Microbiology Final Exam: principles of disease

What does CSF stand for and what type(s) of microbes would you find in the CSF of a healthy individual?

Cerebrospinal fluid

What is an etiologic agent?

causes disease in humans

What is commensalism? Is it a symbiotic or non-symbiotic relationship? Provide a microbiological example of commensalism.

commensalism-symbiotic: one party benefits, and the other party is unaffected example: S. epidermis feeds off of hands, doesn't affect us

Why should the lower respiratory tract be considered a relatively sterile environment in a healthy individual?

in healthy individuals microbes should NOT be able to "make it down that far"

What is the difference between an infection and a disease?

infection: invasion of colonization of the body by a pathogenic microorganism pathology: study of disease

What are endogenous infections?

infections caused by our normal flora

What are nosocomial infections?

infections that you "pick up" during a hospital stay

Define septicemia, bacteremia, toxemia and viremia.

septicemia: "blood poisoning" growth of a pathogenic microbes in the blood (non specific) bacteremia: bacteria in the blood toxemia: presence of a toxin in the blood viremia: presence of viruses in the blood

What is a sporadic disease, an endemic disease, an epidemic disease and a pandemic disease?

sporadic disease: only occurs occasionally endemic disease: is constantly in a population (steady frequency) epidemic disease: increasing in a population (rising frequency) pandemic disease: epidemic disease that occurs across continents (worldwide)

What is pathology the study of?

study of disease

With respect to microbiology, explain what symbiotic and non-symbiotic relationships are.

symbiotic: organisms live in close nutritional relationship that is required by at least one member for survival (relationship) non symbiotic: organisms co-habitat but NO relationship is required for survival

Define the terms symptom and sign with respect to disease.

symptom: subjective evidence like a sore throat=something the patient feels sign: objective evidence (e.g. swollen tonsils) something that someone else can see

What is synergism? Is it a symbiotic or non-symbiotic relationship? Provide a microbiological example of synergism.

synergism: all microbes cooperate and share nutrients. IF you remove one, the other can survive example: a mixed infection

What is one of the major sources of nosocomial infections?

urinary tract infection-catheters

What most pathogenic microbes probably thinks of us as.....

-nutrient rich -moist -stable pH -stabel temperature -lost of places to "hang out"

What are the three reservoirs of infection?

1. Human reservoirs 2. animal reservoirs 3. nonliving reservoirs

List the five ways a microbe can be transmitted from a reservoir of infection to a susceptible host.

1. direct contact 2. indirect contact 3. droplet 4. vehicle (food, water, air) 5. vectors (insects)

Describe the five periods that occur during the development of an infectious disease.

1. incubation period: time between initial infection and first signs or symptoms of disease. NO indication of disease. NOT contagious 2. Prodromal Period: time of early mild symptoms of the disease, generally not contagious. 3. Period of Illness: time when the disease is most severe and generally most contagious. Generally immune defenses kick in to high gear during this period to fight of pathogen. If disease not overcome death occurs. 4. Period of decline: signs and symptoms of disease is subside. Vulnerable to secondary infections at this time. Still may be contagious 5. Period of convalescence: body return to pre-disease state, recovery occurs. May still be contagious.

What three things are required for a nosocomial infection to occur?

1. microorganism 2. compromised host 3. chain of transmission

What areas of our body are considered to be relatively sterile?

1. nervous system 2. lower respiratory tract 3. cardiovascular system

Name the five types of human carriers and give an example of each.

1. passive carrier: health care worker 2. incubation carrier: HIV positive people, mono 3. convalescent carrier: influenza 4. chronic carrier: hepatitis 5. asymptomatic carrier: typhoid mary (spread salmonella)

Explain/describe Koch's postulates.

1. same organism must be found in ALL hosts with disease but NOT in health hosts 2. organism must be isolated from a disease host and grown in a pure culture 3. the cultured organism should cause the same disease when introduced into a healthy host 4. The sam organism must be isolated from the new diseased host and grown in a pure culture

Name the two most common nonliving reservoirs of infection.

