Name of the Procedure:

Susceptibility Studies, Antimicrobial Agent; Disk Method, Per Plate (12 or Fewer Agents)

Summary

A laboratory test that determines the effectiveness of antibiotics against bacteria isolated from a patient's sample. This is done by placing small disks, each impregnated with a different antibiotic, onto a plate cultured with the bacteria.

Purpose

The procedure addresses bacterial infections by identifying the most effective antibiotics for treatment. The goal is to guide healthcare providers in selecting the best antimicrobial therapy for the patient.

Indications

• Persistent bacterial infections not responding to initial treatments
• Severe infections where immediate and appropriate antibiotic therapy is crucial
• Development of resistance in infections
• Immunocompromised patients with unusual or severe infections

Preparation

Generally, no special preparation is needed from the patient. If a sample needs to be collected (e.g., urine, blood, sputum), specific instructions will be provided, such as collection methods and timing.

Procedure Description

1. A sample containing bacteria (e.g., urine, blood, tissue) is cultured on an agar plate.
2. Once an adequate bacterial colony has grown, small paper disks impregnated with different antibiotics are placed on the agar.
3. The plate is incubated to allow bacterial growth and interaction with the antibiotics.
4. Zones of inhibition (areas where bacteria cannot grow) around the disks indicate the effectiveness of each antibiotic.
5. The size of these zones is measured and compared to standardized charts to determine susceptibility.

Duration

Typically, the incubation period ranges from 18 to 24 hours.

Setting

The procedure is performed in a laboratory setting.

Personnel

• Clinical Microbiologists
• Laboratory Technicians

Risks and Complications

• Minimal risk to the patient as this is an in vitro lab test.
• Delay in results can occur if bacteria require additional time to grow adequately.

Benefits

• Accurate identification of the most effective antibiotics.
• Timely and precise treatment of bacterial infections.
• Prevention of unnecessary use of broad-spectrum antibiotics.

Recovery

No recovery process is required for the procedure itself. Follow-up depends on the treatment plan based on the results.

Alternatives

• Automated susceptibility testing methods
• Broth dilution methods
• Each alternative has its advantages and limitations in terms of cost, time, and specificity.

Patient Experience

The patient will not directly experience the procedure since it is conducted in a lab setting. The benefits are realized through more targeted and effective antibiotic treatment.