Week 6 notes
Week 6 notes HTH 245
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Chapter 8: Guest speaker Epidemiology, Infection Prevention and Hospital Acquired infections ● Epidemiology ○ From the greek words ■ Epi: on or upon ■ Demi:people ■ Logos: the study of ○ The study of the distribution and determinants of healthrelated states or events in specified populations, and the application of this study to the control of health problems CDC ● People ○ Hippocrates ■ Behavior and habits affect our health ○ Edward Jenner ■ Proved cowpox and smallpox were related ■ Developed a smallpox immunization ○ Ignaz Semmelweis ■ Discovered relationship between hand hygiene and puerperal fever (postpartum fever: high fever after the mothers would give birth) ■ He was the savior of mothers ○ John Snow (the father of epidemiology) ■ Solved the Cholera epidemic in London ■ Mapped the city contaminated water was causing people to get cholera ○ Louis Pasteur ■ Pasteurization ■ Vaccination ■ Father of Germ theory ● Germ theory ○ Proposed preventing the entry of microorganisms into the body ○ Bacteria do not spontaneously generate ● Epidemiology concepts ○ Endemic: exists permanently in a particular region or population ■ Malaria ○ Epidemic: outbreak of disease that attacks many people at the same time ■ H1N1 ○ Pandemic: when an epidemic spreads worldwide ○ Morbidity: the state of being diseased or unhealthy within a population ■ Morbidity rate: the rate of illness ○ Mortality rate: the rate of death ○ Herd Immunity: ■ Vaccinations to protect those who can’t vaccinated ■ Effective when in the mid to high 90s ○ R❑ 0 : (R not) reproductive rate of a disease ● Chain of infection ○ Agent: ■ Microorganism that causes disease ○ Source ■ Where the disease survives ● Environmental ○ Soil, water ● Humans ○ Active carrier ○ Healthy carrier: don’t show signs or symptoms but can spread disease ○ Chronic carrier ● Zoonotic ○ 150 species carried by animals ○ Portal of exit ■ Serves more for person to person contract diseases ■ Coughing, sneezing, open wound, bleeding wound ○ Transmission ■ Direct transmission ■ Horizontal transmission ■ Vertical transmission ■ Indirect transmission ○ Portal of entry ■ Through the skin, wound, another entry into the body, sexual contact ■ Tzone ● Mucous membranes of the eyes, nose and mouth ● Touching face ● Inhalation ○ Susceptible host ■ Host must be susceptible to the microorganism ■ Unvaccinated, weakened immune system ■ dose/response ● Pathogen can overtake the body’s immune defenses ● How much pathogen the immune system can take on and if it can overcome it or not ○ If you can break the chain it renders the microorganism inactive, and stops spread of an infection ● Infection preventionist ○ Identify risks for the transmission of infection ○ Utilize evidence based practice to implement best practices that reduce the risk of disease transmission ■ CDC ○ Partner with healthcare providers and work together to provide safe and effective care to patients ■ CDC ○ Surveillance ■ Monitoring for identification of communicable diseases ● Daily microbiology culture review ● Monitor hospitals admissions, ED visits, patient census ○ Isolation, chief complaint, diagnosis ● Communication from physicians and hospital staff ○ Investigate disease clusters/outbreaks ○ Perform communicable disease exposure investigations ○ Report HAI (hospital acquired infections) data to various agencies ■ NHSN (CDC) ■ Local and state health department ○ Education ■ Bundles (BSI, UTI, VAP, SSI), best practice, hand hygiene, etc. ○ Implementing policies and procedures ■ Isolation ■ Bundles ■ Visitation policies ○ Partner with various interdisciplinary roles to ensure infection control principles are practiced ■ Making sure the rooms are clean ■ Dietary policies are being followed ○ Hand hygiene ■ Best method for preventing the spread of disease ■ 90% or greater hand hygiene compliance decreases all HAI ■ The 5 moments for hand hygiene ● 1. Before entry/patient care ● 2. Before clean/aseptic procedure ● 3. After body fluid exposure risk ● 4. After touching a patient/upon exiting ● 5. After touching patient surroundings/upon exiting ● Nosocomial infections (HAIs) ○ Infections acquired by patients during their hospital or other care facility during their