| Test: | Escherichia coli (Hemorrhagic) Culture, Stool, HECCU |
| Synonym: | Culture, Hemorrhagic E. coli; Culture, E. coli 0157: H7; Culture, Shigatoxin Positive E. coli, PFGE DNA fingerprinting |
| Method: | Standard Culture |
| Availability: | Daily; final report at 2 days for negatives. Positives are reported as soon as detected. |
| Specimen: | Preserved stool, isolates from shigatoxin positive stool on MacConkey or MacConkey with sorbitol media, or if preserved stool or isolates are not available, consider sending the MacConkey plate from the original stool culture that was shigatoxin positive |
| Collection Device: | Stool use enteric transport media (Cary-Blair media) |
| Volume: | 1 - 5 mL fresh stool or 10 mL in transport media |
| Storage/Transport: | Transport stool unpreserved at room temperature. If transport delayed > 2 hours, preserve stool in transport media (Category B Shipment). To send the MacConkey or MacConkey with sorbitol plate, tape the plate, place in biohazard bag, then white Tyvek envelope, and finally into a Category A shipping box and ship at room temperature. These shipping materials are provided by NPHL. (Category A shipment). |
| Unacceptable: | Non-sterile or leaking container, multiple specimens (more than 1 stool in a 24 hour period), dry specimens, delayed transport to lab without use of appropriate preservative, specimen in diapers. GN broth or MAC broth and Blood Agar media plates (BAP) are strongly discouraged due to low recovery. |
| Specimen Stability: | Fresh stool is stable at room temperature for up to 2 hours. Preserved stool in transport media is stable at room temperature for up to 48 hours, refrigerated for up to 4 days, and frozen for up to 1 week. |
| Reference Interval: | Unable to isolate a Shigatoxin-producing E. coli by culture for PFGE DNA fingerprinting. |
| Reportable Disease: | Positive result is reportable |
| Comments: | This test is generally performed to isolate a shigatoxin-producing E. coli from a stool that was EIA positive for shigatoxin following a routine stool culture (STOCU). Rarely, this test can also be performed for the primary detection of shigatoxin-positive E. coli in stool where an outbreak of shigatoxin-producing E. coli is suspected. This test should not be used for determination of proof-of-cure. Under this circumstance, stool should be tested using the shigatoxin EIA assay (SHIGA). All shigatoxin-positive stools (preserved in Enteric transport media, Cary-Blair transport media) should be sent to the NPHL for isolation of the shigatoxin positive E. coli for serotyping and DNA fingerprinting. If preserved stool or isolate is not available, the MacConkey or MacConkey with sorbitol plate from original stool culture with a positive shigatoxin result can be sent. Laboratories that isolate shigatoxin-positive E. coli from stool specimens should submit all isolates to the NPHL. These isolates will undergo DNA fingerprinting (PFGE) and if not already determined, serotyping. |
| Revised: | 3/1/2012 |