GMU Microbiology Exam 3 Study Guide

Pathology

Study of disease. It deals with Etiology, Pathogenesis, and the effect of disease on the body.

Etiology

Study of the cause of disease

Pathogenesis

Manner by which a disease develops

Infection

Presence of a pathogenic microbe in the body

Disease

This is present when tissue damage occurs

Normal flora

Permanent bacterial residents that generally don't cause disease

Transient flora

Bacteria that are present only for a short time

Symbiosis

Relationship between normal microbiota and the host

Bacteriocins

Antimicrobial peptides

Commensalism

System where one organism benefits and the other is unaffected

Mutualism

System where both organisms benefit

Parasitism

System where one organism benefits at the expense of the other (any successful pathogen)

Opportunistic

A pathogen that only causes disease when the opportunity arises. Ex: Staph. Aureus can cause toxic shock syndrome.

Synergism

The effect of 2 organism acting together is greater than the effect of either one acting alone Ex: Mycoplasma fermentans & HIV-if 1 cell is infected by both, the cell will die much faster then when infected by just one or the other alone.

Symptom

A change in body function that is felt by a patient as a result of disease. Nonmeasurable.

Sign

A change in a body that can be measured or observed as a result of disease. Ex: fever or swelling

Syndrome

A specific group of signs and symptoms that accompany a disease

Communicable disease

A disease that is spread from one host to another (contagious)

Noncommunicable disease

A disease that is not transmitted from one host to another. Ex: Tetanus

Incidence

Fraction of a population that contracts a disease during a specific time

Prevalence

Fraction of a population having a specific disease at a given time

Sporadic disease

Disease that occurs rarely in a population, no prevalence

Endemic

Disease constantly present in a population. Usually person to person transmittance. Ex: Neisseria gonorrhoeae

Epidemic

Disease acquired by many hosts in a given area in a short time. Ex: Influenza

Pandemic

Worldwide epidemic

Sporadic

Localized occurrences. Localized/single reservoir. Ex: Clostridium botulinum

Acute

Disease where symptoms develop rapidly. Ex: flu

Chronic

Disease that develops slowly. Ex: Tuberculosis, AIDS, and leprosy

Asymptomatic

(subclinical) Disease where signs or symptoms aren't noticable or tolerated. Causative agent active but no pathology.

Latent

Diease with a period of no symptoms when the causative agent is inactive

Local infection

Pathogens are limited to a small area of the body. Ex: boil

Systemic infection

Infection throughout the body. Ex: chicken pox

Focal infection

Multiple but defined areas of infection. Ex: Tuberculosis

Sepsis

Toxic inflammatory condition arising from the spread of microbes of their toxins, from a focus of infection

Bacteremia

Bacteria in the blood

Toxemia

Presence of toxins in the blood

Viremia

Presence of viruses in the blood

Primary

____ infection: Acute infection that causes the initial illness.

Secondary

_____ infection: Infection after a primary infection, frequently an opportunistic pathogen

Predisposing factors

-Male/female anatomical differences

-Inherited traits, such as the sickle cell gene

-Climate and weather

-Fatigue/stress

-Age

-Lifestyle

-Chemotherapy

-Occupational

Disease development

1. Incubation-Time between initial infection and first signs/symptoms

2. Prodomal-Mild symptoms

3. Invasive (period of illness)-Major symptoms evident

4. Period of Decline-Lessoning of symptoms, acquired immune responce active, and increased secondary infection risk

5. Convalescent Period-No disease symptoms, strong immune response, and host recovery.

Reservoir

Continual source of the disease causing organisms, it can be living or inanimate

Direct

____ contact: Requires close association between infected and susceptible host

Indirect

____ contact: Spread by fomites (nonliving). Ex: Drinking glasses, eating utensils, and syringes

Droplet

____ contact: Transmission via airborne droplets. Ex: Coughing, talking, and sneezing.

Vehicle

-Transmission by an inanimate reservoir

-Transmission by water

-Transmission by food

-Transmission by air

Vectors

Arthopods (especially fleas, ticks, and mosquitos) that transmit disease

Mechanical

_____ transmission: Arthopod that carries the pathogen on its body or secretes it in feces.

Biological

_____ transmission: Pathogen that reproduces inside the vector and then that vector bites someone and infects them.

Nosocomical

_____ infections: Infections acquired as a result of a hospital stay. 5-15% of patients get these.

Epidemiology

Study of where and when disease occur

Morbidity

Incidence of a specific notifiable disease

Mortality

Deaths from notifiable disease

Morbidity rate

Number of people affected in relation to the total population in a given time period

Mortality rate

Number of deaths from a disease in relation to the population in a given time

Types of Epidemiology

-Descriptive

-Analytical

-Experimental

Descriptive

_____ epidemiology: Collection and analysis of data. Ex: John Snow

Analytical

_____ epidemiology: Comparison of a diseased group and a healthy group. Ex: Nightingale

Experimental

_____ epidemiology: Controlled experiments. Ex: Semmelweis

Case reporting

When health care workers report specified diseases to local, state, and national offices.

Nationally notifiable diseases

Diseases that physicians are required to report

Robert Whittaker

Who created the 5-kingdom system (Monera, Protista, Fungi, Animals, and Plants)?

Carl Woese

Who developed the 3-domain system in 1978?

Molecular phylogeny

Analyzing hereditary molecular differences, mainly in DNA sequences, to gain information on an organism's evolutionary relationships.

PCR

Genetic method for identifying prokaryotes

Serology

-Method for identifying prokaryotes.

