This site is 100% ad supported. Please add an exception to adblock for this site.

MircoBio 351 final


undefined, object
copy deck
– groups of cells from same species/strain - Methanobacterium)
– populations that perform the same metabolic function in the ecosystem (e.g. Methanogenesis)
– the interactions of guilds (e.g. Freshwater anaerobic communities)
– communities plus macroscopic organisms plus environment
– something that causes harm
– diseases of animals that can be transmitted to humans
Incubation period
– the period after pathogen entry but before signs and symptoms appear
Prodromal stage
– onset of signs and symptoms but not yet clear enough for diagnosis
Period of Illness
– the period that the disease is most severe and has characteristic signs and symptoms
Period of decline
– period in which convalescence signs and symptoms begin to disappear
– class of proteins produced by pathogens that have a deleterious effect o the host, a toxin released extracellularly. Examples: Neurotoxins – botulinum toxin, tetanus or Enterotoxins – GI tract, cholera, shiga toxin, or Cytotoxins – act on the cells (blood)
– A toxin released from the cell; bound to the cell surface or intracellular, LPS or components, causes physiological reaction - reaction to a bacteria – the bodies response to infections – produced by the body in response to an infection.
What is syntrophy?
A process in which two or more organisms cooperate in the degradation of some compound. For the breakdown of a typical polysaccharide such as cellulose, for example the process begins with celluloytic bacteria, which cleave the high molecular-weight cellulose molecule into cellobiose (glucose-glucose) and into free glucose. Glucose is then fermented by primary fermenters into a variety of fermentation products with acetate, propionate, butyrate, succinate, alcohols, H2, and CO2 being the major products. Obligate metabolic interactions. Interspecies H2 transfer – fermentative bacteria to H2 utilizers (Methanogens). No free H2 to measure – very tight coupling. Example: Fermentation of ethanol to methane and acetate by syntrophic association of an ethanol-oxidizing bacterium, in this case a Methanogen.
How are microenvironements different from macroenvironments?
Scale - microenvironments can be very different from macroenvironment
Eg. Of an very heterogenous environment - soil
Nutrients (resources) and growth rates correlated but very different from batch culture.
Competition and co-operation
Limiting resources force competition
Ecosystem cycles force co-operation (eg. Nitrosifying and nitrifying bacteria convert NH4 to
No2 to No3 (ammonia oxidation) one cannot exist without the other.
What are food intoxications?
Toxin is ingested and causes disease
Streptococcus sp. -
Streptococcal diseases Strep throat, scarlet fever, pneumonia, etc.; treated with penicillin, cephalosporin, sulfonamide combination, or erythromycin; no available vaccines except one for streptococcal pneumonia; most streptococcal diseases are caused by varieties of Streptococcus pyogenes
– Gonorrhoeae and Meningitidis
Syphilis, Yaws and Pinta
occurs in utero is termed congenital syphilis. About 50% of such fetuses abort or are stillborn. Of those surviving birth, two scenarios are observed: the "early" form shows symptoms that are apparent at birth; in the "late" form, infants appear normal until they are about 2 years old and only then display the traits known as "Hutchinson's triad,” which include interstitial keratitis, notched incisors and eighth nerve deafness.
Caused by T. pertenue, this disease occurs in tropical Africa, S. America, India, Indonesia and the Pacific Isles (equatorial regions). Symptoms involve the occurrence of a painless papule called the "Mother yaw" as the primary stage. Following healing and complete dissemination of the organisms, many papules return after 1-12 months and occur on the face and moist body areas.
Caused by T. carateum, this disease occurs only in tropical Central and South America. It is characterized by a painless papule (primary) followed 2-18 months later by secondary papules on the hands, feet and scalp. These lesions heal slowly after treatment (unlike syphilis, yaws).
Vibrio cholerae
- Cholera
Campylobacter jejuni –
Campylobacteriosis often known as campylobacter enteritis or gastroenteritis
– Samonellosis, They cause gastroenteritis and some types can cause enteric fever (typhoid).
