Antibiotics

Bacteriostatic antibiotics inhibit bacterial replication, whereas bactericidal antibiotics directly kill bacteria.

Bactericidal antibiotics allow the host immune system to combat bacteria, whereas bacteriostatc antibiotics rely less on host immunity for clearing infection.

Bacteriostatic antibiotics are the preferred treatment for infections at sites of poor penetration.

Bacteriostatic and bactericidal antibiotics are very similar and can be used interchangeably.

bacteriostatic

bactericidal

bacteriostatic

bactericidal

bactericidal

bacteriostatic

A thick outer peptidoglycan layer with an inner lipid bilayer.

A thin outer peptidoglycan layer with an inner lipid bilayer.

An outer lipid bilayer containing porins. Lipoproteins attach the outer membrane to a middle peptidoglycan layer. The inner cytoplasmic membrane is a lipid bilayer.

An outer lipid bilayer. Lipoproteins attach the outer membrane to a middle peptidoglycan layer. The inner cytoplasmic membrane is a lipid bilayer that contains porins.

Gram negative bacteria have a thicker peptidoglycan layer in the cell membrane than gram positive bacteria, which makes it more difficult for antibiotics to penetrate the cell.

Gram negative bacteria have porins embedded in the outer membrane, which can block out certain antibiotics.

In fact, gram positive bacteria are more difficult to treat than gram negative.

Gram negative bacteria have a strong outer membrane and a peptidolgycan layer protecting the cytoplasmic membrane, whereas gram positive bacteria only have peptidoglycan layers covering the cytoplasmic membrane. This makes it more difficult for antibiotics to penetrate gram negative bacteria.

Gram negative bacteria possess exotoxins and endotoxins, whereas gram positive bacteria only possess exotoxins.

To determine the antibiotics to which the bacteria is most sensitive

To determine whether the bacteria is gram negative or gram positive

To determine whether the bacteria is a rod or coccus form

To determine how the bacteria associate

The MIC correlates to the dose that will be administered to the patient. We need serum and tissue concentrations to exceed the MIC to be effective.

The MIC will help to determine when therapy should begin and how long the course of treatment should be.

When calculating the MIC, you have to take into consideration the patient's age, disease state, previous antibiotic use, and other factors.

Immunosuppressed patients will always require a dose that is much lower than the MIC.

Not until C&S results are available.

As soon as there is a clinical suspicion of infection.

As soon as staining results are available and the bacteria is confirmed as gram positive or negative.

Whenever a patient is admitted to hospital. All patients should receive antibiotics prophylactically.

Antibiotics should never be combined because it increases the risk of toxicity and developing resistance.

Combining antibiotics may result in either an additive, synergistic, or antagonistic response, depending on the agents used and the bacteria being targeted.

Combining antibiotics will result in a synergistic response, which is why it is standard practice to administer combination therapy.

Combinations should never be administered to an immunosuppressed patient.

Beta-lactams target penicillin-binding proteins (PBPs), which are involved in the final stages of synthesis of peptidoglycan. Mammalian cells do not require this protein to synthesize cell wall components.

Beta-lactams are bacteriostatic so they do not actively kill cells.

Beta-lactams are quickly metabolized and excreted.

Certain bacteria that occur naturally in the body produce an enzyme that cleaves the beta-lactam ring, thereby inactivating the drug. This prevents levels of the drug from building up in the body and leading to toxicity.

Dosing is usually TID to QID because of short half-lives

Some have better absorption if taken on empty stomach (e.g. cloxacillin)

Most are renally excreted, therefore requiring dose adjustment in pts with renal impairment

Unlike many other antibiotics, they have no influence on the efficacy of oral contraceptives

bactericidal

bacteriostatic

You suspect an allergic reaction. You should stop the infusion immediately and notify the prescribing MD.

You suspect red man syndrome. You should slow the infusion rate and monitor the patient.

You suspect an allergic reaction. You should call the Rapid Response Team and document the event ASAP.

You suspect that these symptoms are caused by the infection. You should do nothing.

There is a continued inhibition of bacterial growth even when concentration falls below MIC

The patient may exhibit symptoms of toxicity even after the course of treatment has ended

The patient may experience adverse effects for days or weeks after treatment

The patient will experience GI troubles after a course of treatment because their gut flora is diminished

Because both agents are nephrotoxic

Because both agents may cause Stevens-Johnson syndrome

Because both agents have a very narrow therapeutic index

Because monitoring peak concentrations will give you false results

bactericidal

bacteriostatic

bactericidal

bacteriostatic

bactericidal

bacteriostatic

Sulfonamides

Vancomycin

Penicillins

Tetracyclines

bacteriostatic

bactericidal

Clindamycin

Vancomycin

Aminoglycosides

Tetracyclines

Metronidazole

Vancomycin

Tetracycline

Penicillin