Bacterial Taxonomy and Nomenclature Quiz

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Questions and Answers

What is the correct order of taxonomy from broadest to most specific?

Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species (correct)

Kingdom, Phylum, Domain, Class, Order, Species, Genus, Family

Kingdom, Domain, Phylum, Class, Order, Family, Genus, Species

Domain, Kingdom, Phylum, Class, Family, Order, Genus, Species

Which of the following is true regarding bacterial cell walls?

All bacteria have a cell wall made of cellulose.

Bacterial cell walls are primarily composed of peptidoglycan. (correct)

Some bacteria lack a cell wall entirely. (correct)

Bacteria and Archaea have cell walls made of the same material.

What is a distinguishing factor for classifying bacteria based on motility?

Color of the bacteria when stained

Size of the bacterial colony

Shape of the bacteria under a microscope

Presence of flagella or axial filaments (correct)

Which statement about the naming of bacteria is false?

Trivial names should be italicized. Signup and view all the answers

When staining bacteria, which characteristic does not correspond to Gram-positive bacteria?

They are always diplococci. Signup and view all the answers

Which of the following correctly describes Archaea?

Unicellular and have cell walls composed of polymers. Signup and view all the answers

What are the criteria for classifying bacteria?

Morphology, Staining Reaction, Motility, Growth in Culture Media Signup and view all the answers

What is an example of a motility type exhibited by bacteria?

Tumbling Signup and view all the answers

What is the primary mechanism of action for fluoroquinolones?

Inhibiting DNA synthesis Signup and view all the answers

Which bacterium's multidrug resistance is particularly noted in the treatment of tuberculosis?

Mycobacterium tuberculosis Signup and view all the answers

What is the role of polymyxins in antibacterial treatment?

Disrupts outer membrane of Gram-negative bacteria Signup and view all the answers

Which antifungal agent works by binding with cell membrane sterols?

Amphotericin B Signup and view all the answers

What complicates the development of antiviral agents?

Viruses' reliance on host cellular machinery Signup and view all the answers

Which of the following describes sterilization?

Destruction of all microbes, including spores and viruses Signup and view all the answers

Antiprotozoal drugs primarily work by which mechanism?

Interfering with DNA and RNA synthesis Signup and view all the answers

What is one of the challenges in using antimicrobial drugs against fungal infections?

Fungi are eukaryotic cells similar to human cells Signup and view all the answers

Which of the following represents the complete hierarchy of the taxonomic classification for Staphylococcus aureus?

Domain: Bacteria, Phylum: Bacillota, Class: Bacilli, Order: Bacilliales, Family: Staphylococcaceae, Genus: Staphylococcus, Species: S. aureus Signup and view all the answers

What is the correct format for writing the scientific name of a species?

The genus name capitalized and the species epithet in lowercase, both in italics Signup and view all the answers

What does the abbreviation 'spp.' represent in bacterial nomenclature?

A designation of multiple species Signup and view all the answers

Which characteristic defines an organism's phenotype?

The observable physical traits of the organism Signup and view all the answers

Which of the following statements about bacterial nomenclature is true?

Scientific names can be abbreviated once they are first mentioned Signup and view all the answers

What does the abbreviation 'sp.' indicate in microbiology?

A single, unspecified species Signup and view all the answers

Which of the following is NOT a part of the taxonomic hierarchy as per the classification of Staphylococcus aureus?

Divisions Signup and view all the answers

What does the genus name indicate in the context of bacterial classification?

The broader group to which the bacteria belong Signup and view all the answers

What temperature do most pathogens grow best at?

37C Signup and view all the answers

What type of organisms thrive in acidic environments?

Acidophiles Signup and view all the answers

Which phase of the bacterial growth curve indicates a period of equilibrium?

Stationary Phase Signup and view all the answers

Which antimicrobial agents are specifically used to treat bacterial infections?

Antibacterial agents Signup and view all the answers

What is the primary factor preventing bacterial colonization in the gastrointestinal tract?

Presence of digestive enzymes Signup and view all the answers

What type of organisms are known to thrive in high salt concentrations?

Halophiles Signup and view all the answers

During which phase of the bacterial growth curve do cells double in number through binary fission?

Exponential Phase Signup and view all the answers

Which of the following best describes the requirement for an acceptable antimicrobial agent?

It must inhibit or kill pathogens without damaging the host. Signup and view all the answers

What defines a convalescent carrier?

