Micro Exam 3

Chemotherapy

Use of drugs to treat a disease

Antimicrobial Drugs

Interfere with the growth of microbes within a host

Antibiotic

A substance produced by a microbe that, in small amounts, inhibits another microbe

Selective toxicity

A drug that kills harmful microbes without damaging host cells

Who discovered penicillin and when?

1928, Alexander Fleming

Who performed the first clinical trials of penicillin and when?

Howard Florey and Ernst Chain, 1940

Almost all antibiotic-producing microbes do what?

Sporulate

Broad Spectrum

Wide range of bacteria against which drug is useful

Narrow Spectrum

Small range of microbes against which drug is useful

Superinfection regarding microbiota

Killing normal microbiota (aka normal flora) along with pathogens, leaving room for opportunistic pathogens to fluorish

Superinfection

Infection that occurs while you are being treated for another infection

Superinfection regarding super bug

Killing drug-sensitive pathogen cells, but not killing drug-resistant cells

Inhibition is _____ against Gram-positive cells, ____ against Gram-negative cells, and ____ to animal cells

Effective, less effective, harmless

Inhibition of protein synthesis is equally ______ against Gram-positive and Gram-negative cells. Why?

Effective, similar ribosomes

Inhibition of cytoplasmic membrane can ____ _______ of cell membrane

Change permeability

Inhibition of DNA synthesis can do what?

Can interfere with humans

T/F: Inhibition of synthesis of essential metabolites' effect could be indirect

True

Beta-lactams prevents what?

Cross-Linkages of peptidoglycan

What is a cell wall synthesis inhibitor?

Beta-lactams

What can break down B-lactams?

B-lactamases

T/F: B-lactams are difficult to become resistant to

False

Derivatives of B-lactams include:

- Carbapenems
- Monobactams
- Cephalosporins

Glycopeptide antibiotics include:

Vancomycin

Aminoglycosides

A class of a protein synthesis inhibitors

Tetracyclines

A class of a protein synthesis inhibitors

Macrolides

A class of a protein synthesis inhibitors

Lipopeptides

A class that inhibits cytoplasmic membrane

Rifamycin

A class of Nucleic acid synthesis inhibitor. Inhibits RNA polymerase and penetrates body tissues very well. Strange side effects.

What is the difference between Quinolones and Fluoroquinolones.

A fluorine group

Quinolones and Fluoroquinolones

A class of Nucleic acid synthesis inhibitors

Sulfonamides

Inhibitor of metabolism

T/F: Fungal cells are similar to that of a human

True

We have ______ in our membranes, Fungus have ______ in theirs

Cholesterol, Ergosterol

What do Antifungal drugs do to fungi synthesis?

Blocks ergosterol synthesis

Flucytosine

An analog of cytosine

How do we treat for viruses

Targets the enzyme that it carries

What is the Kirby-Bauer method?

Disk-Diffusion test

What is an E-Test?

A strip with antibiotic gradient

What does an E-Test help you find?

Minimum inhibitory concentration

What does a bacterium do to an enzyme become resistant to an antibiotic ?

Either destroy or modify the enzyme in a drug

How does a bacterium become resistant regarding the target cell?

Bacterium alter a drugs target site

T/F: Bacterium can never prevent a drug from penetrating a cell

False

Define Taxonomy

The science of categorizing organisms

Why is taxonomy important?

Provides universal names for all biological organisms to prevent any confusion anywhere in the world

Define Systematics (phylogeny)

Study of evolutionary history of organisms

What do systematics demonstrate?

Relatedness among organisms and the evolutionary history of organisms

What domain came first from LUCA?

Bacteria

What is the difference between Eukaryotes and Prokaryotes?

Prokaryotes are always unicellular, while eukaryotes are often multi-celled organisms. Additionally, eukaryotic cells are more than 100 to 10,000 times larger than prokaryotic cells and are much more complex. The DNA in eukaryotes is stored within the nucleus, while DNA is stored in the cytoplasm of prokaryotes.

