SELECT AND USE MEDICATIONS

Antimicrobial Selection and Stewardship

Antimicrobial prescribing begins with establishing whether the patient has an infection that will benefit from treatment. Drug selection follows assessment of the clinical syndrome, likely pathogens, illness severity, infection site, and patient-specific risks.

The initial prescription is one part of a treatment process that includes diagnostic testing, reassessment, adjustment, and patient education (Ratliff & Oliphant, 2026).

Establish the Clinical Problem

Infection involves microbial activity associated with a host response or tissue injury. Colonization describes organisms present without attributable disease. Contamination occurs when organisms enter a specimen during collection or processing.

A positive culture therefore requires clinical interpretation. Bacteriuria in a patient without urinary symptoms, for example, should not automatically trigger treatment. Similarly, organisms recovered from a superficial wound may not identify the cause of a deeper infection.

Assess symptoms, examination findings, vital signs, organ function, and the reliability of the specimen. Immunosuppression and older age may alter typical manifestations. Consider noninfectious explanations such as inflammatory disease, thrombosis, medication reactions, or malignancy when findings are inconsistent with infection (Ratliff & Oliphant, 2026).

Obtain Useful Diagnostic Information

Collect specimens from the suspected infection site when the results are likely to change management. Appropriate collection technique and timing reduce misleading results.

When feasible, obtain indicated cultures before antibiotics. This should not create a clinically important delay in a patient with suspected sepsis or another time-sensitive infection.

Use microbiologic results alongside the clinical course. Susceptibility testing identifies potential activity under laboratory conditions; effective treatment also requires an appropriate dose, tissue exposure, and source control.

Choose Empiric Treatment

Empiric therapy targets the organisms most likely to cause the syndrome before definitive results are available. Selection should account for:

  • Infection site and severity
  • Previous cultures and resistant-organism history
  • Recent antimicrobial exposure
  • Local susceptibility patterns
  • Community, healthcare, travel, and environmental exposures
  • Allergy phenotype, kidney and liver function, pregnancy, and interactions

An antibiogram describes susceptibility among a defined collection of isolates. It does not establish the susceptibility of the individual patient’s organism. Population, specimen source, and collection setting affect its applicability (Ratliff & Oliphant, 2026).

Individualize Exposure and Source Control

An active medication can fail when it does not reach the affected tissue. Nitrofurantoin’s role in lower urinary infection, for example, does not extend to renal parenchymal infection.

Dose, route, interval, and duration should reflect the infection and the patient’s physiology. Reassess dosing when kidney function changes rather than assuming the admission value remains applicable.

Drainage of an abscess, relief of obstruction, removal of an infected device, or debridement may be essential. Increasing antimicrobial breadth cannot compensate for an untreated source (Ratliff & Oliphant, 2026).

Reassess and Narrow Treatment

Establish responsibility for reviewing pending results and contacting the patient. At reassessment, determine whether:

  • The diagnosis remains likely.
  • Symptoms and physiologic findings are improving.
  • Culture results permit narrower treatment.
  • The prescribed dose remains appropriate.
  • Oral therapy can replace intravenous therapy.
  • An adverse effect or access problem is interfering with treatment.
  • The planned duration remains justified.

Failure to improve should prompt evaluation of diagnosis, susceptibility, adherence, absorption, exposure, complications, and source control. Automatic escalation to a broader drug may conceal the actual problem (Ratliff & Oliphant, 2026).

Explain the Plan to the Patient

Provide a specific symptom-management and follow-up plan when antibiotics are not indicated. When prescribing, explain the indication, administration instructions, expected response, adverse effects, and reasons to seek reassessment.

Mason et al. (2018) found gaps in public understanding of antibiotics and resistance in a Greater London survey. Pharmacist counseling was associated with better knowledge in some areas. Because the study was cross-sectional, it does not establish that counseling caused the difference. Its practical contribution is the need to assess understanding rather than assume that previous prescriptions or public campaigns have prepared patients to use antibiotics appropriately.

Improve Prescribing at the Practice Level

Outpatient stewardship includes organizational commitment, changes to prescribing practice, measurement and feedback, and access to education and expertise (Sanchez et al., 2016).

A focused improvement project should define a population, numerator, denominator, target, and review interval. For example, measure the percentage of eligible adult visits for uncomplicated acute bronchitis that result in an antibiotic prescription each month, stratify results to detect inequities, and pair the outcome with balancing measures such as seven-day return visits, emergency evaluation, and hospitalization. Audit and feedback should identify whether diagnostic documentation, first-line selection, or duration is driving the result rather than treating total prescribing volume as sufficient evidence of quality.

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References

Mason, T., Trochez, C., Thomas, R., Babar, M., Hesso, I., & Kayyali, R. (2018). Knowledge and awareness of the general public and perception of pharmacists about antibiotic resistance. BMC Public Health, 18, Article 711. https://doi.org/10.1186/s12889-018-5614-3

Ratliff, A., & Oliphant, C. (2026). Patient assessment, antimicrobial selection, and stewardship. In M. A. Chisholm-Burns, P. M. Malone, J. M. Kolesar, K. C. Lee, P. B. Bookstaver, & K. R. Matthias (Eds.), Pharmacotherapy principles & practice (7th ed.). McGraw Hill.

Sanchez, G. V., Fleming-Dutra, K. E., Roberts, R. M., & Hicks, L. A. (2016). Core elements of outpatient antibiotic stewardship. MMWR Recommendations and Reports, 65(6), 1–12. https://doi.org/10.15585/mmwr.rr6506a1