stay ○ HAI’s contribute to an increase: ■ Morbidity and mortality ■ Patient stay ■ Antibiotic usage ■ Cost to the facility ● Many insurance companies do not reimburse for HAI ○ CLABSI ■ Central line associated bloodstream infection ■ Patients often have a central line placed for therapeutic treatment ■ Direct portal to patient's bloodstream ■ Proper care is crucial to prevent contamination and infection ● Cleaning of it, proper way of pushing drugs through it, preventing biofilms (which can harbor infection) ○ Cauti ■ Catheter associated urinary tract infection ■ Patients may have a foley catheter to assist with urination ■ Provides accurate I&O ■ Proper care is crucial to prevent contamination and infection ● Urine can be contaminated when it leaves the bladder ● Makes sure it doesn’t drain back up into the patient ● Proper cleaning ○ VAP ■ Ventilator associated pneumonia ■ Ventilators assist patients to achieve appropriate oxygenation ■ Appropriate care is needed to prevent contamination and infection ● Lots of bacteria and mucous in their mouth and respiratory tract ● Makes sure the bed is elevated at a certain degree ○ SSI ■ Surgical site infection ■ Postoperative infections that can have catastrophic effects for patients ■ Appropriate care before, during, and after is essential for appropriate, infectionfree recovery ● Administration of antibiotics ● Appropriate closure ● Appropriate dressing of the surgical site ● Can vary for pediatric and adult care ○ CDiff ■ Disruption of gut flora can cause C Diff flora to proliferate ■ Overuse of ABX (antibiotics) is a contributor ■ Environmental transmission does occur ● Spore forming bacteria (most hospital cleansers cannot clean it) ○ NHSN ■ National healthcare safety network ● A division of CDC ● Establishes criteria and definitions for monitoring and classifying HAI’s ● Establishes standardized definitions for classifying HAI’s for mandatory reporting ● All hospitals that receive medicare/medicaid funding must participate ○ Lower performing hospitals end up losing money for reimbursement ● National benchmarking against other hospitals ● Data is compared “like with like” ● Isolation ○ Used to separate, prevent the transmission of disease from one person to another ■ Symptomatic isolation ● Isolation based on patient symptoms ■ Laboratory confirmed isolation ● Isolation based on laboratory result or pending result ● How germs spread ○ Contact: touching germs through direct or indirect contact ○ Droplet: coughing can spread germs in the air for a short distance and fall onto a surface ■ Coughing, sneezing, talking ○ Airborne route: germs that can stay in the air ○ Contact transmission ■ Direct contact ■ Indirect contact ○ Droplet transmission ■ Droplets come in contact with host’s conjunctivae, nasal mucosa, or mouth ■ Droplets can only travel short distance ○ Airborne transmission ■ Airborne droplet nuclei or evaporated droplets contamination microorganisms ● Can remain in air for extended periods of time ● Can be dispersed widely by air currents ○ Vector transmission ■ Animals, fleas (just a carrier of the disease), humans, ● Standard precautions ○ Personal protective equipment (PPE) ■ Gloves ■ Face protection ■ Gown Chapter 9: Bacterial Diseases ● Routes of Transmission ○ Food and waterborne ■ Food Intoxication (food poisoning) ● Ingestion of bacterial toxins (with or without the microbe being present) ○ Antibiotics don’t help because there is no bacteria ● Botulism: ○ It is the most dangerous food intoxication and is caused by improperly homecanned foods (the can will bulge and the food smells yucky) ○ It is caused by Clostridium botulinum (gram positive anaerobic, spore forming bacillus commonly found in the soil) ○ The untreated death rate is 70% (but is low in the US) and when the disease is contracted there is an incubation period of 824 hours and death occurs within a day or two ○ Antibiotics don’t work because it isn’t an infection it is an intoxication ○ The neurotoxin that is produced leads to muscle and respiratory paralysis which eventually leads to the person not being able to breathe ● Staphylococcal food poisoning ○ It is the most common type of food poisoning (many cases remain undiagnosed) ○ It is caused by Staphylococcus aureus (a gram positive coccus) ○ It