E. coli O157:H7
infection often causes severe bloody diarrhea and abdominal cramps; sometimes the infection causes nonbloody diarrhea or no symptoms. Usually little or no fever is present, and the illness resolves in 5 to 10 days. In some persons, particularly children under 5 years of age and the elderly, the infection can also cause a complication called hemolytic uremic syndrome, in which the red blood cells are destroyed and the kidneys fail. About 2%-7% of infections lead to this complication. In the United States, hemolytic uremic syndrome is the principal cause of acute kidney failure in children, and most cases of hemolytic uremic syndrome are caused by E. coli O157:H7.
Staphylococcus aureus
- staphylococcal food poisoning
Clostridium butulinum
– Botulism - foodborne botulism; although, wound botulism, infant botulism, and adult botulism
Borrelia sp.
- Lyme disease
Yersinia Pestis
- is responsible for the plague
- epidemic typhus, endemic typhus, spotted fever, trench fever, Q fever
Influenza B
- Influenza B virus usually causes a minor illness, but it does have the potential to cause more severe disease in older persons.
Hepatitis A,B,C,D,G
- Hepatitis is any inflammation of the liver; currently nine viruses are recognized as causing hepatitis; some have not been well characterized
Hepatitis B (serum hepatitis) is transmitted by blood transfusions, contaminated
equipment, unsterile needles, or any body secretion; also transplacental transmission to
fetus occurs. Most cases are asymptomatic. Symptomatic cases involve fever, appetite loss, and fatigue. Death can result from liver cirrhosis or HBV-related liver cancer
Hepatitis C is spread by intimate contact with virus-contaminated blood, in utero from
mother to fetus, by the fecal-oral route, or through organ transplants; disease is milder
than hepatitis B with no jaundice. Hepatitis D is caused by hepatitis D virus (HDV) formally called the delta agent, which only causes disease if the individual is co-infected with hepatitis B virus; co-infection may lead to a more serious acute or chronic infection than that normally seen with HBV alone. Treatment is supportive, to allow the liver damage to resolve and the liver to repair itself, and the use of the hepatitis B vaccine. Recently, hepatitis F and hepatitis G have been identified and are currently being
What are opportunistic pathogens?
These are diseases that are commonly found in the environment and cause disease only in individuals whose defenses are somehow debilitated
What are Nosocomial infections?
Hospital acquired infections.
What are some common nosocomial infections? Urinary tract infections, Septicemia (bloodstream infections), Respiratory, and burn/wounds
What is Septicemia?
Septicemia is the presence of bacteria in the blood (bacteremia) and is often associated with severe disease.
Disease state caused by the presence in the blood of bacterial toxins or other harmful substances.
Name some virulence factors. A number of pathogen-produced extracellular proteins aid in the establishment and maintenance of disease. These are called virulence factors.
1.Streptococci, staphylococci produce HYALURONIDASE that promotes the spreading of the organism by breaking down hyaluronic acid they also produce a vast array of PROTEASES, NUCLEASES, AND LIPASES that serve to depolymerize host proteins, nucleic acids, and lipids. 2.Fibrin Clots – are often formed at the site of microbial invasion by the host, to isolate the pathogens. Some organisms are able to produce fibrinolytic enzymes to dissolve these clots and allow the pathogen to spread one such is Streptokinase produced by streptococcus pyogenes. Another variety of Fibrin Clot mechanisms wants to keep the organism (pathogen) localized and protected so it helps the clotting, one such is Coagulase, produced by staphylococcus aureus.
What is the difference between Exotoxins and Endotoxins?
Exotoxins are a diverse group of soluble proteins released into the surrounding tissue by living bacterial cells. Exotoxins have specific reaction sites in the host; e.g., tetanus and botulinum exotoxins affect nerve tissue, and streptococcal toxins attack vascular tissue. Plants and animals also produce protein toxins. Some, such as cobra venom, are enzymes that destroy substances in host tissue. Endotoxins are polysaccharide and phospholipid substances found in the cell walls of bacteria that are freed when the cells die and break up. The pathologic effects of endotoxins, similar for all bacterial sources, include fever, shock, and intestinal hemorrhage. In sufficiently low doses, toxins stimulate the production of antibodies, or antitoxins, in the host, and toxins of a specific bacterial species have been injected to elicit formation of antibodies against the disease caused by the bacteria. Toxoids are protein toxins that have been heated or chemically treated to deprive them of their toxicity but not of the ability to induce the formation of antibodies.
