Comps Microbiology Glossary

Allergy (Hypersensitivity)

an acquired, abnormal immune response to a substance (allergen) that does not normally cause a reaction.

Antagonism

mutual opposition or contrary action. The inhibition of one microorganism by another

Antibody

glycoprotein substance developed by the body in response to, and interacting specifically with, an antigen. Also known as immunoglobulin

Antigen

a foreign substance that stimulates the formation of antibodies that react specifically with it

Antisepsis

the prevention or inhibiting of the growth of causative microorganisms

Attenuation

dilution or weakening of virulence of a microorganism, reducing or abolishing pathogenicity

Autotrophic bacteria

self nourishing bacteria (can utilize CO2 as their only carbon source

Bacillus (pl. Bacilli)

rod shaped bacteria

Bacteremia

the presence of bacteria in the blood

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.

Bacterial colony

a visible group of bacteria growing on a solid medium, presumably arising from a single microorganism.

Bactericide

an agent that destroys bacteria but not necessarily their spores

Bacteriology

science that studies bacteria

Bacteriostatic

Inhibits bacteria growth

Binary fission

a method of asexual reproduction involving halving of the nucleus and cytoplasm of the cell followed by the development of each half into a new individual. (The most common type of reproduction in bacteria)

Biological Vector

an arthropod vector in which the disease-causing organism multiplies or develops within the arthropod prior to becoming infective for a susceptible individual

Capsule

the membrane that surrounds some bacterial cells; a loose gel-like structure that, in pathogenic bacteria, helps to protect against phagocytosis

Chlamydia

a large group of nonmotile, gram-negative intracellular parasites. (Chlamydia trachomatis causes the most common sexually transmitted disease – NGU)

Coccus (pl. Cocci)

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

Commensalism

the symbiotic relationship of two organisms of different species in which one gains some benefit such as protection or nourishment and the other is not harmed or benefited

Communicable

a disease that may be transmitted directly or indirectly from one individual to another

Consumption

another name (historical) for tuberculosis

Contamination

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

Coryza

causes the common cold (Rhinitis – inflammation of the nasal passages) – It affects the Respiratory System

Diplobacilli

a double bacillus, two being linked end to end. Morax-Axenfeld bacillus a cause of conjunctivitis is typical of this form

Diplococcus

a genus of bacteria that occur in pairs

Disinfectant

a chemical or physical agent that kills disease-causing microorganisms

Disinfection

the destruction of disease-causing microorganisms by chemical or physical means

Drug-fast

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

Endemic

disease that occurs continuously in a particular region but has low mortality

Endogenous infection

produced or arising from within a cell or organism

Endospores

a thick-walled spore within a bacterium (resistant to environments that kill growing cells and can remain dormant for hundreds of years).

Endotoxin

bacterial toxin confined within the cell wall of a bacterium freed only when the bacterium is broken down, found only in gram negative bacteria.

Epidemic

appearance of an infectious disease or condition that attacks many people at the same time in the same geographical area

Exogenous infections

originating outside an organ or part

Exotoxin

a toxin produced by a microorganism and excreted into its surrounding medium

Facultative

a bacteria having the capacity to do something that is not compulsory, in particular having the ability to live or adapt to certain conditions

Facultative anaerobe

an organism that prefers an oxygen environment but is capable of living and growing in its absence

Facultative aerobe

a microorganism that prefers an environment devoid of oxygen but has adapted so that it can live and grow in the presence of oxygen

Facultative saprophyte

prefers live organic matter as a source of nutrition but can adapt to the use of dead organic matter under certain conditions.

Focal infection

one in which the organisms are originally confined to one area but enter the blood or lymph vessel and spread to other parts of the body.

Fomite

any inanimate object to which infectious material adheres and can be transmitted

Fungicide

a substance that kills fungi

Fungus (pl. fungi)

a group of diverse and widespread unicellular and multicellular organisms, lacking chlorophyll, usually bearing spores and often filamentous

General infection

an infection that becomes systemic

Germicide

a substance that destroys microorganisms

Heterotrophic bacteria (other than self nourishing)

organisms that must obtain their nourishment from complex organic matter.

Hypochlorites (bleaches)

chlorine containing compounds.