secretes an enterotoxin which causes intestinal tract symptoms (abdominal cramps, nausea, vomiting, diarrhea) ○ The main reservoir is the human nasal passages and is passed to others via food that is improperly stored ○ There is no antibiotic treatment you just have to wait it out ■ Foodborne infection: ● Bacteria multiply in the intestinal tract, secrete enterotoxin, and may invade cells of the intestinal tract ○ Enterotoxins: cause symptoms of nausea, vomiting, diarrhea and possibly blood stools ● Salmonellosis ○ Caused by gram negative bacilli in the genus Salmonella ○ It is caused by undercooked or unpasteurized foods/juices ○ It can also be transmitted through iguanas, turtles, lizards, snakes, and crows feet ○ It is a significant issue in the US ○ Children under age 5 are at an increased risk ● Typhoid fever ○ Caused by Salmonella typhi ○ Transmission is through flies and fomites ○ Infection is usually from fecallycontaminated foods or hands ○ The organism is able to survive in sewage, water, and certain foods ○ The organism invades the cells lining the small intestines, causing ulcers and bloody stools, fever, and possibly delirium ● Shigellosis ○ Caused by various species of Shigella (a gram negative bacillus) ○ Symptoms include gastroenteritis and dysentery ■ Severe diarrhea containing blood and mucus ■ Result ant dehydration can be deadly ○ The sources are eggs, shellfish, dairy products, vegetables, and water ○ Transmission occurs via the fecaloral route ○ The infectious dose (ID) is very low ○ Treatment involves oral or IV rehydration and possibly antibiotics ○ About one million annual deaths in developing countries ○ Day care centers are prone to outbreaks ● Cholera ○ Caused by Vibrio cholerae (a gram negative curved rod) and it secretes an exotoxin that causes diarrhea ■ Can cause severe dehydration and unless rehydration is instituted quickly, death results in only a few hours ■ Oral rehydration therapy ○ The mortality rate reaches up to 70% if untreated ○ Infection is caused from consuming fecallycontaminated water or food (including raw shellfish) ■ Reach es epidemic proportions in developing countries and there have been pandemics documented over the centuries ● E. Coli O157:H7 (enterohemorrhagic E. coli) ○ E. coli is a gram negative bacillus ■ They are a constituent of the normal flora of the large intestines of humans and animals. They are beneficial because they produce vitamins that are absorbed in the body ○ The consumption of rare meat (particularly hamburgers) and fresh spinach can all be contaminates of the infection ○ Recovery occurs within 510 days without any specific treatment ○ Children under age 5 are at a greater risk of death because of kidney damage resulting from toxinproduced hemorrhages in the kidney (hemolytic uremic syndrome) ● Enterotoxigenic E. coli ○ The most common cause of traveler’s diarrhea ○ E. coli is easy to culture and detect. It can be used as an indicator of fecal contamination ● Campylobacteriosis ○ Caused by the Campylobacter jejuni (a gram negative spiralshaped bacilli) ○ It is the most frequent cause of bacterial diarrhea in the US ○ Potential sources: poultry, cattle and unpasteurized milk ○ In 1998 it was reported that 70% of supermarket chicken was contaminated ○ It is the most common cause of gastroenteritis ■ There are about 1600 cases per year in the US ○ Lasts about one week and usually passes on it’s own ○ Many isolates are antibiotic resistant ■ This is because of the high amounts of antibiotics in animals ○ It takes less than 500 organisms to cause the illness (ID) ● Listeriosis ○ Caused by Listeria monocytogenes (a gram positive motile bacillus) ○ It has been isolated from soil, water, manure, plant materials, and the intestines of healthy animals ○ Contaminates: vegetables, meats, cheeses, ice cream, raw (unpasteurized) milk, cold cuts, hot dogs and soft cheeses ○ It can grow under refrigeration which adds to the problem ○ It is usually mild and subclinical in healthy adults and children ■ Infants , the elderly, the immunocompromised and pregnant women are at high risk ■ Fetuse s and newborns may become acutely ill from their infected mothers ■ Antibio tics must be given promptly to prevent infection and miscarriage of a fetus ● Pseudomembranous colitis (C. diff) ○ Caused by Clostridium difficile (C. diff) (a gram positive sporeforming bacillus) ○ Transmission is via fecaloral route ○ It is responsible for 13% of nosocomial infections and is associated with hospital patients on antibiotics ■ Depleti on of the normal flora by the use of antibiotics may allow C. difficile to “grow out,” usually causing mild to severe diarrhea ○ Symptoms: severe and diarrhea becomes debilitating, resulting in extreme weight loss ○ Airborne ■ Respiratory tract infections transmitted by air droplets or by contact with contaminated inanimate objects ■ They are categorized into upper and lower respiratory tract infections ■ Diphtheria ● Caused by Corynebacterium diphtheriae (a gram positive bacillus) ● An upper respiratory tract infection ● The exotoxin that is produced by the bacteria kills epithelial cells, which accumulate, forming a leathery pseudomembrane ● Death by suffocation may result ● The toxin diffuses into the bloodstream and may cause widespread damage, particularly to the heart ● It is rare in the US and the rest of the developed world ○ It is a significant problem in the underdeveloped world ○ Immunization programs are needed to control the disease ● Extreme swelling of the lymph nodes results in a “bull neck” appearance ■ Pertussis (Whooping cough) ● A highly infectious and potentially lethal disease caused by the gram negative coccobacillus Bordetella pertussis ● An upper respiratory tract infection ● Humans are the only reservoir; there is a particular threat to children under age 4 ● Bacteria are via contaminated droplets (talking, coughing, sneezing, and laughing) ● Symptoms: respiratory blockage causing violent and persistent coughing ○ These coughing episodes result in a need for oxygen, triggering deep and rapid inspirations causing the “whoop” sound ● It is considered a reemerging disease ● B. pertussis is endemic to the US ○ Epidemics occur every 35 years ■ Streptococcal infections ● A large group of gram positive cocci (infections range from mild to deadly) ● The most virulent of the group is Streptococcus pyogenes ● An Upper respiratory disease ● Streptococci reside in the human nose and throat ● They are transmitted by respiratory droplets or contact with sores or wounds ● Streptococcal pharyngitis (tonsillitis) is common in children 515 ● Longterm complications from repeated childhood strep infections ○ Glomerulonephritis, a kidney disease ○ Rheumatic fever, a condition involving the heart and joints ● Streptococcal toxic shock syndrome and necrotizing fasciitis are caused by invasive strep that cause lifethreatening infections ○ Toxins made by the bacteria can cause the tissue to die ■ Rare (650 to 800 cases annually in the US) ■ It is not contagious ■ Treatm ent: antibiotics, skin grafts, amputations, hyperbaric oxygen therapy ■ Meningitis ● An inflammation of the meninges ● An upper respiratory disease ○ Early diagnosis is essential; coldlike symptoms progress quickly to fever, possibly delirium, and stiffness in the neck and back ● Two common types ○ Neisseria meningitides ■ Menin gococcemia, responds to antibiotic therapy ■ A vaccine is available for epidemics ■ Colleg e students living in dormitories appear to be particularly susceptible to meningococcal meningitis ○ Haemophilus influenzae type b (Hib) ■ A gram negative bacillus ■ Hib meningitis occurs primarily in children under age five ■ Inciden ce has dropped with the Hib vaccine in early 1990s ■ About 10% of healthy people carry Hib in nose and throat ■ Legionnaire’s disease (legionellosis) ● A lower respiratory disease ● Caused by a gram negative bacillus, Legionella pneumophila ● Transmission is by inhalation of aerosols that come from a water source contaminated with L. pneumophila ● People middleaged and older, smokers, and those with chronic lung disease are the most susceptible ● Symptoms are fever, muscle pain, cough, and pneumonia (all typical of other respiratory infections) ● Death is usually by shock and kidney failure ● Prevention involves eliminating sources of warm, stagnant waters in which there is the potential for aerosolization ■ Tuberculosis ● Caused by the tubercle bacillus, Mycobacterium tuberculosis ● It is a lower respiratory tract infection ● About 10 million people are infected (most