Name three specific exotoxins and the organisms that produce them.
Anthrax toxin (Bacillus anthracis)
Cholera toxin (Vibrio cholerae)
Shiga toxin (Shigella dysenteriae)
What is PCR?
Polymerase chain reaction – a method used to amplify a specific DNA sequence in vitro by repeated cycles of synthesis using specific primers and DNA polymerase. How is it used to identify and study microbes? In microbial studies it is used for identification usually by 16s DNA.
What is an epidemic?
A sudden increase in frequency above the endemic level or normal level of occurrence
A worldwide epidemic, a long-term increase in frequency in a large (usually worldwide) population
An epidemic-like increase in frequency, but in a very limited (local) segment of the population, can often be traced to a single source
What does endemic mean?
Disease is constantly present, usually at a low level, in a particular area. Endemic disease maintains a relatively steady low-level frequency at a moderately regular interval
What is Morbidity?
Morbidity the number of new cases in a specific time period per unit of population
What is mortality?
Mortality number of deaths from a disease per number of cases of the disease
Define a common-source epidemic.
Common-source epidemic characterized by a sharp rise to a peak, and then a rapid but not as pronounced decline in the number of cases; usually results from exposure of all infected individuals to a single common, contaminated source, such as food or water
Define a propagated epidemic.
Person to Person - Propagated epidemic characterized by a gradual increase and then a gradual decline in the number of cases; usually results from the introduction of one infected individual into a population, who then infects others; these in turn infect more, until an unusually large number of individuals within the population are infected, example sexually transmitted diseases
What is herd immunity?
Herd immunity the resistance of a population to infection and to the spread of an infectious organism because of the immunity of a large percentage of the population (usually due to vaccinations); this limits the effective contact between infective and susceptible individuals
What is a reservoir of infection?
Reservoir of infection, a constant source of infectious disease. People, animals, and plants may be reservoirs of infection
What is a vector in infectious disease transmission?
The route through which the organism infects humans, malaria – the vector is a mosquito, usually animal in nature, a source can be the same as a vector but sources are usually non animal in nature – water, food, etc.
What are Sequelae?
Symptoms or whole new diseases that result from an original infection (occur after original infection has cleared)
In viral evolution, what is Antigenic shift?
A major change in viral proteins (antigens) due to a gene reassortment. This is why we need a new flu immunization each year. Antigenic shift is an abrupt, major change in the influenza A viruses, resulting in new hemagglutinin and/or new hemagglutinin and neuraminidase proteins in influenza viruses that infect humans. Shift results in a new influenza A subtype. When shift happens, most people have little or no protection against the new virus. While influenza viruses are changing by antigenic drift all the time, antigenic shift happens only occasionally. Type A viruses undergo both kinds of changes; influenza type B viruses change only by the more gradual process of antigenic drift.
Antigenic drift?
A minor change in viral proteins (antigens) due to gene mutation. These are small changes in the virus that happen continually over time. Antigenic drift produces new virus strains that may not be recognized by the bodyÂ’s immune system. This process works as follows: a person infected with a particular flu virus strain develops antibody against that virus. As newer virus strains appear, the antibodies against the older strains no longer recognize the "newer" virus, and reinfection can occur. This is one of the main reasons why people can get the flu more than one time. In most years, one or two of the three virus strains in the influenza vaccine are updated to keep up with the changes in the circulating flu viruses. So, people who want to be protected from flu need to get a flu shot every year.
Describe, in detail, at least two respiratory infectious diseases and their causative agents.
Mumps- Spreads in saliva and respiratory droplets, can be serious in post pubescent male (infects testes and causes sterility) MMR vaccine is used for prevention

Measles- (rubeola) skin disease with respiratory spread; infection confers permanent immunity; vaccine is used for prevention; serious outbreaks are still reported in North America and Europe, especially among college students, lack of herd immunity
Describe, in detail, at least two sexually transmitted infectious diseases and their
causative agents.
