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Useful For
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Detection of the presence of bacterial pathogens causing gastroenteritis.
Note: This test does not include detection of C.difficile.
Most acute diarrheal episodes in previously healthy immunocompetent people are mild, self-limiting, of viral or unknown etiology and laboratory investigation is generally not warranted.
Stool culture for diarrheal illness should be considered in the following situations:
- Temperature of >38.5°C,
- Immunocompromised patient.
- Persistent diarrhea(that lasts 14-29 days).
- Bloody diarrhea.
- When patient is systemically unwell (signs of dehydration )
- Non diarrheal symptoms of enteric fever, noninfectious and extraintestinal manifestations associated with enteric pathogens after consultation with a microbiologist.
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Method name and description
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Conventional culture technique
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Clinical information
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The World Health Organization defines diarrhea as passage of 3 or more loose or liquid stools per 24 hours, or more frequently than is normal for an individual person . Diarrhoea may be associated with symptoms such as abdominal cramps, nausea, malaise, vomiting, fever and dehydration. Frequent passing of formed stools is not diarrhea, nor is passing of loose, “pasty” stools by infants consuming human milk.
Diarrhea may be caused by several agents (e.g., bacteria, viruses, parasites, and chemicals) and these agents may result in similar signs and symptoms. A thorough patient history covering symptoms, severity, duration of illness, age, travel history, food consumption, history of recent antibiotic use, and illnesses in the family or other contacts may help with categorization of the disease. Culture of stool assists in the diagnosis when an infective bacterial etiology is suspected.
Types of diarrhea:
1. Acute watery diarrhea (includes cholera) and acute bloody diarrhea (includes dysentery, which manifests as frequent scant stools with blood and mucus) that lasts <7 days. Acute vomiting and/or diarrhea, often referred to as acute gastroenteritis.
2. Prolonged diarrhea that lasts 7–13 days.
3. Persistent diarrhea that lasts 14–29 days.
4. Chronic diarrhea that lasts 30 days or longer. Chronic diarrhoea is a major clinical feature and a leading cause of morbidity and mortality in uncontrolled HIV infection. Organisms implicated are predominantly parasites – Giardia species, Cryptosporidium species, Cyclospora cayetanensis and Microsporidia species.
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Aliases
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- Stool Culture
- Campylobacter Culture
- Salmonella Culture
- Shigella Culture
- Vibrio spp. Culture
- Yersinia enterocolitica Culture
- C Stool
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Specimen type / Specimen volume / Specimen container
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Specimen type
Specimen Volume
Specimen container
- Clean leak proof container
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Collection instructions / Special Precautions / Timing of collection
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Collection instructions
Adults and older children:
- Wash hands before collection. Put on gloves if necessary.
- Urinate before collecting stool.
- Collect specimen in a clean bed pan or use plastic wrap placed between the toilet seat and the bowl ( to prevent feces falling into toilet water).
- Collect the stool into the labelled container using the spoon provided with container or any disposable spoons (Sample areas of the specimen which appear bloody, slimy or watery).
- Close the lid tightly and place in biohazard bags provided.
- Flush the remaining stool down the toilet and dispose the plastic wrap or pan.
- Wash hands after collection.
Infants and Toddlers
- Infants - Take the stool out of the diaper. If your child has loose or runny stools, put the plastic side of the diaper next to the skin long enough to collect stool from it.
- Toddlers - If your toddler is toilet trained, you can use a clean, dry training potty, training pants, or a diaper to collect the stool.
Special precautions
- Do not submit feces contaminated with urine, soap or toilet water
- Ensure adequate amount of stool is collected and the container lid is screwed tightly after collection to prevent leakage.
- Do not collect stool from the toilet bowl.
- Do not defecate directly into stool container as this may contaminate the container increasing chances of infection spread.
- Try not to spill the stool on the outside of the specimen container.
- Do not use toilet paper to collect stool. Toilet paper may be impregnated with barium salts, which are inhibitory for some fecal pathogens.
(Note for users ordering his test on Cerner: Avoid reactivating old ON HOLD requests with irrelevant clinical history not reflecting present illness. Create a NEW order for the present illness)
Timing of collection
- Collect as soon as possible after onset of symptoms.
