daphne 2 - patient kwan siew lan

Patient : Kwan Siew Lan
Complaints : diarrhea
Diagnosis : Enterocolitis

Collection and Transportation of specimens
5 g or 5 ml of fresh faecal specimen is collected into a screw-cap container using a small wooden or plastic spoon. For solid specimens, a single spoonful is satisfactory. Liquid specimens should not fill the container to more than one third to avoid spillage when the container is opened.

The specimen of choice is faeces. If faeces are not readily obtainable, a rectal swab may be submitted. The swab is passed beyond the anal sphincter, carefully rotated and withdrawn. It is then placed in a screw-cap tube.

Those portions of the faeces which contain pus, blood or mucous should be submitted for culture.

Equipments and Materials

Materials
Blood plate agar (BAP)
Salmonella-Shigella Agar modified (SS)
Campylobacter Selective medium
MacConkey Agar (MAC)
Thiosulphate-citrate bile sucrose agar (TCBS)
Selenite broth
Alkaline peptone water (APW)
Cefsulodin-Irgasan-Novobiocin (CIN) agar for Yersinia enterocolitica
Sorbitol MAC for enterohaemorrhagic E.coli
Loeffler’s methylene blue
Enterococcosel Agar with 6 microgram / ml of vancomycin

Equipment
Biological safety cabinet

Procedure

Microscopy
A wet preparation is examined for the presence of leucocytes and erythrocytes. Their presence may indicate invasive disease. This test is only done on request as its usefulness is limited.

Place a drop of liquid faeces or saline suspension of the faecal specimen on a microscope slide. Any mucous or flecks of pus or blood that may be present should be included in the suspension as these are likely to harbour disease causing organisms
Mix 1 drop of Loeffler’s methylene blue stain with the faeces specimen. Note that there must be an equal volume of faeces to stain.
Place a cover slip over it.
Wait 2 – 3 minutes for the nuclei to stain and then read the preparation under high power on (40x)
Observe for predominating numbers of white blood cells (WBCs), which indicate an invasive pathogen.

Culture
Inoculated places are O2 incubated unless otherwise indicated in the table.

All faeces are inoculated onto the following media: BAP, MAC, SS, Selenite broth and Campylobacter selective agar for the isolation of salmonella, Shigella and Campylobacter spp.

In addition to the above:
Bloody faeces are also inoculated onto Sorbitol MAC plate.
Watery faeces are plated on TCBS and inoculated onto APW to culture for Vibrio spp.