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Micro first exam
Dr. Mittak's Microbiology 1st midterm
| Question | Answer |
|---|---|
| Why is microbiology more relevant than ever in today's world? | Infectious diseases are a leading health related issue, elderly population is increasing. New infectious diseases continue to emerge and be identified. |
| What's the difference between infectious and contagious? | Infectious: Host is infected (microbe makes ill) Contagious: Can infect others |
| What parts of our daily lives are affected by microbiology and infectious disease? | 1. air we breathe 2. food we eat 3. hospitals where get tx of illness and injury 4. natural disaster that can occur w/o warning |
| Why are diseases once thought to be controlled reappearing? | 1. Increased resistance to antibiotics 2. New diseases emerging and organisms thought harmless have been discovered to cause disease in some circumstances 3. Bioterrorism is becoming a fact |
| What is a pathogen? | A microorganism that causes an infection |
| The potential of a pathogen to cause disease is referred to as its degree of ___________ | virulence |
| Pathogens are characterized by their | Degree of virulence |
| Many bacteria and some fungi are part of _____________________ of the body. | normal microbial flora |
| Normal flora naturally colonize the _____ and _______ | skin and mucosal surfaces (usually harmless) |
| Some members of normal flora provide products and services to the body. When these organisms become pathogenic they are termed _________________ | Opportunistic pathogens (mild degree of virulence) |
| Highly virulent pathogens are always associated with __________ | disease |
| Pathogens can be looked at from what 3 perspectives? | 1. Epidemiology 2. Pathogenesis 3. Host defenses |
| What is the study of epidemiology? | Factors determining the frequency and distribution of disease |
| What are the 5 requirements of infection in epidemiology? | 1. Entry (get in) 2. Establishment (stay in) 3. Defeat the host defenses 4. Damage the host 5. Be transmissible |
| What are 4 transmission mechanisms pathogens use? | 1. Air (droplet transmission) 2. Food or water 3. Insect vectors 4. person-to-person contact |
| Pathogens can also be classified according to their __________ | geographic distribution. Some worldwide others restricted to certain geographical areas |
| Providing the best care for infected individuals and protection of others involves a clear understanding of __________ | the 5 requirements for infection. |
| How does knowing how an organism gains entry and how it spreads vital to care for the infected? | Implementation of strategies to limit spread. Understanding the spread of the disease |
| What are 4 factors that can cause an epidemic? | 1. poor socioeconomic conditions 2. ignorance of how infections occur 3. poor hygiene 4. natural disasters |
| Virulence factors are required for a pathogen to do what 3 things? | 1. persist in the patient 2. cause disease 3. escape or defeat host defenses |
| What are 2 types of host defenses? | 1. innate host defenses such as skin, eyelashes, etc. 2. specific host defenses such as B-cell memory and the immune system |
| What 2 things can bacterial pathogens do? | 1. produce digestive enzymes 2. produce toxins |
| Viral pathogens can _________ | kill the host cells. |
| Damage associated with an infection can be due to ___________ | overactive host defenses. |
| What type of infection can coughing be associated with? | respiratory infection |
| What type of infection can diarrhea be associated with? | digestive infection |
| What type of infection can nervous system dysfunction be associated with? | central nervous system (headache, walking/speaking trouble) |
| Infection can be characterized by a struggle between what? | pathogens vs. host defense |
| Infection depends on the success or failure of the ____________ | host defense. |
| Failure of the host defense = ? | infection |
| The innate immune response includes? (3) | 1. 1st line of defense 2. Nonspecific response 3. Variety of cellular and chemical factors |
| The adaptive immune response includes? (2) | 1. Lethal and specific response 2. Immune system memory |
| What are 3 methods pathogens have developed to defeat host defenses? | 1. Directly attack host defenses 2. Change their looks (form of camouflage) 3. Some hide (worms) |
| What are potent and successful tools to defeat infection? | Antibiotics Disinfectants and antiseptics Hygiene |
| What must antibiotics do since they are toxic chemicals? | Kill the disease-causing microorganisms but not harm the patient. |
| Treatments are easier for what type of infection? | bacterial |
| Why are few chemicals usable to defeat fungal infections? | fungal cells are very similar to human cells |
| Viruses are intracellular parasites so they must be attacked in what 2 ways? | 1. Before entry into a host cell 2. Infected host cells must be killed to kill the virus |
| The best treatment of disease is ___________ | prevention. |
| Prevention involves (2) | 1. public health measures 2. immunization |
| Public health measures include (5) | 1. Disinfection of water supplies 2. Monitoring of food supplies 3. Proper hygiene and sanitation 4. Proper waste removal and treatment 5. Insect and pest control |
