Microbiology and Infectious Disease Overview

These flashcards cover key concepts in microbiology and infectious disease, including definitions of terms and important theories.

Microbiology

The study of organisms that are too small to be seen without magnification.

Prokaryotic Organisms

Simple cells that lack a nucleus and have existed on Earth for about 3.5 billion years.

Eukaryotic Organisms

Complex cells that contain a true nucleus.

Symbiotic Relationships

Types of relationships between microbes and their hosts where both benefit, one benefits with no harm to the other, or one benefits at the expense of the other.

Mutualism

A type of symbiotic relationship where both organisms benefit.

Commensalism

A symbiotic relationship where one organism benefits while the other is not harmed.

Parasitism

A relationship where one organism benefits at the expense of the host.

Normal Microbiota

Microbes that live in and on the human body, often providing benefits such as vitamin production and protection from harmful bacteria.

Pathogens

Microorganisms that cause harm and diseases.

Emerging Diseases

Newly identified conditions that are being reported as threats to health.

Reemerging Diseases

Older diseases that are increasing in the population again.

Spontaneous Generation

The early belief that life could arise from nonliving matter.

Germ Theory of Disease

The theory that microorganisms are the cause of many diseases, established through the work of scientists like Louis Pasteur and Robert Koch.

Koch's Postulates

A series of steps to establish the causal relationship between a microbe and a disease.

Taxonomy

The science of classifying and naming living organisms.

Binomial Nomenclature

A system of naming organisms using two names: genus and species.

Infectious Dose (ID)

The minimum number of pathogens required to cause an infection.

Virulence

The degree of pathogenicity of a microorganism, reflecting how severe an illness it can cause.

Toxins

Chemical products that have poisonous effects on other organisms, classified as endotoxins and exotoxins.

Adhesion

The process by which pathogens attach to host tissues to initiate infection.

Biofilms

Communities of microorganisms that adhere to surfaces and share nutrients.

Cross feeding

Is a nonsymbiotic relationship, microbes sharing a habitat, feed off substances release by other organisms, NOT REQUIRED but is BENEFICIAL

Amensalism

Nonsymbiotic relationships, one member of an association produces a substance that harms or kills another

Janssen

First compound microscope

Galileo

Improved Jensen’s scope

Robert Hooke

Further improved scope and coined the term cell

Leeuwenhoek

“Animalcules” in rainwater

Sterile

Free of all infectious agents including endospores, viruses and prions

Sterilization

Process to create sterile

Aseptic technique

Aimed at reducing pathogens but don’t necessarily sterilize

Pasteurization

Process to kill most spoilage bacteria in beverages

Edward Jenner

Developed vaccine, before Jenner-variolation, use cowpox, paved the way for development of immunology

Hans Christian Gram

Developed Gran stain to distinguish between different types of bacteria that look the same

Types of Domain’s

Domain Bacteria , Domain Archaea , Domain Eukarya

Infection

=pathogen

Transients

Stay around for just a short time (hygiene)

Residents

More permanently, stable and predictable, help with host defenses

Site that harbor normal resident microbes

Skin, upper respiratory tract. Gastrointestinal tract, outer opening of urethra, external genitalia, vagina, external ear and canal, external eye

Pathogenicity

Organisms ability to cause infection/disease

True/primary pathogens

Causing disease in healthy people with normal immune systems

Opportunistic pathogens

Cause disease when hosts defenses are compromised or when they are established in a part of the body not natural to them

1. Entry

Portal of entry is route a microbe enter the body to initiate infection

Exogenous

From outside the body

Endogenous

From microbiota or latent infection

Skin

Very common entry point , nicks abrasions or punctures, agents create their own passageways using digestive enzymes, enter via insect bites/ via contaminated needles

GI tract

Food , drink , other ingested substances, pathogens are adapted to survive digestive enzymes and pH changes

Respiratory tract

Oral and nasal cavities, greatest number of pathogens

Urogenital Tract

Entry for pathogens, intercourse or intimate direct contact, STI/STD

Surviving Host Defenses

Organisms can’t invade and get settled without staying under the radar , virulence factos help with this , antiphagocytic factors , exoenzymes , toxins

Mucinase

Digests the protective coating on mucus membranes (amoebic dysentery)

Collagenase

Digests the protein fibers of connective tissue helps with invasion (clostridium/parasitic worms)

Hyaluronidase

Digest polysaccharides that hold cells together (staphyococci, clostridia, streptococci, pneumococci)

Keratinase

Digests principal component of skin and hair (ringworm fungal infections)

Endotoxins

Not secreted; released after cell is damaged or lysed (toxic in higher quantities systemic and less specific)

Exotoxins

Secreted by a living bacterial cell (toxic in small amounts specific to a cell type)

Causes Damage to the Host

Disruption of host cell function, use of host cell nutrients, production of wastes, direct destruction of host cell through multiplication, adverse effects of enzymes and toxins (this is where disease occurs)

Exiting host

Portals of exit are ways microbes leave same or not ( respiratory tract , gastrointestinal tract , genitourinary tract , skin , blood)