are in the developing world), with an annual death toll of 2 million ● About 8 million new cases develop annually ● Tuberculosis is made even worse by multiple drug resistant strains ○ Contact ■ Leprosy (Hansen’s disease) ● It is caused by Mycobacterium leprae ● Transmission via extended skin contact and droplets ● The incubation time is long; children are most susceptible ● Disease characterized by a variety of physical manifestations ○ Tumorlike skin lesions (lepromas) ○ Neurological damage to cooler areas of the body, such as the hands, feet, face, and earlobes ○ Lost ability to perceive pain in the fingers and toes, results in accidental burns and serious deformities ○ Antibiotics are unavailable to arrest the disease ■ Staphylococci ● Caused by Staphylococcus aureus (the most virulent of the staph) ● Staphylococci are in the normal flora of the skin, mouth, nose, and throat ● Unless the skin barrier is broken (by burns or trauma), staphylococci are normally harmless ● Cause of purulent (pus containing) skin lesions, pimples, boils, carbuncles ● Can progress into systemic (bloodborne) infections ● Methicillinresistant S. aureus (MRSA) ○ Acquires in hospitals, athletic facilities, residence halls, military barracks ● Impetigo is a superficial blister that produces an oozing highly infectious yellow discharge ● Scalded skin syndrome causes blistering skin due to an exfoliative toxin ● Toxic shock syndrome from S. aureus strains that secrete the TSSexotoxin, eliciting high fever, nausea, vomiting, peeling of the skin (particularly on the palms and the soles), and a dangerous drop in blood pressure that leads to lifethreatening shock ■ Peptic ulcers ● Caused by Helicobacter pylori (a gram negative curved bacteria) not stress or diet ● Transmission is via personto person contact ● Infection (and ulcers) can be cured with antibiotics ● Infection is also associated with gastric cancer ● 20% of the population under age 40 and 50% over 60 are infected in the United States; only 10% ever get ulcers ■ STDs are transmitted by sexual contact; they continue to be a serious health problem due to the emergence of antibiotic resistant strains and the AIDS virus (HIV) ● Syphilis ○ Caused by Treponema pallidum ○ Humans are the only known reservoirs, there is no vaccine ○ Most US cases are in the 2039 year old age group; men who have sex with men accounted for about two thirds of the cases ○ Spirochetes can pass across the placenta, resulting in congenital syphilis; stillbirths and deformities are possible ○ Syphilis progresses through a series of three stages: ■ The primary stage is marked by a painless chancre (sore) ■ The secondary stage is systemic, a rash dispersed on the body, but characteristically includes the palms and soles ■ A third of those untreated progress to tertiary syphilis, which can develop over the next 40 years (during which the cardiovascular and nervous systems, especially, show degenerative changes) ● Gonorrhea (the clap) ○ Caused by Neisseria gonorrhoeae ○ Second only to chlamydia, infection rate highest in sexually active teens and young adults ○ May be transmitted via vaginal, oral, or anal sex ○ In males a purulent discharge from the penis and burning during urination is common ● Chlamydia ○ Caused by Chlamydia trachomatis ○ It is the most common STD ○ It is most prevalent in sexually active young adults and teens ○ 70% of female and 30% of male infections are asymptomatic ○ Males are subject to inflammation of the testes and infertility ○ Females have the most complications, including pelvic inflammatory disease, abnormal pregnancy, and infertility ○ Soilborne ■ Anthrax ● Caused by Bacillus anthracis ● Is primarily found in grazing animals, mostly sheep and cattle; infection is most prevalent in agricultural areas ● It is a likely candidate for use in biowarfare, because these spores can be readily spread by missiles and bombs ● Antibiotics are effective against all forms of anthrax, but early intervention is necessary; vaccine is available for high risk workers ○ Inhalation anthrax (woolsorter's disease) the most sever of the three, is an occupational hazard for humans exposed to contaminated dead animals and animal parts who are most likely to inhale spores ○ Cutaneous anthrax is acquired by contact with bacilli