Chapter 12 Microbial Control Chemotherapy

Antibiotics

Common metabolic products produced by aerobic bacteria and fungi that inhibit other microbes in the same habitats causing less competition of nutrients and space

semisynthetic antibiotics

Drugs that are chemically modified in the lab after being isolated from natural sources

synthetic antibiotics

antimicrobial compounds synthesized entirely in the lab through chemical reactions

Which antibiotics damages the cell wall and causes lysis in bacteria > they are also in the Narrow spectrum (gram post) + most selectively toxic (no harm to human but to pathogen)

Penicillin

Bacitracin

Vancomycin

Which antibiotic inhibits ribosomal protein synthesis  in bacteria and is broad spectrum

EAT THAT CHLORINE SAUCE

Erythromycin

Tetracycline

Chloramphenicol

Streptomycin

Which Inhibit folic acid metabolism  in bacteria

Sulfa drugs (inhibit in some protozoa too)

Trimethoprim

What inhibits mycolic acid synthesis for the cell wall in bacteria Narrow Spectrum (gram positive)

Isoniazid

What antibiotic causes buildup of toxic free radicals in protozoa 

Metronidazole

What inhibits mycolic acid synthesis for the cell wall in bacteria Narrow Spectrum (gram positive) EXTRA QUESTION

Isoniazid

What  paralyzes muscular system in helminths 

Piperazine

What stops viral replications in viruses

Cyclovirs

What blocks formation of DNA from RNA strand in viruses  

Azidothymidine

competitive inhibition what and causes what

metabolic analogs (resemble natural cellular metabolites)

• drugs that competes with normal substrate for enzyme’s active sites

• causes cellular metabolism to slow or stop

What are 3 competitive inhibition > short term retention

Sulfonamides aka sulfa drugs

trimethoprim

Retrovir

synergistic compounds

Combination of antibiotics that enhances bacterial killing leading to a strong effect then a individual antibiotic

What is an example of an synergistic compound said in lecture

Clavulanic acid + Amoxicillin is a combination antibiotic known as Augmentin

• Amoxicillin is a β-lactam antibiotic that inhibits bacterial cell wall synthesis.

• Clavulanic acid inhibits β-lactamase enzymes = prevents break down of amoxicillin

beta-lactam antibiotics + major target

Penicillin and cephalosporins

interferes with cell wall synthesis

semi-synthetic penicillin’s > the types

PC MANT

Natural penicillin from microbial fermentation then modified

penicillin V

Ticarcillin

Cloxacillin

Nafcillin

Ampicillin

Methicillin

penicillin V semisynthetic penicillin

withstands stomach acid > taken by mouth

Methicillin semisynthetic penicillin

first modified penicillin > resist effects of penicillinase

ampicillin semisynthetic penicillin

First penicillin to provide broad spectrum coverage for bacteria infections

Nafcillin

semisynthetic penicillin

narrow spectrum > alternative to methicillin that resists penicillinase

Cloxacillin semisynthetic penicillin

broad spectrum and resistant to penicillinase

Ticarcillin semisynthetic penicillin

extended spectrum > effective against gram neg rods

Aminoglycosides > targets the prokaryotic ribosome

what sites they bind to and what do they do to stop translation?

bind to 30s ribosomal subunit

• lead to misreading of mRNA = prevent translation

Chloramphenicol

> targets the prokaryotic ribosome

what sites they bind to and what do they do to stop translation?

• binds to 50S ribosomal subunit

  • prevents peptide bond formation during translation

Oxazolidinones

> targets the prokaryotic ribosome

what sites they bind to and what do they do to stop translation?

• binds to 50S ribosomal subunit

  • prevents initiation + block ribosomes assembly

Tetracyclines

> targets the prokaryotic ribosome

what sites they bind to and what do they do to stop translation?

• binds to 30S ribosomal subunit

  • prevents attachment of tRNA in translation > no protein synthesis

Erythromycin

• binds to 50S ribosomal subunit

  • prevents movement of ribosome along mRNA

MORE IN DEPT sulfa drugs and how they work

inhibiting bacterial folic acid synthesis = acting as competitive inhibitors of the enzyme dihydropteroate synthase (DHPS

how drug resistance develops in bacteria.

due to diverse genetic variations within a population and adaptability of microbial population

• can be inherent

side effects of certain antibiotics: tetracycline

• Gastrointestinal Issues – Nausea, vomiting, diarrhea.

• Tooth Discoloration in children – Permanent yellow/brown staining in children under 8.

• Pregnant women: effect fetal bones + teeth

 side effects of certain antibiotics: chloramphenicol.

• Bone Marrow Suppression (fewer red blood cells): Aplastic anemia

• Toxic to human cells

Antimalarial drugs > does curtis question mean

Target Plasmodium spp

quinine, chloroquinine, mefloquine, dozycycline

Antiprotozoal drugs > Multiple question short term

Target protozoan parasites

metronidazole, quincrine, sulfonamides, tetracyclines

Anthelminthic drugs

what does Piperazine and Niclosamide do

Target parasitic worms by immobilizing, disintegrating, or inhibiting metabolisms

Piperazine: paralyze muscles

Niclosamide: destroys scolex

What are nucleotide and nucleoside reverse transcriptase inhibitors and what do they inhibit / why important

inhibitors (NRTIs & NtRTIs) are antiviral drugs that inhibit the enzyme reverse transcriptase

• First-line treatment for HIV/AIDS.

• Prevent viral replication

• reverse transcriptase

enzyme found in retroviruses, such as HIV and Hepatitis B virus (HBV)

• crucial role in the replication of these viruses by converting viral RNA into DNA.

Antiretroviral drugs vs Antiviral drug

Antiretroviral designed to treat infections caused by retroviruses, particularly HIV

Antiviral drugs are a broader category of medications used to treat infections caused by viruses in general

superinfection

secondary infection that occurs in a host already infected with a different pathogen due to a disruption in normal flora > overgrowth of pathogens

• hard to treat bec pathogens are resistant to treatment used for primary infection

normal flora / what can disrupt this?

reside on or within a healthy human body without causing disease

Antibiotics can disrupt the balance of normal flora, allowing some microbes to overgrow and cause disease.

Kirby Bauer Test

REASON: tells you what antibiotic work + showing us resistance

1. pure bacterial culture is grown > then swab all over a plate

2. paper disk with antibiotics is placed on the surface

3. zone of inhibition around disk = antibiotics work

4. little to no zone = bacteria is resistant

MIC test aka tube dilution test

Minimum Inhibitory Concentration test

REASON: determines the lowest concentration required to inhibit the growth of a particular microorganism

• The test involves exposing bacteria to a range of antibiotic concentrations in a broth or agar medium.

• The lowest concentration that inhibits visible bacterial growth is identified as the MIC.

therapeutic index (TI)

the ratio of the dose of the drug that is toxic to humans as compared to its minimum effective dose

HIGH INDEX IS THE BEST

bec….dose amount required to be effective is also less harmful

LOW Index is the worst

effective dose is high so the toxicity of dose is large

TI= Dose toxic to patient​ / Dose effective against microbe

Who discovered the first penicillin

what was the first penicillin

Alexander Fleming

Penicllin G

Mefloquine, Quinine, Chloroquine (antimalarial drugs)

interfering with the malaria parasite's natural detoxification process of heme to hemozoin

Doxycycline (antimalarial drugs)

Doxycycline is a tetracycline that targets the 30S ribosomal subunit.inhibits protein synthesis by binding to the 30S ribosomal subunit

Quinacrine (antiprotzoal drug)

disrupting replication and transcription of DNA