| Immunization requires (5) | 1. Understanding of immune mechanisms 2. Design vaccines that successfully stimulate protection 3. Public health control of the immunization of children 4. Design and development of new vaccines 5. Ability to ensure the safety of new vaccines |
| Some microbes are beneficial to humans in what 3 ways? | 1. Recycle vital elements in soil 2. Convert elements in the environment into usable forms 3. Return carbon dioxide into the atmosphere |
| Microbes have been used for bioremediation since ____ | 1988. |
| Microbes for bioremediation and recycling can be used for (3) | 1. Recycle waste water during sewage treatment 2. Clean up and decontaminate toxic waste including chemical and oil spills 3. Production of enzymes used in cleaning solutions |
| Bacteria are extensively used to control ____ | pests. |
| Bacterial control of pests can be used in what 2 ways? | 1. Applied as a part of crop dusting 2. Genes can be engineered into the plants themselves |
| How are bacteria and viruses used for new technologies? (2) | 1. Bacteria can be engineered to produce drugs 2. Viruses can be used for gene therapy strategies |
| Understanding the requirements necessary for infection is critical to understanding _________ | treatment. |
| Pathogens use virulence factors as part of the infection process in what 2 ways? | 1. They allow pathogens to survive and thrive in the host. 2. They make harmless organisms dangerous and make dangerous organisms deadly. |
| What is a portal of entry? | Any point at which pathogens can enter. |
| What are 3 categories of portals of entry? | 1. Mucous membranes 2. Skin 3. Parenteral routes (i.e. insect bite, needle stick, road rash) |
| Mucous membranes are in direct contact with the ___________ ____________ | external environment. |
| Mucous membranes are found in what 3 areas of the body? | 1. Respiratory tract 2. Gastrointestinal tract 3. Genitourinary tract |
| What is the most favorable portal of entry to pathogens and why? | Respiratory tract b/c we have to breath continuously and pathogens can be found on droplets of moisture and dust particles. |
| Name 5 pathogens that use the respiratory tract. | 1. cold virus 2. bacteria and viruses that cause pneumonia 3. mycobacterium tuberculosis 4. influenza virus 5. smallpox virus |
| What is the 2nd most favorable portal of entry to pathogens and why? | The GI tract b/c we have to eat and drink regularly. It is the entry point for many pathogens even though it has many barriers. |
| Name 6 pathogens that use the GI tract. | 1. salmonella 2. shigella 3. escherichia (e. coli) 4. hepatitis virus 5. giardia (parasite, "beaver fever" 6. entamoeba (montezuma's revenge) |
| The GI tract is also an important _________ of ____. | portal of exit |
| What route of contamination is very important to the infection process? | fecal-oral route of contamination |
| What pathogen infects the stomach and duodenum and is a known risk factor for stomach and duodenal ulcers? | Helicobactor pylori |
| How does H. pylori survive the acidic environment of the stomach and where does it live? | It produces an alkaline halo(buffer) around itself and resides in the mucus that lines the stomach and duodenum. |
| UTIs are more common in ______ | women. |
| Genitourinary tract infections cause major problems in what 2 settings? | hospital and clinical |
| Diseases of the reproductive tract are part of what portal of entry? | Genitourinary tract |
| Name 4 pathogens that use the genitourinary tract. | 1. mycobacterium 2. chlamydia 3. herpes viruses 4. HIV |
| Many microorganisms reside on the ____ which must be _________ to allow entry. | skin; broken |
| Insect transfer is referred to as | vector transmission. |
| Pathogens use what to establish themselves in the cells or tissues? | structures like capsules (bulk) and fimbriae (bacteria velcro) |
| What types of adhesins can pathogens use to adhere to tissue? | glycolipids or glycoproteins |
| What is plaque? | A pellicle coats the tooth and bacteria adhere to it. 300 - 400 different types of bacteria will adhere to each other building a biofilm on the tooth. |
| Name a spirochete and what they do. | Treponema pallidum (causative agent of syphilis) corkscrew into tissues. 1 spirochete = infection |
| Increasing the number of pathogens can establish the ________ | infection in the host. |
| Some pathogens can double their numbers in as short as __________ | 20 minutes |
| What to the initials ID and LD stand for? | Infectious Dose and Lethal Dose |
| ID50 = Infectious dose 50% which means... | the number of organisms required for 50% of the host population to show signs of infection |
| LD50 = Lethal dose 50% which means... | the number of organisms required to kill 50% of a host population |
| What form of reproduction is seen in most bacteria and how does it work? | Binary fission A. one cell divides into 2 B. 2 divide to become 4... C. number of bacteria can increase very quickly |
| Virally infected cells will ____ which releases what? How does this affect the host cells? | lyse; millions of viral particles each particle can infect a new cell and each newly infected cell will produce millions of viral particles. |
