Stool specimen

Unless ordered otherwise, the nurse should save all stools that are passed after the drug is given. It is important to visually inspect each stool for passage of the helminth. If stool specimens are to be saved for laboratory examination, the nurse follows hospital procedure for saving the stool and transporting it to the laboratory. If the patient is acutely ill or has a massive infection, it is important to monitor vital signs every 4 hours and measure and record fluid intake and output. The nurse observes the patient for adverse drug reactions, as well as severe episodes of diarrhea. It is important to notify the primary health care provider if these occur. 

Promoting an Optimal Response to Therapy The diagnosis of a helminth infection is made by examination of the stool for ova and all or part of the helminth. Several stool specimens may be necessary before the helminth is seen and identified. The patient history also may lead to a suspicion of a helminth infection, but some patients have no symptoms. 

Follow-up stool specimens will be necessary because this is the only way to determine the success of drug therapy. 

Stool specimens or perineal swabs are negative for parasites. 

Isolation is usually not necessary, but hospital policy may require isolation procedures. Stool precautions are usually necessary. The nurse washes the hands thoroughly after all patient care and die handling of stool specimens. 

DIARRHEA AND DEFICIENT FLUID VOLUME The nurse records the number, character, and color of stools passed. Daily stool specimens may be ordered to be sent to die laboratory for examination. The nurse immediately delivers all stool specimens saved for examination to die laboratory because the organisms die (and therefore cannot be seen microscopically) when die specimen cools. The nurse should inform laboratory personnel diat the patient has amebiasis because die specimen must be kept at or near body temperature until examined under a microscope... 

In most instances, C. difficile toxin testing of a single stool specimen effectively establishes the diagnosis. Various ELISA kits are available to detect toxin A or toxin B or both. Those that detect both toxin A and B are preferred. Repeated testing can boost sensitivity. 

Simplest method of diagnosis is detection of oocysts by modified acid-fast staining of a stool specimen. Standard ova and parasite test does not include Cryptosporidium. 

The three principal microscopic examinations performed on stool specimens are direct wet mount, wet mount after concentration, and permanent stain. Although each examination can contribute to diagnosis, the yield of some methods is small with certain kinds of specimens. As a minimum, formed specimens should be examined by a concentration procedure. Soft specimens should be examined by concentration and permanent stain, and, if submitted fresh, by direct wet mount. Loose and watery specimens should be examined by wet mount and permanent stain. If specimens are received in fixative and the consistency is not known, concentration and permanent stain should be performed. Other examinations may be helpful. Special procedures which may assist in the diagnosis of specific parasites are noted below in discussions of the parasites. 

The ability to coat paramagnetic beads with antibodies to surface antigens of bacteria has been exploited to separate and concentrate organisms from the sample. The bacteria can then be lysed, and the DNA released into the supernatant can be amplified by PCR. Such an approach has found a wide range of applications, among which is the detection of Helicobacter pylori in water and stool specimens (El). 

El. Enroth, H., and Engstrand, L., Immunomagnetic separation and PCR for detection of Helicobacter pylori in water and stool specimens. J. Clin. Microbiol. 33, 2162-2165 (1995). 

A 10-year-old girl in North Carolina has had abdominal pain and cramps for the past few days. Her examination produced normal findings except for nonspecific abdominal discomfort with a complete blood count showing anemia and 22% eosinophils (elevated). A stool specimen revealed the characteristic eggs of A. lumbricoides. The drug of choice in treating this is... 

Because the couple s residence had been severely damaged and flooded by Hurricane Rita, both patients had waded in coastal floodwaters in late September, 2 to 3 weeks before their illness onset. Five days before onset of illness, both had eaten locally caught crabs. On October 14, the day preceding illness onset, both had eaten shrimp purchased from a local fisherman. The shrimp were boiled for 5 minutes however, at least some of the boiled shrimp were returned to a cooler containing raw shrimp and were eaten later. Two other persons who ate the shrimp reported mild diarrhea and abdominal discomfort they did not seek medical attention, and no stool or serum specimens were collected from them for testing. Toxigenic V. cholerae was isolated at the hospital from stool specimens of the two patients and was confirmed at the Louisiana State Public Health Laboratory. 

