SCIENCE BIOS-242N-Bios242 final review/Chamberlain College of Nursing

Final Exam Definitions to know: • Immunology: Study of the body’s specific defenses against pathogens. • Halophiles: salt lovers environment • Spirochete: Group of helical, Gram-negative bacteria with axial filaments that cause the organism to corkscrew, enabling it to burrow into a host’s tissues. • Mutualism: Symbiotic relationship in which both members benefit from their interaction. • Signs: Objective manifestations of disease observed or measured by others • Symptoms: Subjective characteristics of disease felt only by the patient • Nosocomial disease (healthcare associated disease): A disease acquired in a healthcare facility. • Nosocomial infection (healthcare associated infection): An infection acquired in a healthcare facility. • Sty: Inflamed bacterial infection of the base of an eyelid. Folliculitis Called a sty when it occurs at the eyelid base can spread to surrounding tissues producing furuncles, carbuncles in groups • Lymphangitis: Condition in which inflamed lymphatic vessels become visible as red streaks under the skin. • Candidiasis: Term for several opportunistic diseases caused by infection with Candida species. • Pathogen: A microorganism capable of causing disease. • Zoonoses: Diseases that are naturally spread from their usual animal host to humans. • Fomites: Objects inadvertently used to transfer pathogens to new hosts, such as a glass or towel. • Infections: Successful invasion of the body by a pathogenic microorganism. • Lipid A: The lipid component of lipopolysaccharide, which is released from dead Gram- negative bacterial cells and can trigger shock and other symptoms in human hosts. • Septicemia: any microbial infection of the blood that produces illness • Bacteremia: bacterial septicemia • Toxemia: release of bacterial toxins into the blood • Blastomycosis- transmitted to human via bird • Superoxide dismutase peroxide anion, eliminate superoxide radicals • Superoxide dismutase – eliminate superoxide radicals Catalase and peroxidase – removal of hydrogen peroxide Types of healthcare associated infections (HAIs) • Exogenous - Pathogen acquired from the health care environment • Endogenous - Pathogen arises from normal microbiota as a result of factors within the healthcare setting • Iatrogenic - Results from modern medical procedures • Superinfections - Use of antimicrobial drugs reduces competition from some resident microbiota, allowing other microbes to thrive Know the characteristics of prokaryotic cells – i.e. no nucleus 1. they have no nuclear membrane 2. their DNA is not wound around histones 3. the cell walls are made of a chemical called peptidoglycan 4. they do not have complex membrane-bound organelles What does prokaryotic mean? • Any unicellular microorganism that lacks a nucleus. Classification includes bacteria and archaea. Know how we measure bacterial cells. The standard method is the plate count, which is the usual way to count microbes. The purpose of this method is to just use a sample of dilutions on a bacterial culture and counting. First, 3 of the 0.1ml dilutions are poured to duplicate the agar plates. One then sterilizes the glass spreader by dipping it in alcohol and burning it. Once the spreader is cooled, 0.1 of the inoculum is spread over the agar plates till the media doesn’t look wet. Repeat the process for the remaining plates. Once all that is done, it must be incubated at room temperature. It can then be counted in the end, all of the colonies. The advantage of this method is that it is super easy to do and one counts CFUs if they aren’t broken up. It isn’t complicated to pull through this method. As for the disadvantage, the count might not be as accurate. Not only this, the time to complete this method with all the dilutions, plating, smearing, and incubation waiting take a bit of time. The turbidimetric method is a much more complicated process. This process deals with the bacteria growing in a culture, creating a cloud. The cloud is thus counted and it can be converted to cell numbers. The first step is to take the broth, wipe the outside of the cuvette, and insert it into the sample holder in the spectrophotometer. One must discard the broth and use the same cuvette to measure the diluted sample in density. The next day, one counts the number of colonies on each plate. This is the turbidimetric method. An advantage to this method is that it is way faster compared to the other method. As for the disadvantage, it can’t be used for microbes that are grouped together. Lower densities can’t be measured as well with this method. Know the constituents of the cell wall of both gram positive and gram-negative bacteria. Gram-positive bacteria Gram-negative bacteria • Thick multi-layer peptidoglycan cell wall with Teichoic acid • Contain unique polyalcohols called teichoic acids • Lack outer layer cell membrane • Single lipid membrane • Presence of up to 60% mycolic acid in acid-fast bacteria • Purple (crystal violet dye) • Thin single-layer peptidoglycan • Outer layer consist of lipopolysaccharide (lipid