| Name 2 ways pathogens can defeat host defenses. | 1. Passive defense: using built-in structures found on the pathogen cell 2. Active defense: attacking the host defenses |
| Name 2 types of passive defenses used by pathogens and how they work. | 1. Capsules: encases bacteria making it bigger and inhibiting phagocytosis 2. Cell walls: increase adherence to host cells and inhibit phagocytosis |
| How do M proteins and Mycolic acid use cell walls as passive defense? | M proteins found in strept cell walls increase adherence to cell walls and inhibit phagocytosis Mycolic acid is a waxy material found in mycobacterium species inhibit phagocytosis and entry of antibiotics |
| Active bacterial defenses involve the production of extracellular enzymes which can: (2) | 1. increase protection against host defenses 2. enable the spread of infection by attacking and killing host defensive cells |
| What do leukocidins do? | destroy WBCs |
| What do hemolysins do? | attack RBCs and WBCs |
| What does coagulase do? | causes formation of fibrin clots |
| What do hyaluronidase and collagenase do? | break down connective tissue and collagen |
| How do viruses and bacteria get inside a host cell to hide from the host defense? | Viruses are obligate intracellular parasites and easily enter host cells. Bacteria use host cell cytoskeleton (microtubules and microfilaments) to get in and move around the cell; they can also use cadherin to move into adjacent cells |
| Damage to the host can be divided into what 2 causes? | 1. damage that occurs b/c pathogens are present and active 2. damage that occurs b/c of host defense mechanisms |
| What is direct and indirect damage to a host committed by a pathogen? | Direct: is obvious, includes destruction of host cells or defenses is usually controlled by the host immune response Indirect: involves systemic infection as a result of a toxin produced by the pathogen |
| Bacterial toxins are (3) | 1. very poisonous 2. soluble in aqueous solutions (blood and lymph) 3. easily diffusible into blood and lymph which causes distal pathology |
| Bacterial toxins can produce what type of outcome in patients? | fatal |
| Bacterial toxins produce what symptoms? | fever, shock, diarrhea, cardiac and neurological trauma, destruction of blood vessels |
| Name the 2 types bacterial toxins | endotoxins exotoxins |
| Exotoxins are (3): | produced by and exported from certain pathogens and then enter host cells. they are among the most lethal substances known. usually enzymatic protein soluble in blood and lymph system. |
| Exotoxin functions (3): | rapidly diffuse into tissues where they inhibit metabolic function. produced to attack host defenses. many genes that code for toxins are carried on plasmids (ring of DNA) |
| Action of cytotoxins? | kill cells |
| Action of neurotoxins? | interfere with neurological signaling |
| Action of enterotoxins? | affect the lining of the digestive system |
| Anthrax is a ____________ produced by what? | cytotoxin; bacillus antracis (a gram-positive rod commonly found in pastures) |
| Anthrax is made up of 3 parts that are produced and assembled how? It increases ______________ in host cells. | produced seperately within the pathogen assembled outside the anthrax organims cell wall; vascular permeability |
| Diphtheria is a _____________ produced by _______. It is produced in _______ form, inhibits ________ in the host and a _______ molecule can kill a host cell. | cytotoxin; corynebacterium diphtheriae inactive; protein synthesis; single |
| Botulinum toxin is a _________ produced by _____________. There are __ forms of this toxin all inhibit the release of ________ which causes what? | neurotoxin; clostridium botulinum 7; Ach; disrupts neurological signaling of skeletal muscle and causes flaccid paralysis |
| Tetanus toxin is a ___________ produced by _________. It causes loss of ______________ which prevents and causes? | neurotoxin; clostridium tetani skeletal muscle control; prevents muscle relaxation and causes uncontrollable convulsive muscle contractions. Lock jaw is an early symptom |
| Vibrio toxin aka __________ is a ____________ produced by ________. Release of large amounts of __________ causes what? | cholera toxin; enterotoxin; vibrio cholerae. electrolytes; potentially lethal diarrhea and vomiting |
| Toxic shock syndrome is caused from a _________ from _____________. Causes excessive loss of _______ which can lead to _________ | enterotoxin; staphylococcus aureus electrolyte fluids; hypotensive shock (arrhythmia) |
| Endotoxins are part of ______________ and released on the _______ of the host and released in the form of _______. | Gram-negative cell walls; death; lipid A |
| Most exotoxins are gram-________ Most endotoxins are gram-__________ | positive negative |
| Symptoms from and endotoxin? | chills, fever, aches, muscle weakness, disseminated intravascular clotting |
| Viral host cell damage is referred to as a ____________ | Cytopathogenic effect (CPE) |
| 3 ways the cytopathogenic effect of viruses occurs? | 1. from viral overload 2. from cytocidal effects (killing of host cells 3. from noncytocidal effects (damage caused by host defense) |
