Aim of the test
Types of specimen
Fresh random stool, rectal swab if stool is unavailable.
Criteria of specimen rejection
Specimens received in grossly leaking Transport containers; diapers; dry specimens; specimens submitted in fixative or additives; specimens received in expired transport media or incorrect transport device; inappropriate specimen transport conditions (not in a C and S vial or in an overfilled C and S vial); specimens received after prolonged delay in transport (usually more than 72 hours); specimens stored or transported frozen; wooden shaft swab in transport device; unlabeled specimen or name discrepancy between the specimen label and the request
Specimen collection
The stool should be collected in sterile bedpan. A sample is transferred with the stick to the container. The specimen should contain at least 5 g of feces and, if present, those parts that contain blood and/or mucus should be selected. The specimen should not be contaminated with urine. Close the lid.
Rectal swab: Pass swab beyond anal sphincter, carefully rotate, and withdraw. Swabbing of lesions of rectal wall or sigmoid colon during proctoscopy or sigmoidoscopy is preferred.
Duodenal or sigmoid aspirate: Specimen should be collected by a physician trained in this procedure
Time relapse before processing the sample: Stool samples should be examined and cultured as soon as possible after collection.
Storage: Maintain specimen at room temperature until shipment.
Media
- Alkaline peptone water
- TCBS (Thiosulfate Citrate Bile salt Sucrose Agar)
Culturing procedure
A loopful of stool is streaked onto the surface of a TCBS plate and about one gram is inoculated into a tube containing alkaline peptone water, incubate at 37 °C. After 6-8 hours make a subculture from the alkaline peptone water onto the surface of a new plate of TCBS. Incubate at 37 °C for 24 hours.
Interfering factors
- Patient on antibiotic therapy.
- Improper sample collection.
Result reporting
A positive report will be issued only in case Vibrio cholera were isolated, otherwise, a negative report will be issued.
Turnaround time
Negative results are sent out 72 hours after receipt of the specimen. Results of positive cultures can be expected in 4-5days.