Indigenous flora

synonymous with "normal flora" indicates the microbial population that lives with the host in a healthy condition

Infection

the entry, establishment and multiplication of pathogenic organisms within a host; the state or condition in which the body or a part of it is invaded by a pathogenic agent that under favorable conditions, multiplies and produces injurious effects

Insecticide

a substance that kills insects

Iodophors

a compound consisting of iodine combined with a carrier, such as polyvinylpyrrolidone, often used as a preoperative skin disinfectant

Larvacide

a substance that kills insect larva

Local infection

infection caused by germs lodging and multiplying at one point in a tissue and remaining there.

Maximum temperature

temperature above which bacterial growth will not take place

Mechanical vector

a living organism capable of transmitting infections by carrying the disease agent on its external body parts or surfaces.

Mesophile

bacteria that prefer moderate temperature and develop best at temperatures between 25C and 40 C

Microaerophilic

a microorganism that requires very little free oxygen

Microbiology

scientific study of microorganisms and their effect on other living organisms

Minimum temperature

temperature below which bacterial growth will not take place

Mixed infection

infection caused by two or more organisms

Mutualism

a relationship in which organisms of two different species live in close association to the mutual benefit of each other

Mycology

the branch of science concerned with the study of fungi

Mycoplasmas

bacteria of the Mycoplasma genus that are found in humans and have no cell wall; the smallest free-living organisms presently known being intermediate in size between viruses and bacteria

Non-Symbiotic

organisms that are free living and relationships are not required for survival

Opportunist

an organism that exists as part of the normal flora but may become pathogenic under certain conditions

Optimum temperature

temperature at which organisms grow best

Osmotic pressure

pressure that develops when two solutions of different concentrations are separated by a semipermeable membrane

Pandemic

a disease affecting the majority of the population of a large region or one that is epidemic at the same time in many different parts of the world.

Parasitism

an interactive relationship between two organisms in which one is harmed and the other benefits

Pathogenicity

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

Primary infection

the "first" infection that a host has after a period of health

Prion

small proteinaceous infectious agents (particles) which almost certainly do not have a nucleic acid genome and therefore resist inactivation by procedures that modify nucleic acids. Prion diseases are often called spongiform encephalopathies because of the post mortem appearance of the brain with large vacuoles in the cortex and cerebellum.

Protozoa

one celled organisms of the Kingdom Protista — most are unicellular although some are colonist.

Protozoology

science that deals with the study of protozoa

Psychrophile

bacteria that prefer cold, thriving at temperatures between 0 C and 25 C

Rickettsia

a genus of gram-negative, pathogenic, intracellular parasitic bacteria

Saprotroph

microbes that live upon dead and decaying organic matter

Secondary infection

infection caused by a different organism than the one causing the primary infection.

Septicemia

condition characterized by the multiplication of bacteria in blood

Spirillum (p1. Spirilla)

a genus of spiral bacteria having a corkscrew shape with a rigid cell wall and hair-like projections called flagella that assist in movement.

Spirochete

a genus of bacteria having a flexible cell wall but no flagella in the traditional sense. Movement in these organisms occurs by contractions (undulating) of long filaments (endoflagella) that run the length of the cell.

Sporadic

a disease which occurs occasionally or in scattered instances

Staphylococcus

a genus of gram-positive, nonmotile, opportunistic bacteria which tend to aggregate in irregular, grape-like clusters

Sterilization

a process of completely removing or destroying all life forms and/or their products on or in a substance

Streptobacilli

rod-shaped bacteria occurring in chains; a genus of bacteria containing gram negative rods which form a chain like colony

Streptococci

spherical shaped bacteria occurring in chains

Strict (obligate) aerobe

a microbe that can only live in the presence of free oxygen

Strict (obligate) anaerobe

a microbe that can only survive in the absence of free oxygen

Strict (obligate) parasite

an organism that is completely dependent on its living host for survival

Strict (obligate) saprophyte

an organism that can only survive on dead or decaying organic matter

Symbiotic

organisms live in close nutritional relationships; required by one or both members

Synergism

the harmonious action of two or more microorganisms producing an effect that neither could produce alone

Tetracocci

grouping of four spherical shaped cells

Thermophile

bacteria that thrive best at high temperatures, between 40 C and 70 C

Toxemia

the presence of toxins in the blood

Toxin

a poisonous substance of plant, animal, bacterial or fungal origin

Toxogenicity

the ability of an organism to produce poisons that can directly damage tissue

True Pathogen

an organism that due to its own virulence is able to produce disease

Vibrio

(L. to move rapidly, vibrate) a genus of spiral bacteria which are curved or bent rods that resemble commas