Neisseria Gonorrhoeae - Gonorrhea -
Treponema pallidum - Syphilis -
Neisseria Gonorrhoeae - Gonorrhea -
Sexually transmitted disease of the genitourinary tract, eye, rectum, and throat
Invades mucosal cells, causes inflammation and formation of pus
MaleÂ’s urethral discharge; painful, burning urination, Females frequently asymptomatic; some vaginal discharge; may lead to pelvic inflammatory disease (PID)Infection, if disseminated through the bloodstream can involve other organs
Birth through infected vagina can result in neonatal eye infections (ophthalmia neonatorum, or conjunctivitis of the newborn) leading to possible blindness. Diagnosis is by culture of the organism and/or use of a DNA probe
Treponema pallidum - Syphilis - Syphilis Treponema pallidum
Sexually transmitted or congenitally acquired in utero. Disease progresses in stages Primary stage lesion (chancre) at infection site that can transmit organism during sexual intercourse. Secondary stage skin rash and other, more general symptoms. Latent stage not communicable after two to four years except possibly congenitally. Tertiary stage degenerative lesions (gummas) in the skin, bone, and nervous system. Diagnosed by clinical history, microscopic examination, and serology
Treatment penicillin in early stages, tertiary stage is highly resistant to treatment Immunity is incomplete
Describe, in detail, at least two food/water-borne infectious diseases and their causative
Botulism - Botulism Clostridium botulinum
Salmonellosis - Salmonellosis Salmonella typhimurium
Botulism - Botulism Clostridium botulinum
Food toxication (poisoning). Frequently caused by canned foods that contain endospores, which germinate and
produce an exotoxin (neurotoxin)
Can cause death by respiratory or cardiac failure. Diagnosis is by hemagglutination testing or toxigenicity testing in animals using the patient=s serum, stools, or vomitus
Treatment is supportive; also antitoxin administration. Control involves safe food processing practices in the food industry and in home canning;
also not feeding honey to babies under one year of age helps prevents infant botulism
Salmonellosis - Salmonellosis Salmonella typhimurium and others
Food-borne, particularly in poultry, eggs, and egg products; also in contaminated water. Food infection (bacteria must multiply and invade the intestinal mucosa). Enterotoxin and cytotoxin destroy intestinal epithelial cells. Causes abdominal pain, cramps, diarrhea, and fever. Fluid loss can be a problem, particularly for children and elderly people. Treatment is fluid and electrolyte replacement
Controlled with good food preparation practices
Describe, in detail, at least two arthropod-borne infectious diseases and their causative
Lyme disease – caused by Borrelia Burgdorferi, B. garinii and B. afzelii

Plaque – caused by Yersinia pestis
Lyme disease – caused by Borrelia Burgdorferi, B. garinii and B. afzelii,
Tick borne, with deer, mice, or the wood rat as the natural reservoir
Symptoms – localized skin rash or circle, flu like symptoms, accompanied by fever, and this is a general malaise, which is reoccurring
Disease can progress to include heart inflammation, arthritis and neurological symptoms. Years later, it can cause symptoms resembling AlzheimerÂ’s disease and multiple sclerosis with behavioral changes as well. Laboratory diagnosis is by isolation of the spirochete, PCR to detect DNA in the urine, or serological testing (ELISA or Western Blot)
Treatment, antibiotics (Penicillin or tetracycline) in the early stages.
Plaque – caused by Yersinia pestis,
vector fleas which are dependent on the rodent population (rats) Approx. 25 cases per year in the US. Bacteria survive and proliferate inside phagocytic cells, Symptoms include subcutaneous hemorrhages, fever, and enlarged lymph nodes. Mortality rate is 50-70% if untreated, treatment, streptomycin or tetracycline, if untreated it may invade the lungs (pneumonic plague), resulting in 100% mortality if unrecognized within 12-24 hours. A vaccine is available for people at high risk.

Deck Info