Microbiology Final Exam-Key Terms

Epidemic typhus

(Louse-borne typhus) A disease caused by Rickettsia prowazekii, which grows in the intestinal tract of human body lice and flying squirrels in eastern United States. It is transmitted when the human scratches the wound, rubbing the fecal material into the bite left by the human body louse.

Lipase

A bacterial enzyme that acts with the oils and fats secreted by the sebaceous glands allowing bacteria to colonize in the skin.

Coagulase

A bacterial enzyme that causes blood to clot by converting fibrinogen into fibrin.

Hyaluronidase

A bacterial enzyme that penetrates the body's connective tissues, permitting the easy spread of infection throughout the body.

Tsetse fly

A blood-sucking fly found only in Africa that spreads trypanosomes causing African sleeping disease.

Trachoma

A chronic, contagious form of conjunctivitis that is one of the leading causes of blindness in the world.

diplobaccili

A double bacillus, two being linked end to to end with each other.

Malaria

A febrile disease of the blood characterized by chills and fever. It is caused by a protozoan and spread by mosquito bite.

Antigen

A foreign substance that stimulates the formation of antibodies that interact specifically with it.

Rickettsia

A genus of rod-shaped, gram-negative, pathogenic, intracellular parasitic microorganism.

Fungi

A group of often filamentous unicellular and multicellular organisms lacking chlorophyll and usually bearing spores.

Poliomyelitis

A highly contagious infectious disease of the spinal cord caused by the poliovirus.

Chlamydia

A large group of nonmotile, gram-negative, intracellular parasites.

Mechanical vector

A living organism or an object that is capable of transmitting infections by carrying the disease agent o its external body part or surface.

Pathogen

A microorganism capable of producing disease.

Bacteria

A prokaryotic one-celled microorganism of the kingdom Monera, existing as free-living organisms or as parasites, multiplying by binary fission and having a large range of biochemical properties.

Parrot fever

A respiratory disease caused by Chlamydia psittaci, which is a gram-negative, obligate intracellular rickettsia.

Prions

A small proteinaceous infectious particle that is resistant to most procedures that modify nucleic acids.

Mutualism

A symbiotic relationship in which two different species live in close association to the mutual benefit of each other.

Endospore

A thick-walled cell produced by a bacterium to enable it to survive unfavorable environmental conditions.

Coccus

A type of bacteria that is spherical or ovoid in form.

Dermatophytes

A wide variety of fungi that can infect the integumentary system.

Bactericides

Agents that destroy bacteria but not necessarily their spores.

Fungicides

Agents that destroy fungi and their spores.

Larvicides

Agents that destroy insect larvae.

Insecticides

Agents that destroy insects.

Viricides

Agents that destroy viruses.

Sporicides

Agents that kill bacterial and mold spores; act as sterilizing agents.

Rabies

An acute, neurotropic, infectious disease caused by the rhabdovirus known as the rabies virus.

Biological vectors

An animal vector in which the disease causing organism multiplies or develops within the animal prior to becoming infective for a susceptible individual.

Eschar

An anthrax lesion characterized by a central mass of necrotic tissue surrounded by inflammatory vesicles.

Mumps

An infectious disease of the parotid salivary glands caused by the mumps virus.

Mononucleosis

An infectious inflammatory disease caused by the Epstein-Barr virus.

Hepatitis

An inflammatory disorder of the liver caused by a virus, commonly hepatitis viruses A, B, and C. Hepatitis B is spread through the body fluid contact, and it can lead to either chronic liver disease or death.

Parasitism

An interactive relationship between two organisms in which one is harmed and other benefits.

Virus

An intracellular, infectious parasite, capable of replicating only in living cells.

Opportunists

An organism that exists as part of the normal flora but that can become pathogenic under certain conditions.

Baccillus

Any rod-shaped microorganism.

Diplococci

Any various spherical bacteria appearing in pairs.

Rickettsiology

Area of science that studies rickettsia.