A person recovering from an infectious disease who can transmit the pathogen. Signup and view all the answers

What type of transmission is characterized by infectious droplets larger than 5 μm?

Droplet transmission Signup and view all the answers

Which of the following best describes zoonotic diseases?

Diseases that humans acquire from animal sources. Signup and view all the answers

What is the main characteristic of an incubatory carrier?

They can transmit the pathogen before experiencing symptoms. Signup and view all the answers

During which phase of infectious disease does a patient experience actual symptoms?

Period of illness Signup and view all the answers

Which statement is true regarding vehicular transmission?

It involves transmission via contaminated inanimate objects. Signup and view all the answers

In which period does the patient first feel ‘out of sorts’ but does not yet display actual disease symptoms?

Prodromal period Signup and view all the answers

Vectors in disease transmission primarily refer to which of the following?

Biting insects and arachnids that carry pathogens. Signup and view all the answers

Study Notes

Taxa

Staphylococcus aureus is a bacteria, examples of its taxa include Domain: Bacteria, Phylum: Bacillota, Class: Bacilli, Order: Bacilliales, Family: Staphylococcaceae, Genus: Staphylococcus, Species: S.aureus
Nomenclature is the assignment of names to the various taxa according to international rules.
The name of a taxon between subclass and genus is formed by the addition of the appropriate suffix to the stem of the name of the type genus
A bacterium's species name consists of two parts: the genus name, which indicates the group it belongs to, and the species epithet, which, when combined with the genus name, makes the bacterium’s name unique.
The genus name and the species epithet form together the scientific name of the species, which is always written in italics.
The first letter of the genus should always be capitalized, whereas the first letter species epithet should be written in lowercase.
Trivial names are often used as a simplified way of naming a bacterial genus.
A trivial name should neither be written with capital first letter nor in italic.
The abbreviation “sp.” is used to designate a single species, whereas the abbreviation “spp.” is used to designate more than one species.
You can abbreviate the genus name after it has been written for the first time in a text, e.g. M.bovis.
Nicknames and slang terms frequently used within hospitals include: GC and gonococci (for Neisseria gonorrhoeae), Meningococci (for N.meningitidis), Pneumococci (for S.pneumoniae), Staph (for Staphylococcus or staphylococcal), Strep (for Streptococcus or streptococcal).

Microbial Characteristics

The complete collection of genes is referred to as the organism’s genotype or genome.
An organism’s complete collection of physical characteristics is known as the organism’s phenotype.
Taxonomy is the science of classifying living organisms
Nomenclature is the assignment of names to the various taxa according to international rules.

Bacterial Cell Structure and Morphology

Bacteria and Archaea are both unicellular and lack a nucleus.
Bacteria and Archaea are found everywhere there is moisture.
Bacteria and Archaea reproduce asexually.
Bacteria cell walls contain peptidoglycan (some lack a cell wall) but Archaea cell walls are composed of polymers.

Classifying Bacteria

Criteria for classifying bacteria include Morphology & Arrangement, Staining Reaction, Motility, and Growth in Culture Media.
When classifying bacteria, Morphology and Arrangement refers to the shape (cocci, bacilli, spirochetes), and how they are arranged (Clusters, chains, pairs).
When classifying bacteria, Staining Reaction refers to the reaction of the bacteria to a Gram stain, Gram positive bacteria will stain blue to purple and Gram negative bacteria will stain pink to red.
When classifying bacteria, Motility refers to whether or not the bacteria are motile, and associated with the presence of flagella or axial filaments.
When classifying bacteria, Growth in Culture Media refers to the nutritional requirements such as Hemolysin, vitamins, minerals, X- and V-Factor, salts, etc, and Colony Morphology such as Shape, Margin, Elevation, Size, Texture, Appearance, Pigmentation and Optical property.

Bacterial Growth Curve

The Bacterial Growth Curve consists of four phases: Lag, Exponential or Log, Stationary, and Death.
In the Lag Phase, newly inoculated bacteria are adopting to the new environment.
In the Exponential or Log Phase, cells are dividing by binary fission and doubling in numbers in each generation time.
In the Stationary Phase, there is a period of equilibrium wherein microbial death balances the number of new cells.
In the Death Phase, shortage of available nutrients causes death rate to exceed reproductive rate.

