Aerobic C&S Urine Culture - DD
Test Code
A130
Also Known As
No data available
Test Parameters Included
No data available
Department
MICROBIOLOGY
Methodology
Conventional Culture and Susceptibility Testing (Disk Diffusion - DD)
This test employs traditional or Conventional Culture methods for bacterial growth and Disk Diffusion (DD) for antibiotic susceptibility testing. The process involves:
* Manual Inoculation: The urine sample is manually inoculated onto appropriate culture media (e.g., Blood Agar, MacConkey Agar) using calibrated loops. This allows for semi-quantitation of bacterial growth.
* Manual Incubation: The inoculated plates are then incubated at a specific temperature (typically 35-37°C) for 18-24 hours.
* Colony Counting & Identification (ID): After incubation, laboratory technologists visually inspect the plates for bacterial growth. Significant growth is determined based on Colony Forming Unit (CFU) thresholds. If significant growth of a single, predominant organism is observed, the bacteria are identified using traditional microbiological methods (e.g., Gram staining, biochemical tests, API strips, or manual rapid identification systems) to determine the specific bacterial species.
* Disk Diffusion (Kirby-Bauer Method): Once the bacteria are identified, a standardized bacterial suspension is prepared and uniformly spread onto a Mueller-Hinton agar plate. Paper disks impregnated with a specific concentration of various antibiotics are then placed on the agar surface.
* Diffusion: The antibiotic diffuses from the disk into the agar, creating a concentration gradient.
* Incubation: The plate is incubated for 18-24 hours.
* Zone of Inhibition: If the antibiotic inhibits bacterial growth, a clear circular area (zone of inhibition) appears around the disk.
* Manual Interpretation: The diameter of the zone of inhibition is measured using a ruler or a zone reader. These measurements are then compared against standardized breakpoints (established by organizations like CLSI - Clinical and Laboratory Standards Institute) to determine if the isolate is Susceptible (S), Intermediate (I), or Resistant (R) to each tested antibiotic.
This conventional approach provides reliable results for bacterial identification and antibiotic susceptibility, guiding effective antibiotic therapy, though it can be more labor-intensive and slower than automated methods for MIC determination.
Sample Required
Urine (Mid-Stream Clean Catch or Catheterized)
* The preferred sample type is a mid-stream clean-catch urine specimen to minimize contamination from the skin and urethra. Patients are provided with clear instructions on how to collect this specimen.
* For hospitalized or specific patient populations, a catheterized urine specimen may be collected.
* First-morning urine is often preferred as it is more concentrated and likely to yield organisms if present.
* Minimum volume: Typically 5-10 mL of urine is sufficient.
* Sterile container: Urine must be collected in a sterile, leak-proof container.
* Timely transport/refrigeration: The specimen should be transported to the laboratory immediately or refrigerated (4°C) for up to 24 hours to prevent overgrowth of contaminants or degradation of pathogens.
Preparation
Proper collection and timely transport of the urine sample are paramount for accurate results to avoid contamination and bacterial overgrowth. * Patient Instructions: Provide the patient with clear, d... Read more
Schedule Report
72 Hours
Emergency Report
Yes
Frequently Asked Questions
No data available
Test Description
- High-end laboratory & medical equipment.
- Outstanding doctor team.
- Personalized care & high-quality service.
- Tailormade health screening packages.