Cell wall synthesis inhibitors: Cephalosporins

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Cell wall synthesis inhibitors: Cephalosporins

Prerequisite basic sciences

Prerequisite basic sciences

Attributable risk (AR)

Bias in interpreting results of clinical studies

Bias in performing clinical studies

Clinical trials

Confounding

DALY and QALY

Direct standardization

Disease causality

Incidence and prevalence

Indirect standardization

Interaction

Mortality rates and case-fatality

Odds ratio

Positive and negative predictive value

Prevention

Relative and absolute risk

Selection bias

Sensitivity and specificity

Study designs

Test precision and accuracy

Acyanotic congenital heart defects: Pathology review

Adrenal masses: Pathology review

Bacterial and viral skin infections: Pathology review

Bone tumors: Pathology review

Coagulation disorders: Pathology review

Congenital neurological disorders: Pathology review

Cyanotic congenital heart defects: Pathology review

Extrinsic hemolytic normocytic anemia: Pathology review

Eye conditions: Inflammation, infections and trauma: Pathology review

Eye conditions: Refractive errors, lens disorders and glaucoma: Pathology review

Headaches: Pathology review

Intrinsic hemolytic normocytic anemia: Pathology review

Leukemias: Pathology review

Lymphomas: Pathology review

Macrocytic anemia: Pathology review

Microcytic anemia: Pathology review

Mixed platelet and coagulation disorders: Pathology review

Nasal, oral and pharyngeal diseases: Pathology review

Nephritic syndromes: Pathology review

Nephrotic syndromes: Pathology review

Non-hemolytic normocytic anemia: Pathology review

Pediatric brain tumors: Pathology review

Pediatric musculoskeletal disorders: Pathology review

Platelet disorders: Pathology review

Renal and urinary tract masses: Pathology review

Seizures: Pathology review

Viral exanthems of childhood: Pathology review

Pharmacodynamics: Agonist, partial agonist and antagonist

Pharmacodynamics: Desensitization and tolerance

Pharmacodynamics: Drug-receptor interactions

Pharmacokinetics: Drug absorption and distribution

Pharmacokinetics: Drug elimination and clearance

Pharmacokinetics: Drug metabolism

Prerequisite basic sciences

Growth hormone and somatostatin

Prerequisite basic sciences

Breastfeeding

Prerequisite basic sciences

Androgens and antiandrogens

Estrogens and antiestrogens

Miscellaneous cell wall synthesis inhibitors

Protein synthesis inhibitors: Tetracyclines

Cell wall synthesis inhibitors: Penicillins

Antihistamines for allergies

Acetaminophen (Paracetamol)

Non-steroidal anti-inflammatory drugs

Antimetabolites: Sulfonamides and trimethoprim

Antituberculosis medications

Cell wall synthesis inhibitors: Cephalosporins

Cell wall synthesis inhibitors: Penicillins

DNA synthesis inhibitors: Fluoroquinolones

DNA synthesis inhibitors: Metronidazole

Miscellaneous cell wall synthesis inhibitors

Miscellaneous protein synthesis inhibitors

Protein synthesis inhibitors: Aminoglycosides

Protein synthesis inhibitors: Tetracyclines

Bronchodilators: Beta 2-agonists and muscarinic antagonists

Bronchodilators: Leukotriene antagonists and methylxanthines

Pulmonary corticosteroids and mast cell inhibitors

Glucocorticoids

Bronchodilators: Beta 2-agonists and muscarinic antagonists

Bronchodilators: Leukotriene antagonists and methylxanthines

Azoles

Glucocorticoids

Pulmonary corticosteroids and mast cell inhibitors

Acetaminophen (Paracetamol)