| Viral cytopathology can be seen _____________. What inclusions can be seen in rabies infections? What is a term for giant cells? | microscopically negri bodies syncytia |
| The transmission of infection is the final requirement for a ____________________. | successful pathogen |
| 2 factors that affect the spread of infection | 1. reservoirs of infectious organisms - places where pathogens can grow and accumulate. 2. mechanisms of transmission - the various ways in which pathogens move from place to place. |
| Name 3 potential reservoirs of pathogens | 1. humans 2. other animals 3. nonliving reservoirs (water, air, surfaces) |
| Name 2 types of human reservoirs | 1. sick people - symptoms may be visible or have yet to develop 2. carriers of infections - infectious but don't show symptoms |
| Diseases transferred from animals to humans are called ___________. | zoonotic diseases |
| Zoonotic diseases are usually transmitted through ______________ with humans. They can also be indirectly transmitted by _______. | direct contact with humans vectors (mosquitoes, sand flies, etc.) |
| Nonliving reservoirs of infection include (3) | water, food, soil (water most dangerous) |
| Infections of nonliving reservoirs are seen in countries with (2) | poor sanitation and low levels of personal hygiene |
| Name 4 diseases transmitted through direct contact | 1. smallpox 2. staphylococcal infections 3. mononuclosis 4. sexually transmitted diseases |
| Indirect contact transmission takes place through what nonliving articles? | tissues, handkerchiefs, towels, bedding, contaminated needles |
| Nonliving intermediates that act as the agents of transmission by indirect contact are referred to as _______. | fomites - any surface capable of spreading disease |
| Droplet transmission is seen in the transfer of what type of disease? | respiratory (influenze, whooping cough) |
| Droplet transmission can occur how? | sneezing, coughing, laughing |
| Regions with poor sanitation practices can have high levels of ________ contamination in the water. | fecal |
| Soil pathogens can only enter the body how? | break in the skin |
| What are 3 mechanisms of pathogen transmission? | Contact Vehicle Vector |
| Name 3 types of contact transmission | Direct Indirect Droplet |
| The _________ the droplet the more dangerous it is as an agent of disease. | smaller (airborne longer) |
| Name 7 vehicle transmitters | air food water blood bodily fluids drugs IV fluids |
| What sort of things use air as a vehicle? | dust - can contain lots of pathogens microbial and fungal spores can use air to travel from host to host |
| Name some arthropods that transmit via vector transmission. | fleas, ticks, flies, lice, mosquitoes |
| name and define 2 types of vector transmission. | Mechanical vector transmission: pathogens on vector's body parts and passively brushed off onto host Biological transmission: pathogens are within the vector and transmission to the host is through a bite |
| Name 6 factors that affect disease transmission | age, gender, lifestyle, occupation, emotional state, climate |
| Name 9 portals of exit | saliva, sputum, respiratory droplets, blood, vaginal secretions, semen, urine and feces |
| What is immunocompetence? | The host's ability to mount a defense to a pathogen. |
| What does it mean to be compromised? | infected -> infectious |
| What situations can weaken immune defenses of a host? (5) | lifestyle, occupation, trauma, travel, aging |
| What groups of people are immunocompromised? (7) | People with AIDs and genetic immunodeficiency diseases People undergoing chemo and taking broad spectrum antibiotics Surgical, transplant and burn victims Premature, newborn infants Health care workers The elderly Patients on artificial ventilators |
| Define neutropenia | lower-than-normal numbers of neutrophils in the blood. |
| What is the most common cause of profound neutropenia and what types of infections are seen with it? | cytotoxic chemotherapy bacterial and fungal |
| How soon can one expect to see a bacterial or fungal infection when neutropenia is present? | Bacterial infections can be seen as soon as neutrophil levels start to drop. Fungal infections are usually seen after neutrophil levels have been low for a long amount of time. |
| To reduce infection in patients who have had organ-transplants the drugs required are __________ but these drugs can cause _________ (2) | broad spectrum antibiotics; antibiotic resistance and super infections |
| Burn victims are at risk of infections because? What infection is a particular problem in burn victims? | loss of large areas of the primary physical barrier to infection (skin); pseudomonas |
| What is a nosocomial infection? | Any infection acquired in the hospital or institutionalized care that isn't primary care. |
| Nosocomial infections are usually associated with or following? (2) | catheterization invasive tests and surgery |
| The most common pathogens that cause nosocomial infections are what? (4) | 1. escherichia coli 2. enterococcus species 3. staphylococcus aureus 4. pseudomonas aeruginosa |
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