Bacterial Culture (Throat, Urine, Blood, Wound)
Definition
The collected sample is placed in a special growth medium in the laboratory that allows bacteria to multiply; the resulting bacterial cells are used to determine which bacterium is present.
Purpose
Determines whether a bacterial infection is present and which bacterium is causing it. The sample type varies depending on the infection being investigated:
| Culture | Sample | What it looks for |
|---|---|---|
| Throat culture | Swab from the back of the throat and tonsils | Streptococcal throat infection |
| Urine culture | Sterile urine sample | Urinary tract infection |
| Sputum culture | Sputum coughed up (or obtained by bronchoscopy if needed) | Pneumonia, tuberculosis |
| Blood culture | Blood from a vein | Bloodstream infection |
| Stool culture | Stool | Digestive system infection, food poisoning |
| Wound culture | Swab or tissue from an open wound | Wound infection |
Results
A positive result indicates a bacterial infection and identifies the causative agent. The physician usually then orders an antibiogram to determine which antibiotic will be effective.
Risks and Limitations
Results usually come back in 1 to 2 days; some bacteria take 5 days or longer to grow sufficiently.
Do not use antibiotics if your result shows this is not a bacterial infection. Unnecessary antibiotic use leads to resistance and makes treating infections harder.