A) o Lipid A cause fever, vasodilation, inflammation, shock, and blood clotting o May impede the treatment of disease • Red or pink (safranin) Know the principle of the gram stain and how it works. • helps in the classification and differentiations of microorganisms. • is the properties of certain bacteria cell walls to retain the crystal violet dye. The cell walls for Gram-positive microorganisms have a higher peptidoglycan and lower lipid content than Gram-negative bacteria. o Crystal Violet, the primary stain o Iodine, the mordant o A decolorizer made of acetone and alcohol (95%) o Safranin, the counterstain Know the different oxygen requirements for bacterial growth: • Microaerophilic: requires low levels of oxygen environment • Obligate aerobes require oxygen environment • Obligate anaerobes: No oxygen environment • Facultative anaerobes can grow with or without oxygen, but their ability to use aerobic respiration pathways enhances their growth near the surface. • Aerotolerant aerobes can grow equally well with or without oxygen; their growth is relatively evenly distributed throughout the medium. • Chemoautotrophic: uses inorganic energy sources to grow • Hyperthermophilic: grows in extremely hot temperature • Thermophilic: grow in warm environment • Mesophile - moderate temperature • Halophile - salt environment Know which growth phase makes microorganisms more susceptible to antimicrobials and WHY. • Bacteria are most susceptible to antimicrobial drugs during the logarithmic (log) phase, when the cells are actively dividing. Because such cells are actively metabolizing during this stage, they are particularly vulnerable to antibiotics. Know what a protozoan cyst stage is and why it’s important. • A motile trophozoite is the feeding stage of a typical protozoan. • A cyst, a resting stage that is resilient to environmental changes, is formed by some protozoa • Can last long in host, lack of nutrients, host to host, doesn't matter temperature • Unfavorable environmental conditions such as lack of nutrients or oxygen, extreme temperatures, lack of moisture and presence of toxic chemicals Know the properties of enzymes.**** 37 degrees work best in our bodies, not for everything • Hydrolases – catalyze hydrolysis • Isomerases – rearrange atoms • Ligases or polymerases – join chemicals • Lyases – split molecules w/o using water • Oxidoreductases – transfer of electrons • Transferases – transfer of function groups Know the byproducts of • glycolysis: ATP, pyruvic acid, NADH • Krebs cycle: FADH2, NADH, CO2, ATP • electron transport: H+ ions and ATP Know what happens during the intracellular and extracellular stages of a virus. Intracellular stages of a virus Extracellular stages of a virus • Capsid removed • Virus exists as nucleic acid • Called virion • Protein coat (capsid) surrounding nucleic acid • Nucleic acid and capsid, also called nucleocapsid • Some have phospholipid envelope • Outermost layer provides protection and recognition sites for host cells Know what filtration is and why it would be a necessary/suitable method of providing a sterile solution. Filtration is the passage of a fluid (either a liquid or a gas) through a sieve designed to trap particles—in this case, cells or viruses—and separate them from the fluid. Researchers often use a vacuum to assist the movement of fluid through the filter. • Health care and laboratory workers routinely use filtration to prevent airborne contamination by microbes. Know the characteristics of the first line of defense for the immune system. • The skin, the mucous membranes, and the variety of fluids that are produced by the body. o First, the skin has many layers of protection that few microbes can penetrate. o Second, these layers are shed, removing potential pathogens. o Third, the epidermis has epidermal dendritic cells that are phagocytic. • The mucous membranes also play a role for a variety of reasons. They contain tightly packed cells that are continually shed and replaced. In addition, the production of mucus acts to trap pathogens, and the cilia, which are often present, beat synchronously to remove microbes. Bodily fluids serve to dilute and wash away microbes. These fluids include tears, saliva, urine, vaginal secretions, blood, and menstrual flow. Other physical processes include defecation and vomiting. • Know the side effects of using tetracycline. • Stains teeth yellow Be able to explain why we don’t use antibiotics to treat colds or the flu. ESSAYS • In common parlance, antibiotics are antibacterial or antifungal drugs, whereas colds are caused by virus • Antibiotics cannot destroy viruses because they specifically target the machinery found in bacteria. Since viruses do not contain any of this machinery, the antibiotic does not have a target to attack. Know characteristics that are shared by the skin and mucous membrane. SKIN MUCOUS membrane • Many cells layers • Outer layers cell are dead, inner layers are alive • No mucus • Dry • One to a few cell layers • Cells are alive • Mucus presented • Moist • defensins, lysozyme present • Defensins, lysozyme, sebum