Antimicrobial Agents

An antimicrobial agent is any chemical (drug) used to treat an infectious disease, either by inhibiting or by killing pathogens in vivo.
Drugs used to treat bacterial diseases are called antibacterial agents, whereas those used to treat fungal diseases are called antifungal agents.
Drugs used to treat protozoal diseases are called antiprotozoal agents, and those used to treat viral diseases are called antiviral agents.
To be acceptable, an antimicrobial agent must inhibit or destroy/kill the pathogen without damaging the host.
Fluoroquinolones are bactericidal drugs that inhibit DNA synthesis.
Polymyxin- most effective against Gram Negative Bacteria due to its ability to disrupt the outer membrane.
In some cases, a single antimicrobial agent is not sufficient to destroy all the pathogens that develop during the course of a disease; thus, two or more drugs may be used simultaneously to kill all the pathogens.
In tuberculosis, for example, in which multidrug-resistant strains of Mycobacterium tuberculosis are frequently encountered, four drugs (isoniazid, rifampin, pyrazinamide, and ethambutol) are routinely prescribed, and as many as 12 drugs may be required for especially resistant strains.

Antifungal Agents

Antifungal Agents often work by binding with cell membrane sterols (e.g., nystatin and amphotericin B), interfering with sterol synthesis (e.g., clotrimazole and miconazole), or blocking mitosis or nucleic acid synthesis (e.g., griseofulvin and 5-flucytosine).
It is much more difficult to use antimicrobial drugs against fungal and protozoal pathogens, because they are eukaryotic cells.
Thus, antifungal and antiprotozoal tend to be more toxic to the patient.

Antiprotozoal Agents

Antiprotozoal drugs are usually quite toxic to the host and may work by interfering with DNA and RNA synthesis, or by interfering with protozoal metabolism.

Antiviral Agents

Antiviral agents are particularly difficult to develop and use because viruses are produced within host cells.
Viruses are referred to as acellular microbes because they are not considered living organisms.
The first antiviral agent effective against human immunodeficiency virus (HIV) (the causative agent of acquired immune deficiency syndrome or acquired immunodeficiency syndrome [AIDS])—zidovudine (also known as azidothymidine [AZT])—was introduced in 1987.

Microbial Growth Inhibition in Vitro

Sterilization involves the destruction or elimination of all microbes, including cells, spores, and viruses.
When something is sterile, it is devoid of microbial life.
Disinfection- describes the elimination of most or all pathogens (except bacterial spores) from nonliving objects.

Epidemiologic Terminologies

A carrier is a person colonized with a particular pathogen, but the pathogen is not currently causing disease in that person.
A passive carrier carries the pathogen without ever having had the disease.
An incubatory carrier is a person who is capable of transmitting a pathogen during the incubation period of a particular infectious disease.
A convalescent carrier harbors and can transmit a particular pathogen while recovering from an infectious disease.
An active carrier carries the pathogen without ever having had the disease.

Zoonotic Diseases

Zoonotic Diseases: are infectious diseases that humans acquire from animal sources.
A variant form of Creutzfeldt Jakob (CJ) disease in humans, called variant CJ disease, may be acquired by ingestion of prion infected beef from cows with bovine spongiform encephalopathy (BSE or “mad cow disease”).

Modes of Transmission:

Droplet transmission is the transfer of pathogens via infectious droplets (particles 5 μm in diameter or larger) released by coughing, sneezing, and even talking.
Airborne transmission is the dispersal of droplet nuclei, which are the residue of evaporated droplets, and are smaller than 5 μm in diameter.
Vehicular Transmission involves contaminated inanimate objects (“vehicles”), such as food, water, dust, and fomites.
Vectors include various types of biting insects and arachnids.
Contact Transmission involves transmission of infectious organisms by direct contact (i.e., skin-to-skin) or indirect contact (i.e., inanimate objects).

Pathogenesis of Infectious Diseases

Four Phases in the Course of an Infectious Disease: Incubation Period, Prodromal period, Period of illness, and Convalescence
During the Incubation Period, there is a time between exposure to pathogen and onset of symptoms.
During the Prodromal period, the patient feels “out of sorts” but not experience actual symptoms of the disease.
During the Period of illness, the patient experiences typical symptoms associated with that particular disease.
During the Convalescence phase, the patient is recovering and regaining strength.

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Description

Test your knowledge on the taxonomy and nomenclature of bacteria, focusing on Staphylococcus aureus. This quiz covers the classification system, name formation, and the rules for writing scientific names. Perfect for students studying microbiology or related fields.