Microbiology Taxonomy, Microbiota, and Infectious Diseases Concepts

A comprehensive set of Q&A flashcards covering taxonomy, naming conventions, microbiota concepts, host-microbe interactions, and infectious disease classifications.

What is the primary purpose of sterilizing instruments and decontaminating surfaces in healthcare settings?

To decrease transmission of infectious agents between healthcare providers and patients, and between patients, thereby reducing infection and disease incidence.

How are microorganisms classified in biology?

Into eight hierarchical rankings from domain to species based on shared features.

What mnemonic is commonly used to remember the eight taxonomic ranks from domain to species?

Dear King Philip Came Over For Good Spaghetti.

For microorganisms, which parts of the taxonomic pyramid are used in binomial nomenclature?

Genus and species.

How should genus and species names be formatted in scientific writing?

Genus is capitalized and italicized (or underlined); species is lowercase and italicized (or underlined).

What is binomial nomenclature?

The two-name scientific naming system using genus and species to identify organisms.

What is the first name in binomial nomenclature and how is it written?

The genus; it is capitalized and italicized (or underlined).

What is the second name in binomial nomenclature and how is it written?

The species; it is lowercase and italicized (or underlined).

What is the abbreviated form of a genus after the first full mention (e.g., Escherichia coli as E. coli)?

Genus abbreviation used in subsequent references within the same document.

What are the major cellular categories used to distinguish microorganisms?

Prokaryotes (no membrane-bound nucleus) and Eukaryotes (have a nucleus).

What are the possible eukaryotic groups?

Animals, plants, fungi, and protists.

What are the two prokaryotic domains?

Bacteria and Archaea.

Give an example of a genus and species and its common abbreviation.

Escherichia coli; abbreviated as E. coli.

Which organism genus/species is responsible for flesh-eating disease and strep throat?

Streptococcus pyogenes (gram-positive cocci).

What disease does Vibrio cholerae cause and what is its shape?

Cholera; curved rod (vibrio).

How does Staphylococcus epidermidis appear under the microscope?

Grapelike clusters of cocci.

What disease is Neisseria gonorrhoeae associated with?

Gonorrhea.

Why can gram-negative rods look similar despite being genetically different?

Morphology can be misleading; organisms can share similar shapes but have substantial genetic differences.

What is the basic unit of taxonomy and how is species defined differently for eukaryotes vs. prokaryotes?

Species is the basic unit. For eukaryotes, groups that reproduce sexually and produce fertile offspring; for prokaryotes, defined by phenotype, physiology, and genomic markers due to clonal reproduction.

What is a strain in microbiology?

A genetic variant or subtype of a species, often designated with numbers or letters after the species name (e.g., E. coli K-12; O157:H7).

What is a mutualistic host–microbe relationship?

Both the microbe and the host benefit.

What is commensalism in host–microbe interactions?

The microbe benefits while the host is neutral (no apparent benefit or harm).

What is parasitism in host–microbe interactions?

The microbe benefits while the host is harmed.

What is the microbiome?

The microbiota plus all their associated genetic material and gene products within the environment.

What proportion of human cells are microbial according to the notes?

Approximately 90% microbial cells to 10% human cells.

What term describes humans plus their microbiota functioning as a unit?

A metaorganism.

When does initial microbial colonization begin?

During delivery at birth, influenced by delivery method and feeding.

What is dysbiosis?

Disruption of the normal microbiota, associated with disease risk.

What is eubiosis?

A healthy microbiota state.

How can antibiotic therapy affect the microbiota?

Broadly disrupts microbiota, potentially causing diarrhea, yeast infections, thrush, and opportunistic infections.

What is the gut–brain axis?

A bidirectional communication pathway where the microbiota influences brain function and mood.

What is a pathogen?

A microbe with the potential to cause disease.

What is an infection?

The invasion and multiplication of pathogens within a host.

What is an infectious disease?

Illness or damage to the host caused by infection; infection does not always lead to disease.

What is a true pathogen?

A pathogen that can cause disease in healthy individuals without a weakened host.

What is an opportunistic pathogen?

A pathogen that causes disease only when the host is compromised or conditions favor infection.

What is an emerging pathogen?

A pathogen newly appeared or identified in a population.

What is a reemerging pathogen?

A known pathogen that has reappeared due to changes in hosts, environment, or the pathogen itself.

What is a zoonotic disease?

An infectious disease that spreads from animals to humans through an animal reservoir.

What is an epidemic vs a pandemic?

Epidemic: sudden widespread increase in cases in a region; Pandemic: global spread across continents.

What is an incidental (dead-end) host?

An accidental host in which the pathogen cannot be transmitted onward.

What role do environmental changes play in reemerging pathogens?

Deforestation, urbanization, antimicrobial misuse, and climate change can drive reemergence and broaden host range.

What is the difference between respiratory pathogens and non-transmitted environmental pathogens?

Respiratory pathogens are highly transmissible via the air; non-transmitted environmental pathogens do not typically spread between humans.

A cellular

No living

Prokaryotes

Lack membrane , enclose nucleus

Eukaryotic

Membrane bond , nucleus and organelles