present • Constant shedding and replacing cells • Cilia presented in the trachea, uterine tube • Constant shedding and replacing cells Packed cells Know the characteristics of the different immunoglobulin classes. IgM IgG IgA IgE IgD pentamer monomer Monomer, dimer monomer monomer First antibody produced; later switches to IgG They are the most common type of antibody in the blood during the initial phases of an immune response. Most common and longest- lasting antibody NK cells interacts agglutination Associated with body secretions (ex. Breast milk) agglutination Involves in response to parasitic infections and allergies A cause of basophil and eosinophil degranulation unknown Understand how cervical cancer is diagnosed and the most common causative agent. • Human papillomavirus (HPV) a non-enveloped virus accounted as the most important causative agent of cervical cancer, most common, pap smear Know the different stages of an infectious disease. 1. Incubation period: is the time between infection and occurrence of the first symptoms or signs of disease. [ex. 2-3 days (flu) wks-mths (Hep B) yrs (HIV)] 2. Prodromal period: early signs and symptoms, but not infectious (se- not feeling well, headache, fever, upset stomach) 3. illness period: maximum symptoms, most contagious, most severe 4. decline period: the body gradually returns to normal as the patient’s immune response and/or medical treatment vanquish the pathogens. 5. Convalescence period: recovery, feeling better # of organisms are declining still contagious! Know the causative agents of: • Impetigo: Staphylococcus pyogenes and Staphylococcus aureus • necrotizing fasciitis: Streptococcus pyogenes and Staphylococcus aureus • (Chickenpox) Shingles: varicella zoster virus (Occurs following re-activation of the virus) teardrops on rose petals • Ringworm: Microsporum spp. include Microsporum canis • Hansen’s disease (Leprosy): poor response to Mycobacterium leprae (from armadillos) • African sleeping sickness ( transfer to people by the bite of the tsetse flies: Trypanosoma brucei • Plague: Yersinia pestis (Y. pestis) bacteria • Lyme disease: bacterium, spirochete Borrelia burgdorferi Pathogenic processes of: causes, causative agent, highlighted in red o R. rickettsii does not secrete any toxins (most severe) o Disease occurs from damage to blood vessels o Caused by tick bites • Encephalitis: a highly fatal disease carried by pigs; and mosquito-borne chikungunya, which causes severe joint pain and sometimes death, brain encephalitis inflammation of brain • Tetanus: Clostridium tetani o Tightening of the jaw (lockjaw) o Spasms and contractions may spread to other muscles o Pathogen and virulence factors ▪ Clostridium tetani is causative agent ▪ Found in soil, dust, and the intestines of humans and animals ▪ Vaccine contains inactivated tetanospasmin o Pathogenesis ▪ Can acquire through break in skin or mucous membrane ▪ Distance of infection from CNS determines incubation period • Brucellosis: Brucella is a coccobacillus that causes brucellosis Brucella melitensis o Fluctuating fever that spikes undulant fever • streptococcal pharyngitis: (strep throat-purulent pocket on throat) is an inflammation of the pharynx caused by streptococci. The back of the pharynx appears red, with swollen lymph nodes and purulent (pus-containing) abscesses covering the tonsils o Pathogen ▪ Caused by Histoplasma capsulatum ▪ Pathogenic yeast form at human body temperature ▪ Histoplasma produces several proteins that inhibit macrophage activation and other host defenses o Pathogenesis and epidemiology ▪ Humans inhale airborne spores from the soil ▪ Prevalent in the eastern U.S. • helicobacter pylori: —causes most peptic ulcers from stress • Mumps: Epidemic parotitis o Caused by the mumps virus ▪ Humans are the only natural host o Once a very common childhood disease o Nearly nonexistent in developed countries because of immunization o No specific treatment for mumps o Infected individuals develop lifelong immunity • strep throat: causes by Group A streptococci (Streptococcus pyogenes) from droplets, saliva • Bacterial gastroenteritis : Shigellosis (traveler’s Diarrhea) Escherichia coli Other diseases to know and fully understand: • hepatitis A: a viral liver disease that is transmitted through ingestion of faeces contaminated food and water or through direct contact , oral-fecal transmit • Cytomegalovirus (CMV): like herpesvirus; fluids, disease affects fetuses, newborns, and immunodeficient patients and is transmitted via bodily secretions. • Schistosomiasis: (swimmer’s itch) “snail fever”; a potentially fatal disease. Snails are the intermediate host. o Pathogenesis and epidemiology ▪ Humans are principal host for most Schistosoma species ▪ Schistosomiasis is not found in the U.S. o Diagnosis, treatment, and prevention ▪ Diagnosed by identifying eggs in stool or urine sample ▪ Treated with praziquantel ▪ Prevention requires avoiding potentially contaminated water Be able to explain how sterilizations procedures can still be considered sterilization even when they don’t kill all microbes present. essay