Exam 1 Review Flashcards
Cellular, living microorganisms such as bacteria, archaea, fungi, protists, and helminths.
Microorganisms
A pathogen that does not require a weakened host to cause disease.
True Pathogen
Pathogens that only cause disease when their host, is weakened in some way.
Opportunistic Pathogens
Four principles that establish the criteria for determining the causative agent of an infectious disease:
- ) The same organism must be present in every case of the disease.
- ) The organism must be isolated from the diseased host and frown as pure culture.
- ) The isolated organism should cause the disease in question when it is introduced into a susceptible host.
- ) The organism must then be re-isolated from the inoculated, diseased animal.
Koch’s Postulate of Disease
Also known as nosocomial infections; an infection that a patient develops while receiving care in a healthcare setting.
Health acquired infection, HAI
Germ free practices; term applied to techniques designed to prevent the introduction of contaminating microbes to a patient, a clinical sample, or others in the healthcare setting; methods that present healthcare- acquired infections by preventing the introduction of potentially dangerous microbes.
Aseptic Technique
States that microbes cause infectious diseases.
Germ theory of disease
Normal human flora, including bacteria, archaea, and eukaryotic microbes.
Normal Microbiota
A type of symbiotic relationship that has no perceived benefit or cost to them.
Commensalism
A type of symbiotic relationship that hurts the host.
Parasitism
A type of symbiotic relationship that helps the host.
Mutualistic
A term describing the general ability of an infectious agent to cause disease.
Pathogenic
Sticky microbial communities made up of single or diverse species; they allow microbes to coordinate responses with an environment.
Biofilms
Differential staining procedure that distinguishes between cells with and without waxy mycolic acid cell walls; mycobacterium tuberculosis and mycobacterium leprae are examples of clinically important acid-fast bacteria.
Acid Fast Stain
A staining procedure that allowed us to classify bacteria as either Gram-positive or Gram-negative; Following the gram staining procedure gram positive cells appear purple while gram negative appear pink. The final outcome of the gram stain is based on the cell wall properties of the stained cells.
Gram stain
Is a differential stain used to visualize bacterial endospores. Endospores are formed by a few genera of bacteria, such as Bacillus. By forming spores, bacteria can survive in hostile conditions. Spores are resistant to heat, desiccation, chemicals, and radiation.
Spore stain
Staining techniques that use just one dye; typically only size, shape, and cellular arrangement can be determined using simple stains.
Simple Stain
Includes the prokaryotes people encounter on an everyday basis. Most bacterial species are heterotrophic; that is, they acquire their food from organic matter. The largest number of bacteria are saprobic, meaning that they feed on dead or decaying organic matter.
Domain Bacteria
Organisms that are all unicellular and lack a membrane bound nucleus. They also lack other membrane bound organelles, and have a much simpler genetic makeup that eukaryotic cells. Bacteria and archaea are prokaryotes.
Prokaryotic Cells
The three basic bacterial shapes are coccus (spherical), bacillus (rod-shaped), and spiral (twisted), however pleomorphic bacteria can assume several shapes. Cocci (or coccus for a single cell) are round cells, sometimes slightly flattened when they are adjacent to one another.
Shape or arrangement of a prokaryote
Cells appear pink, thin layer of peptoglygican
Gram negative
Cells appear purple thick layer of peptoglycigan
Gram Positive
Bacteria (also known as acid-fast bacilli or AFB) are microorganisms resistant to decolorization by an acid, hence, the term acid-fast. Acid fastness is a unique characteristic of M. tuberculosis. However, other mycobacterial species may exhibit the same feature.
Acid Fast Mycolic acid
A term that describes cells with a single flagellum.
Monotrichous Flagella
A term applied to cells with a tuft or cluster of flagella at one pole of the cell.
Lophotrichous Flagella
Flagella located in the space between the plasma membrane and the cell wall. These unique flagella allow spirochetes to move with their distinct corkscrew motion.
Periplasmic Flagella
A term that describes cells with one or more flagella present at each end of the cell.
Amphitrichous Flagella
Organisms that can thrive between about-20C and 10C and that tend to live in environments that are consistently cold like the artic.
Psychrophiles
Cold tolerant organisms that grow at about 0-30C and are associated with foodborne illness because they grow at room temperature as well as in refrigerated and frozen foods.
Psychotrophs
Organisms that prefer moderate temperatures and tend to grow best around 10-50C, a grange that includes body temperatures. Most pathogens are part of the mesophilic temperature group and cover a broad range of the plane, from soil to streams to dwelling in eukaryotic organisms.
Mesophiles
Organisms that prefer warm temperatures of roughly 40-75C; they dwell in compost piles and hot springs.
Thermophiles
Organisms that thrive in high salt environments.
Halophiles
Self feeding organisms, such as plants and other photosynthetic organisms, that use carbon fixation to convert inorganic carbon into organic carbon.
Autotroph
Organisms that can harvest energy from light to make ATP.
Phototroph
Organisms that break down chemical compounds for energy; organisms that rely on energy found in the chemical bonds of their nutrients to make ATP.
Chemotroph
Organisms, such as humans, that cannot fix carbon; they require an external source of organic carbon in order to live and grow.
Heterotroph
Technique that helps to isolate a specific species of microbe for study, accomplished by spreading the sample thinly enough on an agar plate, so that the various cells in the sample are sufficiently separated and can give rise to individual colonies.
Streak Plate Technique
A sticky carbohydrate-based structure made by some prokaryote. A well-organized glycocalyx that is tightly associated with the cell wall. Presence of a capsule often increases pathogenicity the ability to cause disease, since it promotes adhesion to host tissues, and provides some protection against host immune cells by interfering with phagocytes.
Capsule protection