Stool Culture

Test ID: 

705879

CPT code:

87045, 87046, 87427

Synonyms:

Culture, Stool, Comprehensive

Enteric Pathogens Culture, Routine

Feces Culture, Routine

Routine Culture, Stool

Clinical Use:

Detect bacterial pathogenic organisms in the stool; diagnose typhoid fever, enteric fever, bacillary dysentery, Salmonella infection.
Indications for stool culture include:
• Bloody diarrhea
• Fever
• Tenesmus
• Severe or persistent symptoms
• Recent travel to a third world country
• Known exposure to a bacterial agent
• Presence of fecal leukocytes

Test Information:

In enteric fever caused by Salmonella typhi, S choleraesuis, or S enteritidis, blood culture may be positive before stool cultures, and blood cultures are indicated early; urine cultures may also be helpful.
Diarrhea is common in patients with the acquired immunodeficiency syndrome (AIDS). It is frequently caused by the classic bacterial pathogens as well as unusual opportunistic bacterial pathogens and parasitic infestation. (Giardia, Cryptosporidium, and Entamoeba histolytica frequently reported.) Cryptosporidium, Isospora, and Pneumocystis can occur with AIDS. Rectal swabs are useful for the diagnosis of Neisseria gonorrhoeae and Chlamydia infections. AIDS patients are also subject to cytomegalovirus, Salmonella, Campylobacter, Shigella, C difficile, herpes, and Treponema pallidum gastrointestinal tract involvement.
In acute or subacute diarrhea, three common syndromes are recognized: gastroenteritis, enteritis, and colitis (dysenteric syndrome). With colitis, patients have fecal urgency and tenesmus. Stools are frequently small in volume and contain blood, mucus, and leukocytes. External hemorrhoids are common and painful. Diarrhea of small bowel origin is indicated by the passage of few large volume stools. This is due to accumulation of fluid in the large bowel before passage. Leukocytes indicate colonic inflammation rather than a specific pathogen. Bacterial diarrhea may be present in the absence of fecal leukocytes and fecal leukocytes may be present in the absence of bacterial or parasitic agents (ie, idiopathic inflammatory bowel disease). Although most bacterial diarrhea is transient (1 to 30 days) cases of persistent symptoms (10 months) have been reported. The etiologic agent in the reported case was Shigella flexneri diagnosed by culture of rectal swab. In infants younger than one year of age, a history of blood in the stool, more than 10 stools in 24 hours, and temperature greater than 39°C have a high probability of having bacterial diarrhea. Diarrhea is also a common side effect of long-term antibiotic treatment. Although often associated with Clostridium difficile, other bacteria and yeasts have been implicated.

Specimen Type:

Stool or rectal swab

Requested Volume: 

1 g, 1 mL

one swab in stool C&S transport vial (usual bacterial swab transport is not acceptable although the swab may be used)

Container Type: 

Stool culture transport vial is required; diapers are not acceptable. Culture collection swab may be used to collect rectal swabs or a swab of fecal material, then swab should be placed in stool culture transport vial (Para-Pak® C&S orange).

Collection:

A single stool specimen cannot be used to rule out bacteria as a cause of diarrhea. It is recommended that two or three stool specimens, collected on separate days, be submitted to increase the probability of isolating a bacterial pathogen. Hospitalized patients who develop diarrhea while hospitalized and more than 72 hours after admission should be tested for Clostridium difficileby detection of either toxin A and/or toxin B.
Studies have shown that patients who did not have gastroenteritis or other GI symptoms on admission are unlikely to have diarrheal illness due to Salmonella, Shigella, Campylobacter, or enterohemorrhagic E coli.
Stool: Specimen should be collected in sterile bedpan, not contaminated with urine, residual soap, or disinfectants. Those portions of stool that contain pus, blood, or mucus should be transferred to a sterile specimen container
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.
Stool specimen can be divided for other types of cultures by the laboratory. Miscellaneous tests and ova and parasites tests should be split into appropriate containers and transport devices prior to shipping to the laboratory.

Storage Instructions:

Maintain specimen at room temperature.

Expected Turnaround Time:

1 to 2 Days

Rejection Criteria

Specimen received in grossly leaking transport container; diapers; dry specimen; specimen submitted in fixative or additive; specimen received in expired transport media or incorrect transport device; inappropriate specimen transport conditions (not in a C&S vial or in an overfilled C&S vial); specimen received after prolonged delay in transport (usually more than 72 hours); specimen stored or transported frozen; wooden shaft swab in transport device; unlabeled specimen or name discrepancy between specimen and request label