Sterilization removes or destructs all microbes including viruses and bacterial endospores except prions. Sterilization procedure do not deactivate prions, though they are destroyed by incineration or by autoclaving in concentrated sodium hydroxide. Know about the DTaP vaccine and the BCG vaccine. Dtap vaccine (diphtheria, tetanus, acellular pertussis) BCG vaccine • used to prevent pertussis is a combination vaccine protecting against multiple diseases simultaneously. • Prevent Tuberculosis and leprosy Know the differences in the different types of immunity (passive, active, acquired, innate, etc) Passive active Naturally/ Artificially acquired Innate (nonspecific) Naturally acquired • Antibodies are transferred from mother to child either placenta or breast milk Artificially acquired • Health care workers introduce antigens in vaccines, the body responds with antibody or cell- mediated immune responses, including the production of memory cells. (given Naturally acquired • The body responds to antigens that enter naturally, such person contract a disease Artificially acquired • Antigen introduced by vaccine, your body actively making antibodies vaccination Naturally acquired • Response against antigens encountered in daily life Artificially acquired • Response to antigens introduced via a vaccine • first two lines of defense • External physical barriers to pathogens • Protective cells, bloodborne chemicals, and processes virus and antibodies) triggers an immune response (only antibodies) Know the features of primary, secondary, and tertiary syphilis: Treponema pallidum • Primary syphilis: hard, non-painful, genital chancre that disappears after three to six weeks. • Secondary syphilis: sore throat, headache, mild fever, malaise, myalgia, and rash that lasts several weeks or months. Ulcerated blister BLISTERRRSSS ^ treatable • Latent syphilis: generally asymptomatic; lasts for decades. • Tertiary syphilis: dementia, blindness, paralysis, and gumma lesions (is difficult to diagnose) Know the components of the specific immune response and the nonspecific immune response Specific Immune Response Nonspecific Immune Response • Cell-mediated immune responses (specific cells) o primarily to fight intracellular pathogens and abnormal body cells. o The body induces cell-mediated immune responses only against specific endogenous antigens. o the activation of a specific clone of cytotoxic T cells • Antibody immune responses o activates only in response to specific pathogens. o the activity of B lymphocytes in antibody immune responses. o antigens can induce an antibody immune response without the assistance of a helper T cell (Th cell); therefore, these antigens are called T-independent antigens, and they trigger response of T-independent antibody immunity • Humoral Immunity response: is mediated by antibody molecules that are secreted by plasma cells. (Dealing with body fluids) • Skin and mucous membranes of the respiratory, digestive, urinary, and reproductive systems • dendritic cells that are phagocytic • Know the virulence factors of Staphylococcus aureus. essay • Staphylococci have at least three categories of virulence factors that allow them to produce disease: enzymes, structures that enable them to evade phagocytosis, and toxins. o Enzymes: produce a number of enzymes that contribute to their survival and pathogenicity o Structures that enable them to evade phagocytosis: defenses by synthesizing loosely organized polysaccharide slime layers ▪ The slime layer also facilitates attachment of staphylococcal biofilms to artificial surfaces such as catheters, shunts, artificial heart valves, and synthetic joints. o Toxins: possesses several toxins that contribute to virulence ▪ Cytolytic toxins disrupt the cytoplasmic membranes of a variety of cells. ▪ Leukocidin kills leukocytes, providing Staphylococcus with additional protection against phagocytosis, and epidermal cell differentiation inhibitor is a protein • Know the various conditions caused by Staphylococcus aureus along with their laboratory diagnosis. essay • Skin disease: folliculitis, sty, furuncle, carbuncle • Staphylococcal scalded skin syndrome caused by exfoliative toxins • Impetigo • Staphylococcal toxic shock syndrome • Bacteremia • endocarditis • Pneumonia • Food poisoning Know which are the bacterial STDs? • gonorrhea • Syphilis • Chlamydial Infections Chlamydia trachomatis most common reportable STD in the US Know the pathogenesis, laboratory diagnosis and treatment of gonorrhea. 