Susceptibility studies, antimicrobial agent; agar dilution method, per agent (eg, antibiotic gradient strip)
CPT4 code
Name of the Procedure:
Susceptibility Studies, Antimicrobial Agent; Agar Dilution Method
Common Name(s): Antibiotic Susceptibility Testing (Agar Dilution Method)
Summary
Susceptibility studies using the agar dilution method involve testing bacteria to determine their sensitivity to specific antibiotics. This helps in identifying the most effective antibiotic for treating infections caused by these bacteria.
Purpose
This procedure addresses bacterial infections by determining the most effective antibiotic for treatment. The goal is to identify which antibiotics can inhibit or kill the bacteria, ensuring effective treatment and minimizing the risk of antibiotic resistance.
Indications
- Persistent or severe bacterial infections not responding to initial treatments.
- Infections caused by bacteria known for antibiotic resistance.
- Clinical situations requiring targeted antibiotic therapy based on confirmed sensitivity.
Preparation
- No specific preparatory steps are typically needed for the patient as this is a laboratory procedure involving bacterial samples.
- Samples such as blood, urine, or swabs are collected based on the infection site.
Procedure Description
- A bacterial sample is placed on an agar plate containing different concentrations of the antibiotic.
- The plate is incubated to allow bacterial growth.
- Observations are made to see at which concentrations the bacteria were inhibited or killed.
- Results are analyzed to determine the minimum inhibitory concentration (MIC) of the antibiotic.
Tools: Agar plates, antibiotic solutions, incubators, and microbial growth assessment tools.
Sedation: Not applicable.
Duration
The entire process, from sample inoculation to results, typically takes 24 to 48 hours.
Setting
The procedure is performed in a microbiology laboratory.
Personnel
- Clinical microbiologists
- Laboratory technicians
Risks and Complications
- Minimal risks are associated with the procedure itself as it is lab-based.
- Potential complications arise from delayed results, impacting timely treatment decisions.
Benefits
- Accurate identification of the best antibiotic for treatment, leading to effective infection management.
- Helps in combating antibiotic resistance by avoiding the use of ineffective antibiotics.
- Results are usually available within 1-2 days.
Recovery
Not applicable as this is a laboratory procedure.
Alternatives
- Broth Dilution Method: Similar principle but uses liquid medium instead of agar plates.
- Automated Systems: Faster results but may be more expensive.
- Disk Diffusion Method: Another common method but less quantitative than agar dilution.
Patient Experience
The patient does not directly experience the procedure as it is conducted in a lab setting. The patient might feel relieved and hopeful upon receiving targeted and effective antibiotic treatment based on the susceptibility results.