Streptobacilli

Bacteria containing gram-negative rods that form a chainlike colony.

Mycoplasma

Bacteria of the mycoplasma genus that are found in humans, most having no cell wall; the smallest free-living organism presently known, being intermediate in size between viruses and bacteria.

Pyschrophiles

Bacteria that prefer cold, thriving at temperatures between 0 degrees Celsius and 25 degrees Celsius.

Mesophiles

Bacteria that prefer moderate temperatures and develop best at temperatures between 25 degrees Celsius and 40 degrees Celsius.

Thermophiles

Bacteria that thrive best at high temperatures, between 40 degrees Celsius and 70 degrees Celsius.

Creutzfeldt-Jacob disease

Believed to be caused by a prion, a progressive disease that causes spongiform- porous, like a sponge- degeneration of the brain.

Septicemia

Conditions characterized by the multiplication of bacteria in blood; commonly known as blood poisoning.

Attenuation

Dilution or weakening of the virulence of a microorganism, reducing or abolishing its pathogenicity.

Toxiemia

Distribution throughout the body of poisonous products of bacteria growing in a focal or local site, thus producing generalized symptoms.

Antibodies

Glycoprotein substances developed in response to and interacting specifically with an antigen; also known as immunoglobulins.

Staphylococci

Gram-positive , nonmotile bacteria that tend to aggregate in irregular, grapelike clusters.

Streptococci

Gram-positive spherically shaped bacteria that occur in chains.

Universal precautions

Guidelines designed to protect workers with occupational exposure to bloodborne pathogens.

Faculatative

Having the capacity to do something that is not compulsory; in particular, having the ability to live or adapt to certain conditions.

Buboes

Infected lymph nodes associated with bubonic plague or other diseases.

Flagella

Long, whiplike, filament-containing appendages that propel bacteria in liquid.

Antagonism

Mutual opposition or contrary action. The inhibition of one bacterium by another.

Protozoa

One-celled organisms by the kingdom Protista; most are unicellular although some are colonial.

Saprophytes

Organisms that only survive on dead and decaying organic matter.

Antisepsis

Preventing or inhibiting the growth of pathogenic microorganisms.

Sterilization

Process of completely removing or destroying all life-forms, endospores, or their products on or in a substance.

Virulence

Relative power and degree of pathogenicity possessed by organisms to produce disease.

Heterotrophic

Requiring complex organic food from a carbon source in order to grow and develop.

Microanerophilic

Requiring little free oxygen.

Drug-fast

Resistant, as in bacteria, to the action of a drug or drugs.

Protozoology

Science that deals with the study of protozoa.

Bacteriology

Science that studies bacteria

Autotrophic

Self-nourishing, capable of growing in the absence of organic compounds. Organisms that obtain carbon from carbon dioxide.

Germicides

Substances that destroy microorganisms but not necessarily their spores.

Resistance

The ability of an organism to defend itself against infection and disease; the sum total of body mechanisms that interpose barriers to the progress of invasion, multiplication of infectious agents, or damage by their toxic products.

Contamination

The act of introducing disease germs or infectious material into an area or substance.

Mycology

The branch of science concerned with the study of fungi.

Disinfection

The destruction of pathogenic agents by chemical or physical means directly applied to an inanimate object.

Synergism

The harmonious action of two microorganisms producing an effect that neither could produce alone.

Symbiosis

The living together in close association of different species.

Rocky Mountain spotted fever

The most severe rickettsial infection; it is caused by Rickettsia rickettsii.

Reservoir

The natural habitat of a disease-causing organism.

Host

The organism from which a microorganism obtains its nourishment.

Pathogenicity

The state of producing or being able to produce pathological changes and disease.

Morphology

The study of the size, shape, and arrangements of microorganisms.

Virology

The study of viruses and viral diseases.

Commensalism

The symbiotic relationship of two organisms of different species in which one organism gains some benefit such as protection or nourishment.