T/F: It is incredibly easy to find fossilized prokaryotes

False

How do we use binomial nomenclature?

Genus+ specific epithet

What language do we use in binomial nomenclature?

Latin; dead language

List the Taxonomic hierarchy in order from largest to smallest

Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species, Subspecies, Strain, Serova, Pathovar, Sequivar

What is not applicable in taxonomic hierarchy for prokaryotes

Kingdom

Define Animalia

Multicellular: no cell

Viral Species

Population of viruses with similar characteristics that occupies a particular ecological

Prokaryotic species

A population of cell with similar characteristics

Eukaryotic species

A group of closely related organisms that breed among themselves

Strain

Genetically different cells within a clone

T/F: Only cultivated strains can be named

True

T/F: Only pure cultures can be named

True

What is another name for pure?

Axenic

High-throughput biochemical testing

1.) One tube containing media for 15 biochemical tests is inoculated

Antigen-antibody tests

Usually used for very specific pathogens. Extremely accurate and sensitive

ELISA

Enzyme-linked immunosorbent assay

16S Gene

-

Pelagibacter ubique is the most common bacterium

What does Bartonella cause?

Cat Scratch Disease

Rickettsia species are ________ born.

Arthropod

Brucella, Erlichia, and Rickettsia are _______ parasites

Intercellular

Wolbachia species live were?

Inside of insects and other animals

What causes whooping cough?

Bordetella pertusis

Neisseria species are common pathogens that cause:

-N. gonorrhoeae causes gonorrhea
-N. meningitis causes meningitis

Pseudomonas is a _____ ______ genus

VERY large

Legionella pneumophila is difficult to grow and must be grown on:

Activated charcoal based medium

How can a person get Q-fever?

Bad milk

Where can Vibrio be found?

Coastal water and stagnant water

Proteobacteria Gammaproteobacteria Enterobacteriales cause what?

Pathogens

Escherichia Coli

a genus of enteric bacteria

Salmonella

Close cousin of E. coli. Common avian intestinal organism.

Shigella

Basically E. coli. Causes shigellosis (E. coli on steroids)

Enterobacter

Klebsiella

Serratia

Can contaminate indwelling medical devices. Tested by the military

Proteus

Swarming colonies (highly motile). Causes Urinary tract infections

Yersinia and Plague

Causes the Black Death.

Erwinia

Rod-shaped motile bacteria that attack plants

Proteobacteria are gram _____

Negative

Pasteurella

In the saliva of Komodo dragons

Myxococcus

Have external spores (used for reproduction)

Campylobacter

Causes foodborne illnesses.

Helicobacter causes what?

H. pylori causes most ulcers. Lives in stomach acid

Cyanobacteria

Go through oxygenic photosynthesis

Chlorobi

Green sulfur bacteria

What is the most common bacterium in the human gut.

Bacteroides

Fusobacteria Fusobacterium

Fusiform (spindle shaped), anaerobic. Found in the mouth and gut of mammals

Why is it difficult to find new antibiotics/antimicrobials?

We have new drugs, but bugs become resistant, so it's a constant race against those bacteria, and we have to find newer and newer products. But the main hurdle for antibiotic research and development remains financial

What is drug spectrum?

The antimicrobial spectrum of an antibiotic means the range of microorganisms it can kill or inhibit

Why does drug spectrum matter?

Narrow-spectrum antibiotic allow to kill or inhibit only those bacteria species that are unwanted. Broad-spectrum antibiotics, low dosage and prolonged antibiotic therapy favor the development of resistance.

What methods could a bacterium use to become resistant to an antibiotic?

Through mutation and selection. For example, some bacteria have developed biochemical “pumps” that can remove an antibiotic before it reaches its target, while others have evolved to produce enzymes to inactivate the antibiotic

How do we test effectiveness of antibiotics?

Bacterial isolates are generally tested for susceptibility to antibiotics using an in vitro test. Susceptibility testing.