or spores via wool, hides, leather, or hair products ○ Gastrointestinal anthrax results from ingesting undercooked meat contaminated with B. anthracis , leading to acute inflammation of the gastrointestinal tract, abdominal pain, vomiting of blood, and severe diarrhea ■ Tetanus (lockjaw) ● A noncommunicable disease ● Acquired by exposure to spores of Clostridium tetani ● Tetanospasmin is a neurotoxin; the second most deadly bacterial toxin ● Tetanus bacilli are ubiquitous and are abundant in soil, manure, and dust ● Spores germinate and bacilli multiply in deep, anaerobic, puncture wounds (from gunshot wounds, animal bites, etc.) ● Tetanus prevents muscle relaxation, resulting in uncontrollable contraction ● Death occurs by suffocation ● The number of tetanus cases in the US is about 50100 per year, absent or inadequate immunization leads to higher incidence in underdeveloped countries ● Neonatal tetanus is common in the first month of life ○ The disease is prevalent in poor nations when an infant is delivered under unsanitary conditions to a non immunized mother (the umbilical cord may be contaminated when cut) ■ Leptospirosis (swamp fever) ● Caused by Leptospira interrogans ● Reservoirs are various animals (dogs, rats, etc.) ○ Rats appear to be the most significant source of disease ● Transmission is spread via urine; spirochetes penetrate the human skin, enter the bloodstream, and rapidly invade virtually all organs ● May be transmitted by ingesting water contaminated with rat urine ● It is not transmitted from human to human ● Leptospirosis can be a serious and potentially fatal disease, with symptoms including jaundice, fever, headache, nausea, and chills ● Leptospirosis is most common in tropical countries ○ Arthropod Borne ■ Plague (black death) ● Caused by the gram negative bacillus Yersinia pestis (one of the most virulent bacteria known) ● From 1347 to 1351, one third of the population of Medieval Europe (about 25 million people) died of the black death ● Plague is a reemerging infection because of increased incidence globally ● Plague is zoonosis; many mammals, primarily rodents (gophers, squirrels, mice, rats, etc.) serve as reservoirs ○ Infection frequently results from an infected flea bite ○ Sporadic cases in southwest US due to prairie dogs or rodents ■ Bubonic plague ● The bacilli localize in the lymph nodes of groin, armpits, and neck and cause the nodes to swell (buboes) ● The bacilli can spread to the bloodstream, liver, lungs, and other sites, hemorrhages under the skin and turns black ● Not normally infectious, mortality over 50% ■ Pneumonic plague ● Occurs when those with the bubonic plague form develop pneumonia and transmit the bacteria to others by coughing and through saliva ○ Approaches 1005 fatality without early treatment ○ Vaccine is protective for only a few months and is only given to persons at high risk ■ Septicemic plague ● Results from the spread of bacteria from the lungs to other parts of the body ● Acquired by contact of contaminated hands, food, or objects with the mucous membranes of the nose or throat ● It is considered to be 100% fatal ■ Ehrlichiosis ● Caused by a gram negative intracellular bacillus ● Emerging tickborne zoonosis, first reported in humans in 1986 ● Symptoms are fever, headache, general malaise, and possibly a rash ● Primarily along the atlantic coast in the south central united states ● There are two forms of the disease; both respond well to antibiotics ■ Lyme Disease ■ Rocky Mountain Spotted Fever ● How to reduce the risk of foodborne and waterborne infections (table 9.2) ○ Wash hands frequently ○ Cook raw beef and poultry products thoroughly ○ Avoid unpasteurized milk and juices and any food made from them ○ Properly wash utensils, cutting boards, and raw fruits and vegetables ○ Beware of double dippers (with food) ○ Avoid eating at disreputable joints ○ Avoid food and drinks sold by street vendors, particularly when traveling abroad ○ Frequently wash kitchen sponges in the dishwasher ○ Do not share eating utensils, water bottles, or other such items ○ Do not swim in contaminated waters ● Other bacteria besides streptococci that can cause lifethreatening necrotizing fasciitis ○ Klebsiella ○ Clostridium ○ E. coli ○ Staphylococcus aureus ○ Aeromonas hydrophila