Principles of Antimicrobial Treatment: Guidelines for Effective Therapy

When beginning antimicrobial therapy, you must be precise because if medications are overused in the community, the organism may become resistant. Among the most often given drugs in primary and secondary care are antibiotics.

At any given time, around one-third of all inpatients are undergoing antimicrobial therapy. When thinking about antimicrobial treatment, it's a good idea to follow a few fundamental guidelines to make sure that prescriptions for needless medication are limited.

Identification Of The Source Of Infection

Ideally, doctors shouldn't administer antibiotics until a certain clinical source has been found.  If the source has not yet been determined, stopped administering antibiotics.  A thorough clinical examination and assessment of the likelihood of a bacterial infection are crucial in this.
When diagnosing suspected deep-seated infections, like brain abscesses, imaging is a crucial component of the procedure.

Give the IV antibiotics and drain the abscess. The abscess itself lacks adequate vascularity, hence medication penetration will be ineffective.

If you only administer antibiotics, even via IV, the infection won't go away unless the incision and drainage are the source of the illness.

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Appropriate Sampling

The collection of clinical samples from the presumed infection focus is necessary prior to initiating antimicrobial medication.

Antibiotics can be given as soon as you remove the abscess fluid. The culture will be sterile after antibiotics are started. Therefore, if the patient is septic, at least one set of blood cultures should be obtained peripherally and from any vascular access devices that may be present.

Always take a sample prior to initiating antibiotics.In certain situations, if a deep infection is evident and the patient is stable, antimicrobial therapy may be postponed until a diagnostic tap or drainage can be carried out in order to optimize the likelihood of recovering the causal organism.

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Source Control

If an abscess or collection is found to be the source of the infection, it should be drained as soon as possible because abscesses are not vascularized and antimicrobials, even when administered intravenously, have extremely poor penetration into the cavity.

The removal of foreign material, which is not perfused and may harbor bacteria in a sticky polysaccharide matrix known as a biofilm, may be crucial to the success of treatment if the infection involves prosthetic material or a device. • The recovery of organisms is more likely to occur if a volume of pus in a sterile container is sent to the laboratory rather than a swab.

Also Read: Fungal Infections Seen In Ent Clinical Practice

Choice Of Initial Antimicrobial Agent

Targeting the most likely causal agents of a clinical condition is the goal of empirical antibiotic therapy.Since local rules will take into account patterns of resistance within the community, they should be followed. Every location has certain common bacteria, and each region has a unique resistance. Observe the community's local susceptibility.

Empirical broad-spectrum cover should ideally be avoided as it may obstruct a microbiological diagnosis and disturb the normally protective gut flora.

It is strictly forbidden to administer meropenem, imipenem, and vancomycin as the first line of treatment.  Adding a quickly bactericidal drug to the regimen should be taken into consideration for a patient whose condition is suspected to be bacteremia.

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Appropriate Dosing

 The likelihood of a disease cure is increased when the right antibiotic is administered in the right dosage.  It might stop resistance from arising from antimicrobial exposure at subtherapeutic concentrations.  Dosage modifications in antimicrobial treatment may be necessary for a number of reasons.  Many types of antibiotics require dose changes for patients with renal impairment and low creatinine clearance.

The dosing of antibiotics in the morbidly obese is a particular example, where regular dosing may not result in the accomplishment of therapeutic serum or tissue levels. • The dosage of aminoglycosides and glycopeptides is often adjusted to the patient's body weight and creatinine clearance.

Route Of Administration

Coral antibiotic therapy is often all that is needed for many simple infections, particularly in the primary care context.  Topical antimicrobials alone may be appropriate, for instance, in the treatment of moderate otitis externa, depending on the source of infection.

If the patient exhibits signs of systemic distress in addition to the infection and sepsis is suspected, the patient may have bacteremia, in which case intravenous antibiotic treatment should be started.
A suitable intravenous antibiotic should always be used to treat bacteriaemia. The length of the intravenous treatment may vary depending on the organism and the underlying cause of infection.

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De-escalation And Switch To Oral Administration Of Treatment

Antimicrobial therapy should be modified in accordance with the organism's susceptibility once culture results are obtained.  The administration route should be reevaluated at the latest 48 hours after therapy has started via the intravenous route and clinical improvement is noted.

As long as blood cultures came back negative and oral therapy was suitable for the infection cause, switching to oral antimicrobials was taken into consideration.

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Completing A Course Of Treatment

Taking an antibiotic for the recommended length of time increases the likelihood that the illness will be cured. It also lowers the chance of recurrence and the need for additional courses of probably larger spectrum antibiotics.

In general, deep-seated infections and infections in polyvascularized tissue, such as cartilage and bone, will require extended courses of treatment with agents that can penetrate these tissues to reach therapeutic levels. The duration of the course will vary between different foci. It will also depend in part on the organism involved.

Hope you found this blog helpful for your Basic Sciences Preparation. For more informative and interesting posts like these, keep reading PrepLadder’s blogs. 

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