 2011 The McGraw-Hill Companies, Inc. All rights reserved 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!

© 2011 The McGraw-Hill Companies, Inc. All rights reserved 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

© 2011 The McGraw-Hill Companies, Inc. All rights reserved 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

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Apply Your Knowledge 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 What are the four stages of illness?

© 2011 The McGraw-Hill Companies, Inc. All rights reserved The Body’s Defenses 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

© 2011 The McGraw-Hill Companies, Inc. All rights reserved 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

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Nonspecific Defenses Inflammation –Signs Redness Localized heat Swelling Pain –Purpose Summon immunologic agents to site Begin tissue repair Destroy invading microorganisms

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Nonspecific Defenses (cont.) –Steps of inflammation 1.Initial constriction, then dilation of blood vessels, causing redness and heat 2.Fluid leakage from local vessels  swelling 3.Scar tissue formation –Chronic inflammation Damage to tissues Loss of function

© 2011 The McGraw-Hill Companies, Inc. All rights reserved 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

© 2011 The McGraw-Hill Companies, Inc. All rights reserved 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

© 2011 The McGraw-Hill Companies, Inc. All rights reserved 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

© 2011 The McGraw-Hill Companies, Inc. All rights reserved 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

© 2011 The McGraw-Hill Companies, Inc. All rights reserved 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!

© 2011 The McGraw-Hill Companies, Inc. All rights reserved 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 Click for Cycle of Infection

© 2011 The McGraw-Hill Companies, Inc. All rights reserved 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 Click for Cycle of Infection

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Cycle of Infection (cont.) 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. Click for Cycle of Infection

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Cycle of Infection (cont.) 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 Click for Cycle of Infection

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Cycle of Infection (cont.) –Pathogen factors Number and concentration Virulence Point of entry  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 Click for Cycle of Infection

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Cycle of Infection (cont.) Back

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Cycle of Infection (cont.) Environmental factors –Dense populations –Animals – unpasteurized milk –Insects –Economic and political factors –Availability of transportation –Population growth rates –Sexual behavior

© 2011 The McGraw-Hill Companies, Inc. All rights reserved 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

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Apply Your Knowledge ANSWER: Fomites are inanimate objects such as clothing, water, and food that serve as a means of transportation for microorganisms. What are fomites? Nice Job!

© 2011 The McGraw-Hill Companies, Inc. All rights reserved In Summary 32.1Infection control has been a problem throughout history. Though there have been many advances, controlling infection continues to be a challenge for doctors. 32.2There is great variety in the types of pathogenic organisms. Types of potentially infectious microorganisms include prions, viruses, bacteria, protozoans, fungi, and helminths.

© 2011 The McGraw-Hill Companies, Inc. All rights reserved In Summary (cont.) 32.3It 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. 32.4Antibiotic 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.

© 2011 The McGraw-Hill Companies, Inc. All rights reserved In Summary (cont.) 32.5The 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. 32.6There 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.

© 2011 The McGraw-Hill Companies, Inc. All rights reserved In Summary (cont.) 32.7The 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. 32.8In 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. 32.9Direct 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.

© 2011 The McGraw-Hill Companies, Inc. All rights reserved 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 End of Chapter 32