- Collect specimens before antimicrobial therapy wherever possible.
- Food handlers: Three samples on three consecutive days will be required.
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Relevant clinical information to be provided
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Please ensure all relevant clinical information has been provided with the test request to facilitate appropriate laboratory testing. The laboratory may add aditional tests based on the clinical information provided e.g. selective media for Vibrio, Yersinia, Campylobacter in suspected food poisoning, Shiga toxin assay for suspected Hemolytic uremic syndrome (HUS).
- Date of onset of diarrhea
- Severity, frequency and duration of diarrhea and if bloody diarrhea
- Clinical symptoms like vomiting, abdominal pain, fever
- Immune status (if immunocompromised)
- Travel history including location and date (where applicable)
- Similar illness in the family or other contacts
- If patient is part of an outbreak
- Food consumption ( for suspected food poisoning)
- History of recent antibiotic use
- If patient is a food handler
- Specify suspected target organisms, if clinical history warranted.(eg. cholera)
- Specify HUS (Hemolytic uremic syndrome) if suspected
- Any recreational/untreated water exposure
- Any animal exposure/contact
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Storage and transport instructions
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- ≤2 hrs. at room temperature (15-25°C)
- If transport is delayed, then refrigerate at 2-8°C and send to the laboratory within 24 hrs of collection
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Specimen Rejection Criteria
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- No relevant clinical details provided with the request. (Please note that where applicable, the relevant clinical details should reflect those on the patient’s electronic record at the time the order was placed).
- Samples sent with reactivated on hold orders old orders (for orders placed on Cerner)
- Improper container
- Leaking specimen
- Unlabeled/Mislabeled specimen
- Quantity not sufficient.
- Obvious contamination with urine, soap water or toilet paper
- Stool with barium
- Formed or Hard solid stools (Exemption outbreak investigation, Food handlers)
- Duplicate samples within 72 hrs except for HMC food handlers.
- Samples from food handlers not employed by HMC
- Follow up stool samples for previously positive cases
- Samples collected as routine for the next follow up visit. (IBD, Outpatient Clinic, Colonoscopy) unless discussed with Clinical Microbiologists
- Specimens from inpatients after the third hospital day, without prior consultation with Microbiology.(Exceptions: NCCCR patients, HIV patients and outbreak investigation initiated by infection control)
- Rectal bleeding ,Hemorrhoids, Anal fissures.
- Chronic diarrhea (that lasts 30 days or longer) without prior consultation (except HIV, Febrile neutropenia).
- Test of cure without prior consultation with a clinical microbiologist (Exemption when initiated by Public Health Department, HMC Food handlers).
- Non-infectious and extraintestinal manifestations associated with enteric pathogens without prior consultation with a clinical microbiologist.
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Biological reference intervals and clinical decision values
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Negative result
No Salmonella and no Shigella isolated.
If additional pathogens other than Salmonella and Shigella have been cultured for, then additional results will be released including:
- No Campylobacter spp isolated
- No Enteropathogenic E. coli isolated
- No Enterohemorrhagic E. coli isolated
- No Vibrio cholera isolated.
- No Aeromonas/Plesiomonas isolated
- No Yersinia spp isolated
- No Staph.aureus/No bacillus isolated (Food poisoning cases)
Where no organism is isolated from the sample, these will be reported as 'No growth'.
Positive result
All significant pathogens will be identified to species level.
Antimicrobial susceptibility testing will be performed in accordance with the criteria listed below.
- Salmonella typhi and Salmonella paratyphi A, B and C
- Shigella- all species
- Immunocompromised patients including AIDS patients
- Infants<1 year of age
- Elderly (>65 years of age)
- Pregnancy
- Food handlers
- At the request of physician e.g.for severe or prolonged infection or treatment failure.
- Selectively performed for other enteric pathogens after discussion with a clinical microbiologists.
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Factors affecting test performance and result interpretation
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- Improper transportation
- Improper handling
- Improper container
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Turnaround time / Days and times test performed / Specimen retention time
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Turnaround time
Days and times test performed
- Sunday to Thursday (7am-3pm) at HGH Microbiology Laboratory)
Specimen retention time
- 48 hrs. after final report released
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