Microbio Exam 1 Definitions

Disinfection

The destruction or removal of vegetative pathogens not endospores. Usually used ONLY on inanimate objects.

Sterilization

The complete removal or destruction of all viable microorganisms including viruses and endospores. Used on inanimate objects

Antisepsis

Chemicals applied to body surfaces (skin) to destroy or inhibit vegetative pathogens.

Sanitization

Any cleansing technique that mechanically removes microbes

Dishwashing is an example of which method?

Sanitization

Degermation

Any process to reduce the number of microbes on the human skin

Surgical hand scrub is an example of which method?

Degermation

Antibacterial soap and using iodine preoperatively are examples of which method?

Antisepsis

5% bleach and boiling water are examples of which method?

Disinfection

Autoclaving is an example of which method?

Sterilization

Microbiostatic

Any process that temporarily prevents microbes from multiplying, does not eliminate them

Bacteriostatic and fungistatic are examples of which method?

Microbiostatic

Microbicide

Any chemical agent that kills pathogenic organism

Germicide is an example of which method?

Microbicide

Bactericide

Destroys bacteria (except for those in endospore stage)

Fungicide

Kills fungal spores, hyphae and yeasts

Virucide

Inactivate viruses, especially on living tissue

Sporicide

Can kill endospores, sterilizing agent

Microbial Death

Permanent loss of reproductive capability, even under optimal growth conditions

Human Death

Loss of vital signs, respirations, nervous function, heartbeat

Mechanism of Action

Antimicrobial agent’s effect on a cell

Desiccation

Gradual removal of water from cells leading to metabolic inhibition

Filtration

Mechanical removal of microbes by passing a gas or liquid through a filter

Chemotherapeutic drugs

Any chemical used in the treatment, relief, or prophylaxis of a disease

Prophylaxis

Use of a drug to prevent potential for infection of a person at risk

Antimicrobial Chemotherapy

The use of chemotherapeutic drugs to control infection

Antimicrobials

All-inclusive term for any antimicrobial drug, regardless of its origin

Antibiotics

Substances produced by the natural metabolic processes of some microorganisms that can inhibit or destroy other microorganisms

Semisynthetic Drugs

Drugs that are chemically modified in the laboratory after being isolated from natural sources

Synthetic Drugs

Antimicrobial compounds synthesized in the laboratory through chemical reactions

Narrow Spectrum (Limited)

Antimicrobials effective against a limited array of microbial types; ex: drug effective mainly on gram positive bacteria

Broad Spectrum (Extended)

Antimicrobials effective against a wide variety of microbial types; ex: drug effective against both gram positive and negative bacteria

Synergistic Effect

the effects of a combination of antibiotics are greater than the sum of the effects of the individual antibiotics

Microbial Drug Resistance

An adaptive response in which microorganisms begin to tolerate an amount of drug that would ordinarily be inhibitory

Selectively Toxic

Drugs should kill or inhibit microbial cells w/out simultaneously damaging host tissues

Superinfection

An infection occurring during antibiotic therapy that is caused by an overgrowth of drug resistant microorganisms

Therapeutic Index

The ratio of the dose of the drug that is toxic to humans as compared to its minimum effective dose

Normal/Resident Flora

Microbes that engage in mutual or commensal associations with humans

Infection

A condition in which pathogenic microbes penetrate host defenses, enter tissues, and multiply

Pathogen

Infectious agent

Infectious Disease

An infection that causes damage or disruption to tissues and organs

Transients

Microbes that occupy the body for only short periods

Residents

Microbes that become established

Microbial Antagonism

Bacterial flora benefit host by preventing overgrowth of harmful microbes

Endogenous Infections

Occur when normal flora is introduced to a site that was previously sterile

Exogenous Infection

Caused by organisms not normally present in the body

Probiotics

Introducing known microbes back into the body

Pathogenicity

Organisms’ potential to cause harm

True Pathogens

Capable of causing disease in healthy persons with normal immune defenses. Ex: influenza virus, plague bacillus, malarial protozoan

