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Stool Culture, Vibrio spp.

Fresh random stool, rectal swab if stool is unavailable.

Aim of the test
Isolate Vibrio cholera from stool specimen and perform antibiotic sensitivity testing.
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.



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