Non-steroidal anti-inflammatory drugs

Antimetabolites: Sulfonamides and trimethoprim

Cell wall synthesis inhibitors: Cephalosporins

Cell wall synthesis inhibitors: Penicillins

Miscellaneous protein synthesis inhibitors

Protein synthesis inhibitors: Tetracyclines

Pharmacodynamics: Agonist, partial agonist and antagonist

Pharmacodynamics: Desensitization and tolerance

Pharmacodynamics: Drug-receptor interactions

Pharmacokinetics: Drug absorption and distribution

Pharmacokinetics: Drug elimination and clearance

Pharmacokinetics: Drug metabolism

Cell wall synthesis inhibitors: Cephalosporins

Glucocorticoids

Miscellaneous protein synthesis inhibitors

Anticonvulsants and anxiolytics: Barbiturates

Anticonvulsants and anxiolytics: Benzodiazepines

Nonbenzodiazepine anticonvulsants

Cell wall synthesis inhibitors: Cephalosporins

Cell wall synthesis inhibitors: Penicillins

Miscellaneous cell wall synthesis inhibitors

Assessments

Cell wall synthesis inhibitors: Cephalosporins

Flashcards

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Flashcards

Cell wall synthesis inhibitors: Cephalosporins

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External References

First Aid

2022

2021

2020

2019

2018

2017

2016

Ceftriaxone

Chlamydia spp. p. 146

Chlamydia trachomatis p. , 723

for gonococci p. 140

for Haemophilus influenzae p. , 140

mechanism and use p. 186

mechanism (diagram) p. 184

meningitis p. 177

meningococci p. 140

prophylaxis p. 195

typhoid fever p. 142

Gonorrhea

ceftriaxone p. 186

Lyme disease p. 144

ceftriaxone p. 186

Meningitis

ceftriaxone p. 186

Transcript

Cephalosporins are antibiotics which got their name from a mold known as cephalosporium, from which they were originally extracted.

They belong to the pharmacological group of beta-lactam antibiotics.

What all beta-lactams have in common is a beta-lactam ring in their structure, which gives them their name, and also the mechanism of action - which is the inhibition of cell wall synthesis in bacteria.

So, our body is made out of eukaryotic cells.

Bacterias belong to a different type of cells, called the prokaryotes.

From the outside to inside, they have a slimy capsule made out of polysaccharides.

Then, there’s a cell wall in most prokaryotes.

A cell wall is a structural layer, which encapsulates bacteria, and offers structural support and protection, like a suit of armor. It also offers some filtering capabilities, as not everything can pass freely through it.

Finally, on the inside, there’s a pretty standard cell membrane.

Should something happen to this wall, say, if its synthesis mysteriously stopped, its owner’s life expectancy will turn to that of a snowflake in Sahara. And that’s exactly what we’re hoping to do.

Bacterial cell walls are made of a substance called peptidoglycan, or murein.

Peptidoglycan is a very strong, crystal lattice resembling three-dimensional structure, composed out of long using “strands” of amino polysaccharides, running in parallel.

These are made of made out segments of N-acetylglucosamine, or NAG, and N-acetylmuramic acid, or NAM, in an alternating pattern - so, NAG, NAM, NAG, NAM, and so on, like a pearl necklace.

These strands are also cross linked by short, four to five amino acids long, or tetrapeptide chains, protruding from NAM subunits.

Those pentapeptides reach out and link to pentapeptide chains from the neighboring strands, for structural stability, a sub-process known as transpeptidation.

All of this is made possible by enzymes called DD-transpeptidases, that are also better known as penicillin binding proteins, or PBPs.

These enzymes are highly specialized to grab and hold two pentapeptide ends and fuse them together, creating a stable link between the two polysaccharide strands, essentially creating peptidoglycan.

If you imagine the enzyme as a “lock”, then the pentapeptide chain would be a key, so it fits perfectly in, and allows the enzyme to do its work.

In essence, all beta lactam antibiotics, like the cephalosporins, somewhat resemble the tetrapeptide chains.

Inside the bacteria, PBP enzymes will mistakenly bind to the beta lactams antibiotic molecule instead of a tetrapeptide and stick inside the PBP forever, like chewing gum in a keyhole, permanently disabling it.

As more and more of PBPs get disabled, the crosslinking fails to occur, and the wall becomes weak and unstable.

Sources

  1. "Katzung & Trevor's Pharmacology Examination and Board Review,12th Edition" McGraw-Hill Education / Medical (2018)
  2. "Rang and Dale's Pharmacology" Elsevier (2019)
  3. "Goodman and Gilman's The Pharmacological Basis of Therapeutics, 13th Edition" McGraw-Hill Education / Medical (2017)
  4. "Penicillin-Binding Proteins of Gram-Negative Bacteria" Clinical Infectious Diseases (1988)
  5. "Methicillin-resistant Staphylococcus aureus: A consensus review of the microbiology, pathogenesis, and epidemiology with implications for prevention and management" The American Journal of Medicine (1993)
  6. "A Comparison of Ceftriaxone and Cefuroxime for the Treatment of Bacterial Meningitis in Children" New England Journal of Medicine (1990)
  7. "Third-generation cephalosporins" Medical Clinics of North America (1995)
  8. "Summary of Ceftaroline Fosamil Clinical Trial Studies and Clinical Safety" Clinical Infectious Diseases (2012)
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