1. soil 2. water

What areas of our body have normal microbiota?

1. upper respiratory tract 2. gastoinestinal tract 3. skin 4. urogenital tract

List several reasons why these postulates are not perfect and cannot be applied to the identification of all infectious etiologic agents.

1. what about an organism that cannot be cultured? 2. what about an opportunistic pathogen or host that is infected with the organism but has no signs of disease (asymptomatic?) 3. What about an organism that can cause several different disease conditions 4. What if the organism ONLY infects and causes disease in humans?

What period(s) during the development of an infectious disease will signs or symptoms of the illness be apparent?

2. prodromal period 3. period of illness

What period(s) during the development of an infectious disease may a person be considered contagious?

3. period of illness 4. period decline 5. period of convalescence

What does asymptomatic mean?

NO signs or symptoms or a disease but the patient is infected

What is an opportunistic pathogen?

a microorganism that can cause disease only when an individuals immune response is weak OR when it moves to a new location within the body e.coli from out intestines and could get somewhere else and infect

What is an acute disease, a chronic disease and a latent disease? Provide an example of each.

acute disease: develops rapidly but lasts a short time (e.g. cold) chronic disease: develops more slowly but will continue/persist over a long period of time (e.g. hepatitis) latent disease: remains inactive for a time then becomes active to produce the symptoms of the disease again (e.g. herpes)

Define the term zoonosis.

animal reservoir: disease that occurs primarily in animal but that can be transmitted to humans

What is antagonism? Is it a symbiotic or non-symbiotic relationship? Provide a microbiological example of antagonism.

antagonism: microbes compete for nutrients and if possible will inhibit or destroy competition not working together as a pair, one is plotting against another example: antibiotics produced by one type of microbe in order to outcompete the other

What impeded microbes from entering our nervous system and what three cell types make up this structural barrier?

blood-brain barrier: 1. endothelial cells 2. astrocytes 3. neurons

Explain the difference between horizontal and vertical transmission of a disease.

horizontal: person, animal, fomite, food, water, insect vertical: person (e.g. sperm, placenta)

What is the purpose of Koch's postulates?

ideas/steps to be used if a microorganism is the cause of disease (etological agent)

What is a local infection, a systemic infection and a focal infection?

local infection: remains limited to a relatively small area of the body (e.g. wart) systemic infection: microbes are spread to other parts of the body by the BLOOD or LYMPH (serious) (syphillis) focal infection: microbes from a local infection enter the blood or lymph and spread to other SPECIFIC parts of the body where they remain confined

Explain the difference between mechanical vector and biological vector transmission.

mechanical: transport microbe on parts of the bodies without being infected biological: transport microbes through its bite; however, the insect is also infected

Define the terms microbial pathogenesis and normal microbiota.

microbial pathogenesis: the characteristics/traits the microbe has that lead to disease normal microbiota: the normal bacterial cells in body

What is mutualism? Is it a symbiotic or non-symbiotic relationship? Provide a microbiological example of mutualism.

mutualism-symbiotic: both partners benefit. E. coli feeds off nutrients in large intestine, humans use E.coli makes VK used by our cells

Do we all have the same normal microbiota?

no

What is a fomite?

non living object

What is parasitism? Is it a symbiotic or non-symbiotic relationship? Provide a microbiological example of parasitism.

parasitism-non symbiotic: one party benefits, and the other party suffers HIV uses our cells to replicate to benefits, humans contract a terminal disease and suffered

Define the terms prevalence, incidence and mortality rate as they relate to infectious diseases.

prevalence: % of cases with respect to the entire population incidence: measure of # of NEW cases/total # of susceptible people over a specific period of time

What is a primary infection and a secondary infection?

primary infection: an acute infection that causes the initial illness (e.g. common cold) secondary infection: caused by an opportunistic pathogen after the primary infection has weakened the immune system (e.g. bacterial bronchitis)

What are probiotics and what might be considered the "ultimate" probiotic?

probiotics: live microbial cultures that are administered or ingested with the intent to exert a beneficial effect feces