-Measures immunoglubulins (antibodies) or cytokine production in a patient against a microbial antigen

Proteobacteria

-Mostly gram negative, chemoheterotropic

-Named after the Greek god Proteus who could shapeshift

-Classes: Alpha, Beta, Gamma, Delta, Epsilon

Alpha

___ Proteobacteria:

-Can grow in low levels of nutrients

-Some have stalks or buds called Prosthecae

-Includes some agriculturally important organisms.

Azospirillum

(genus) Found in soil. Fixes atmospheric nitrogen.

Rickettsia

(rod-shaped) Transmitted to humans by insects and ticks

-______ rickettsii causes Rocky Mountain Spotted Fever which is tramsitted by "dog ticks"

-______ typhi causes Typhus which is transmitted by lice.

-Obligate intracellular parasite

Caulobacter

_____ divides so one cell has a stalk and the other has flagellum and moves to a new location then becomes a stalked cell. The stalk anchors the cell.

Rhizobium

Fixes atmospheric nitrogen into ammonia which other plants can use.

Agrobacterium

_______ tumefaciens-A plant pathogen that causes crown gall. The bacteria inserts a DNA plasmid into the cells of the plant host.

Nitrobacter

Oxidizes NO2 to NO3

Wolbachia

Organism with a strange symbiosis that influences insect behavior.

Beta

___ Proteobacteria:

-Uses nutrients (such as hydrogen gas, ammonia, and methane) that diffuse away from areas of anaerobic decomposition of organic matter.

Examples of Beta Proteobacteria

~Thiobacillus-Sulfur oxidizing.

~Neissera-Nessieria gonorrhoeae causes Gonorrhea (gram-negative diplococci)

~Nitrosomonas-Oxidizes NH4 to NO2

Gamma

____ Proteobacteria:

-Orders: Vibrionales (facultatively anaerobic rods). Ex: Vibrio cholerae causes Cholera

-Pseudomonadales (gram negative aerobic rods or cocci). Ex: Pseudomonas Aeruginosa can cause pneumonia and nosocomial infections.

-Enterobacteriales (Facultatively anaerobic rods that inhabit intestinal tract like E. coli and Salmonella)

-Yersinia pestis caused Bubonic Plague

Delta

___ Proteobacteria: Predatory bacteria that prey on other bacteria.

~Bdellovibrio-Attaches to a gram negative bacterium and passed through the outer membrane and replicated in the periplasm.

Epsilon

____ Proteobacteria: Helical or vibrioid shaped bacteria that can cause intestinal disease (Campylobacter jejuni) or peptic ulcers and potentially gastric cancer (Helicobacter pylori)

Nonproteobacteria

(and Gram negative bacteria)

-Second phylum in Domain Bacteria

-Not closely related to Proteobacteria

-Many physiologically distinct groups like Cyanobacteria (blue-green algae that undergoes photosynthesis that has many forms and is oxygenic)

Gram-positive bacteria

-Divided into to groups: Firmicutes (Low G/C ratio) and Actinobacteria (High G/C ratio)

Firmacutes

(gram-positive)

-Clostridiales (Clostridium and Epulopisicum)

-Bacillales

-Lactobacillales

-Mycoplasmatales

Clostridium

Obligate anaerobes and spore formers

--C. botulinum causes botulism

--C. tetani causes tetanus

Bacillales

Facultative anaerobes. Spore formers.

~Bacillus anthracis-causes anthrax

~Staph. Aureus-A ubiquitous bacteria on human skin. Can be an opportunistic pathogen. Causes food poisoning, toxic shock, and surgical infections.

Lactobacillales

~Lactobacillus-Lactic acid bacterium

~Streptococcus-Lactic acid bacterium. A common pathogen. Causes strep throat, dental cavities, scarlet fever and rheumatic fever.

Mycoplasmatales

~Mycoplasma

-M. Pneumoniae causes pneumonia

Actinobacteria

(gram-positive)

-Mycobacterium

-Corynebacterium

-Propionibacterium

-Streptomyces

Mycobacterium

Aerobic rods ("acid fast")

-M. tuberculosis causes Tuberculosis

-M. leprae causes leprosy

Corynebacterium

-C. diptheria causes diptheria

Propionibacterium

-P. acnes causes acne

Streptomyces

-Replicate by asexual spores like fungi

-Filamentous growth

-FOund in soil--Major Antibiotic Producers-- Aerobic--Gives soil its characteristic scent.

Chlamydiae

-Unusual life cycle

-C. trachomatis causes blindness and is a sexually transmitted disease

-Treated with antibiotics

Chlamydiae Life Cycle

1. Bacterium's infectious form, elementary body, attaches to host cell.

2. Host cell phagocytizes the elementary body and houses it in a vacuole.

3. Elementary body reorganizes and forms reticulate body.

4. Reticulate body divides successfully, producing multiple reticulate bodies.

5. Reticulate bodies convert back to elementary bodies and are released from the cell.

Spirochaetes

-Helical rod-shaped organisms

-Axial filament movement

-Found in contaminated water, sewage, soil, decaying matter, and the mouths of animals.

Spirochaete pathogens

-Treponema palladium=Syphilis

-Borrelia burgdorferi=Lyme disease

-Leptospiraspecies= Diseases in dogs, rats, and swine

Bacterioidetes

Anaerobic bacteria found in human intestines, potentially the most prevalent intestinal microbe

Fusobacterium

Found in the mouth and may be involved in dental diseases.

Groups of Archaeans

1. Halophiles

2. Methanogens

3. Thermophiles

Fungal characteristics

-Uses aerobic respiration or fermentation

-Optimum pH for growth is ~5

-More resistant to high osmotic pressure than bacteria. Can grow in high sugar or salt concentration.

-Can grow in low moisture

-Needs less nitrogen than bacteria

-Can metabolize complex carbohydrates