bios242 week 4

Disinfection

Destruction or removal of vegetative pathogens (not endospores) on inanimate objects.

Sterilization

Complete removal or destruction of all viable microorganisms on inanimate objects.

Antisepsis / Degermation

Application of chemicals to body surfaces to destroy or inhibit vegetative pathogens.

Decontamination / Sanitization

The mechanical removal of most microbes.

Pasteurization (Flash method)

Heat treatment at 71.6 °C for 15 seconds to kill pathogens while retaining flavor.

Pasteurization (Batch method)

Heat treatment at 63 °C to 66 °C for 30 minutes.

Ionizing radiation

X-rays, cathode, and gamma rays that remove electrons and sterilize food.

Nonionizing radiation (UV)

Raises atoms to higher energy, creating pyrimidine dimers that disrupt DNA replication.

Halogens

Group 7 elements (fluorine, bromine, chlorine, iodine) that act as microbicides.

Antimicrobials

All-inclusive term for any drug targeting any type of microorganism.

Antibiotics

Chemicals produced naturally or synthetically that target and inhibit or destroy bacteria.

Broad spectrum antibiotics

Antimicrobials effective against a wide variety of microbes, like tetracycline.

Narrow spectrum antibiotics

Antimicrobials effective against a limited array of microbial types, like isoniazid.

5 Targets of Antibacterial Drugs

Cell wall, cytoplasmic membrane, nucleic acids, folic acid synthesis, and protein synthesis.

Genetic sources of drug resistance

Chromosomal gene mutations or acquiring new genes via horizontal gene transfer.

6 Mechanisms of drug resistance

Inactivation, decreased uptake, drug removal, binding site mutation, alternative pathways, dormancy.

How antibiotic resistance spreads

Resistant bacteria survive drug exposure, flourish, and share resistance genes.

Human drivers of drug resistance

Overuse in healthcare/agriculture and inadequate infection control.

Mutualism

An obligatory and mutually beneficial relationship between organisms.

Commensalism

One organism benefits while the other is unaffected and unharmed.

Parasitism

One organism benefits at the expense and harm of the host.

Microbial antagonism

Competition where microbes inhibit or destroy other organisms to survive.

Opportunistic pathogen

A nonpathogenic microbe that causes disease in immunocompromised hosts.

Biosafety Level 1 (BSL-1)

Handling microbes with low infection hazard; generally nonpathogenic to healthy people.

Biosafety Level 2 (BSL-2)

Handling moderate-risk pathogens that can cause disease in healthy humans.

Biosafety Level 3 (BSL-3)

Handling pathogens causing severe or lethal disease, especially via inhalation.

Biosafety Level 4 (BSL-4)

Handling highly virulent, lethal pathogens with high risk of aerosol transmission.

Portals of entry

Pathways like skin, GI tract, respiratory tract, urogenital tract, or pregnancy.

Host attachment structures

Fimbriae, capsules, slime layers, surface proteins (bacteria/fungi); spikes (viruses).

3 Host defense evasion strategies

Leukocidins, capsules resisting phagocytosis, and epigenetic changes to host DNA.

Localized infection

An infection where the microbe remains confined to a specific tissue.

Systemic infection

An infection that spreads to several sites and fluids, usually via bloodstream.

Focal infection

When an infectious agent breaks loose from a local site to other tissues.

Mixed infection

Several different microbe types establishing themselves simultaneously at an infection site.

Primary vs. Secondary infection

Primary is the initial infection; secondary is a complication by a different microbe.

Acute vs. Chronic infection

Acute has rapid onset and short duration; chronic persists over a long period.

Sign

Objective, observable evidence of disease (e.g., fever, septicemia).

Symptom

Subjective evidence of disease sensed only by the patient (e.g., chills, fatigue).

Syndrome

A disease defined by a specific group of signs and symptoms.

5 Stages of clinical infection

Incubation, prodromal, height of infection (acute), convalescence, and continuation.

Reservoir

The primary natural habitat where a pathogen originates (living or nonliving).

5 Types of human carriers

Asymptomatic, incubating, convalescent, chronic, and passive.

Arthropod vector

Insects like fleas, ticks, and mosquitoes that transmit pathogens to hosts.

Nonliving reservoirs

Soil, water, and air that harbor infectious pathogens.

Horizontal transmission

Spread of disease through a population from one infected individual to another.

Epidemiology

The study of the frequency and distribution of disease in populations.

Incidence

The number of new disease cases in a population over a specific time.

Prevalence

The total number of existing disease cases in a population.

Epidemic

A sudden increase in disease cases beyond what is normally expected.

Endemic

A disease that exhibits a relatively steady frequency over a long period.

Sporadic

Occasional cases of disease occurring at irregular intervals in random locations.

Pandemic

The spread of an epidemic across multiple continents.