Opportunistic Pathogens

Cause disease when the host’s defenses are compromised or when they grow in part of the body that is not natural to them. Ex: pseudomonas sp & candida albicans

Virulence Factor

Any characteristic or structure of the microbe that contributes to the infection or disease; severity of disease

Portals of Entry

Characteristic route a microbe follows to enter the tissues of the body

S in STORCH

Syphilis

T in STORCH

Toxoplasmosis

O in STORCH

Other (Hep B, HIV, Chlamydia)

R in STORCH

Rubella

C in STORCH

Cytomegalovirus

H in STORCH

Herpes Simplex Virus

Infectious Dose

Minimum number of microbes required for infection to proceed

Adhesion

Microbes gain a stable foothold at the portal of entry; dependent on binding between specific molecules on host and pathogen

Antiphagocytic Factors

A virulence factor used by pathogens to avoid phagocytosis

Exoenzymes

Pathogens excrete extracellular enzymes that disrupt the structure of tissues; dissolve extracellular barriers and penetrate through or between cells

Toxigenicity

A pathogens capacity to produce toxins

Endotoxin

Toxin that is not secreted but is released after the cell is damaged

Exotoxin

Toxin molecule secreted by a living bacterial cell into the infected tissue

Incubation period

Time from initial contact with the infectious agent to the appearance of first symptoms; agent is multiplying but damage is insufficient to cause symptoms; several hours to several years

Prodromal Stage

Vague feelings of discomfort; nonspecific complaints

Period of Invasion

Multiplies at high levels, becomes well-established; more specific signs and symptoms

Convalescent Period

As person begins to respond to the infection; symptoms decline

Localized Infection

Microbes enter the body and remain confined to a specific site; boils, fungal skin infections, warts

Systemic Infection

Infection spreads to several sites and tissue fluids usually in the bloodstream; viral diseases, bacterial, fungal

Focal Infection

Occurs initially as a local infection, but circumstances cause microbe to be carried to other sites systemically (tuberculosis, streptococcal pharyngitis)

Mixed Infection

Several microbes grow simultaneously at the infection site; polymicrobial, human bites, dental caries, wound infection

Primary-Secondary Infection

An initial infection is complicated by a second one in the same or different location and caused by a different microbe; chicken pox

Acute Infection

Comes on rapidly, w/ severe but short-lived effects

Chronic Infection

Progress and persist over a long period of time

Sign

Objective evidence of the disease noted by an observer

Symptom

Subjective evidence of disease sensed by the patient

Syndrome

When a disease can be defined by a collection of signs and symptoms

Leukocytosis

Increase in total WBC

Leukopenia

Decrease in total WBC

Septicemia

Microorganisms are multiplying in the blood in large numbers and causing a systemic inflammatory response and/or sepsis

Bacteremia

Bacteria present in bloodstream

Viremia

Viruses present in the bloodstream

Asymptomatic (subclinical) Infections

Although infected, host does not show any signs of disease

Chronic Carrier

Person with a latent infection who sheds the infectious agent

Sequelae

Long-term or permanent damage to tissues or organs

Resevoir

A pathogen’s primary habitat in the natural world

Source

Individual or object from which an infection is actually acquired

Carrier

An individual who inconspicuously shelters a pathogen and spreads it to others; may or may not have experienced disease due to microbe

Asymptomatic Carrier

Shows no symptoms

Passive Carrier

Contaminated healthcare provider picks up pathogens and transfers them to other patients

Incubation Carriers

Spread the infectious agent during incubation period

Convalescent Carriers

Recuperating without symptoms, but still shed viable microbes

Chronic Carrier

Individual who shelters the infectious agent for a long period of recovery

Vector

A live animal that transmits an infectious agent from one host to another

Biological Vector

Actively participate in a pathogen’s life cycle, the site where it can multiply or complete its development

Mechanical Vector

Not necessary to the life cycle of an infectious agent and merely transports it without being infected

Zoonosis

An infection indigenous to animals but naturally transmissible to humans

Communicable Diseases

When an infected host can transmit the infectious agent to another host and establish an infection in that host