The diagnosis of cryptosporidiosis is posed by observation of the oocysts in the feces of infected individuals. Routine stool examination used for most parasites usually fails to detect Cryptosporidium, however. Thus, a stool specimen is examined using staining techniques available for this parasite. See Figure 2.12. 

Amebiasis is diagnosed by finding the cysts of Entamoeba histolytica in a stool specimen examined under a microscope. Because the number of cysts in the stool can change from day to day, and cysts may not even be in every stool specimen, sometimes more than one stool specimen must be obtained for examination. A blood test is also available for detection of antibodies against the parasite. 

In 1994 N. Deka et al. detected virus-like particles of 27-37 nm in size in specimens of stools from French patients with virus hepatitis NANB. The authors provisionally named the infectious agent hepatitis French virus or HEV (509) The patients tested seronegative for other hepatitis viruses, and no HAV or HEV was detectable in the stool specimens. Following i.v. application of such particles in rhesus monkeys, the hepatitis virus was produced and could be identified in the liver cells and stools of these primates. The genetic material was characterized as a double-stranded DNA of 20 kilobases in length. It was possible to reproduce the pathogens in... 

Synthetic substrates are commonly used for this application. A sensitive kinetic assay has been developed that uses succ-ala ala-pro-phe-4-nitroaniiide as a substrate, and made commercially available. Prior treatment of the stool specimen with detergent to release particle-bomid CHY is necessary. A cheap device enables a small stool sample to... 

As mentioned above, many molecular assays detect rhi-noviruses and most will detect polioviruses. These two factors can lead to unexpected and misleading positive results when testing respiratory or stool specimens. The diagnosis of enterovirus meningitis should be based on testing of CSF specimens, while sepsis syndrome in the neonate is best made by testing serum, plasma, or CSF samples. 

Bacteria are the only pathogens routinely tested for in food samples, whereas viruses and parasites are typically tested in stool specimens of persons infected after food consumption. The food processor tests for specific types of bacteria and can choose among culture tests, gene probes, manual immunoassays, and instruments (automated immunoassays) (Kroll, 2001). 

For patients who develop diarrhea after 3 days of hospitalization, 15% to 20% of cases are due to C. difficile.This suggests that in hospitalized patients, especially in those who are exposed to antimicrobial therapy or chemotherapy, the stool specimen should be tested for C. difficile toxin(s). In immunocompromised hosts, a wide range of viral, bacterial, and parasitic agents should be tested. 

Although less commonly associated with severe GI disease, pes-tivirus, torovirus, and coronavirus-like particles have been recovered from diarrheal stools. In HIV-infected patients, the presence of diarrhea is associated with virus in 35% of stool specimens. Astrovirus, picobirnavirus, calicivirus, and adenovirus appear to be the most commonly isolated viral pathogens. Table 111-5 presents specific characteristics of these agents. 

T. Schlaurman, R. de Boer, R. Patty, M. Kooistra-Smid, and A. van Zwet Comparative evalnation of in-honse manual, and commercial semi-automated and automated DNA extraction platforms in the sample preparation of human stool specimens for a Salmonella enterica 5 -nuclease assay. Journal of Microbiological Methods 71, 238-245 (2007)... 

The isopropyl and ethoxycarbonylmethyl derivatives of 3-(5-nitro-2-furyl) acrylamide proved to be effective in the treatment of Schistosoma japonicum °. After one to two weeks of therapy with a total dosage of 700 to 1,500 mg of one of the drugs, 50 per cent of all treated patients had negative stool specimens. The rate of worm elimination in animals (drug doses were not stated) was extremely high in mice 100 per cent, in rabbits 97 to 100 per cent, and in dogs 85 to 90 per cent . 

Stool specimens or iierineal swabs are negative for parasite. 

Data have been obtained concerning the stability of ampicillin in human stool specimens. Sixty-four to eighty-four percent of the ampicillin was recovered after 3-4 week storage of the stool-buffer blend in dry ice. A recovery cont control consisting of the sample stool-buffer blend dosed with a known amount of ampicillin was prepared for each sample. When a correction is made based on the recovered penicillin from the control, full recovery of ampicillin and stability through 3 weeks is obtained from the stool-buffer mixture . When ampicillin was incubated with the fecal flora of rats and tested for antibiotic activity, only 36.7% of the ampicillin activity was left after 4 hours . ... 

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