765-766 • Pathogenesis: Neisseria gonorrhoeae adhere, via their fimbriae, capsules and endotoxin, to epithelial cells of the mucous membranes lining much of the genital, urinary, and digestive tracts of humans • Laboratory diagnosis: genetic probes provide direct, accurate, rapid detection of N. gonorrhoeae in clinical specimens. Indirect fluorescent antibody test • Treatment: Treated with broad-spectrum cephalosporin (azithromycin or doxycycline to treat gonorrhea). Know the pathogenesis, laboratory diagnosis, and treatment of HIV infection. HIV is not AIDS; HIV infection typically leads to AIDS in untreated patients. • Pathogenesis: HIV targets helper T (CD4) cells , invades, and replicates and then, burst and kill cells. • Laboratory diagnosis: Physicians diagnose AIDS fewer than 200 CD4 , one or more opportunistic diseases and presence of HIV. • Treatment: “cocktail” o protease inhibitors prevents making of new virus o reverse transcriptase inhibitors prevent from replication of virus The HIV virus attaches to CD4 lymphocytes, but must interact with the fusin protein to enter cells. The virus cannot gain entry to cells lacking the fusin protein, so all the donated bone marrow stem cells are naturally resistant to HIV infection. In the course of treatment for leukemia the recipient s blood cells are eliminated and replaced by the donor blood cells. The patient s successful treatment for leukemia supplied him with blood cells naturally resistant to HIV infection, so even if residual virus is present in latently infected cells, the virus could not spread to his new cells. This constitutes a reasonable definition of cured, but is not a practical treatment for all HIV infected persons. Be able to describe the cellular structures or processes that can be targets of antimicrobial agents. • Cell wall synthesis • Cell membrane synthesis • Nucleic acid synthesis • Protein synthesis • Action as antimetabolites • inhibit s DNA, RNA, ribosomes • essay Be able to describe the pathogenesis, signs, symptoms of yeast infections. (essay question) • Pathogenesis: (Candida albicans) C. albicans normally lives in the vagina in competition with lactobacilli and other bacteria. • Signs: Vaginal candidiasis manifests as white mucoid colonies growing on the mucous membrane of the vagina and the skin covering the vaginal labia. • Symptoms: The yeast produces severe vaginal itching and burning, which urination intensifies. Sexual intercourse can be very painful. The vaginal discharge is often curdlike and slight. Be able to describe the different reservoirs of human infections and examples of diseases for each type. (essay question) For a pathogen to enter a new host, it must survive in some site from which it can infect the new host. These sites are considered reservoirs, which include the following: 1. Animal reservoirs, such as domestic or wild animals (spreads from animal to human called zoonoses) Examples: rabies, West Nile fever. Ex Yersinia pestis are transmitted by fleas that migrate between animal hosts and humans. It can also be transmitted by human to human 2. Human carriers, which are individuals who are infectious and may be either asymptomatic or symptomatic. Examples: AIDS, tuberculosis. 3. Nonliving reservoirs of infection such as soil, water, and food. Examples: cholera, tetanus. EX. Prion infected protein that infects the normal protein in a human unfolding their protein like the infected protein. Description, animal, disease Be able to explain how the respiratory tract is protected from invasion by pathogens. (essay question) The respiratory tract has a protection layer called the mucous membrane that has secretion of goblet cell that produce mucus, which the mucus prevent attachment of bacteria. It act as a protective barrier between the respiratory tract and pathogens., cilia helps move mucus containing bacteria out of the upper respiratory system. Be able to explain how the skin serves as a natural defense to infections. (Essay question) • The skin is salty (salt is left behind as sweat evaporates from the skin) and covered with sebum, a lipid produced by sebaceous glands of the skin that contains a variety of antimicrobial chemicals. The outer layer of skin is also composed primarily of dead, dry skin cells that provide little nourishment or protection for microbes. These skin cells are continually being sloughed off, making it difficult for microbes to attach to invade the skin. Dendritic cells are present in the outer layers of the skin, where these phagocytic cells can attack invaders of the epidermis. Finally, a wide variety of normal skin microbiota have adapted to the adverse conditions of the skin and compete with potential invaders for nutrients and space. • What do we mean by axenic systems of the body. • A womb is an axenic environment, sterile from microbes. • CNS is an Axenic environment • Muscle, bones, csf (brain), blood Diphtheroids a Gram-positive pleomorphic bacteria commonly found on the skin. • Essay question the skin structure and function The skin protects us from microbes and the elements, helps regulate body temperature, waterproof barrier and permits the sensations of touch, heat, and cold. Smallpox is the first human disease to be eradicated • Immunization with cowpox provides against smallpox Spreading black necrosis, swelling, pain and froth or bubble characteristics of Gas gangrene Clostridium species Dermatophytoses-ringworm (Cell-mediated immune responses damage deeper tissues) • Dermatophytes colonize skin, nails, and hair • Use keratin as nutrient source Sporotrichosis (Caused by Sporothrix schenckii) • Occurs most often in gardeners and farmers Cytomegalovirus Disease teratogenic virus