Hi! This is Shameema. I was posted to Central Processing Area (CPA) in the Department of Diagnostic Bacteriology for the first 3 weeks. I worked on the respiratory, blood and stoot. On the forth week i was moved to parasite.
As Muna and Jennifer have done the posting about respiratory and urine, I will share my experience on stool in this blog.
Stool Culture
The stool culture test is used for the detection and identification of pathogenic bacteria in the stool. In the laboratory, the test is initiated by streaking small amount of a fresh fecal sample to a variety of media; details as follows:
The stool incubated in the selenite broth and alkaline peptone is cultured on to agar plates the following day:
Selenite --> MacConkey and SS agar plate
Alkaline peptone --> TCBS and blood plate
It is crucial that the subculture for alkaline peptone has to be done the following day. This is because the pH of the alkaline peptone which is set at pH 8 will decrease in the presences of vibro as acid is the end product of vibro. Decrease in the acidity increases the growth of other organism and decrease the concentration of vibro thus affecting the result. Selenite broth is the selective broth that will rule out the normal flora.Vancomycin Resistance Enterococci Screening (VRE)
Enterococci are bacteria found in stool and some strains of the enterococci has become resistance to vancomycin antibiotic is referred to as VRE.
On the stool table I also had to do the widal weil- felix test. It is a diagnostic used for typhoid fever. It is an illness caused by the bacterium Salmonella enterica serovar typhi. The precense is detected by the aggultination of somatic (O) and flagellar (H) to Salmonella typhi in the patient's serum. Weil-Felix test is the detection of rickettsial antibodies thus indicating the presence of rickettsial species in the patient.
PROCEDURE
1. Blood sample is centrifuged at 2000rpm for 5 minutes to separate the serum from the blood.
2. Add 0.2ml of the patient serum to 7.8ml of normal saline in test tube to form 1/40 dilution.
3. Add 1ml of 1/40 dilution serum to 1 ml of normal saline to form 1/80 dilution.
4. Arrange Dryer’s tubes as demonstrated in table below and add one drop of commercial antigen in the Dryer’s tubes.
5. Add 0.8ml of the 1/40 dilution test serum to Dryer tube number 1-6 and 1/80 dilution serum to Dryer tube 7 and 8..
6. Shake the racks gently to remove trapped air.
7. Incubate overnight at 50 degree Celcius in water bath.
TO: Solmonella typhi Group D somatic antigen
TH: Salmonella typhi-H flagellar antigen d
AH: Salmonella parathyphi: A-H flagellar antigen a
BH: Salmonella parathypi B-H group B somatic antigen
OX19: Proteus OX19 antigen
OXK: Proteus OXK antigen
Will share my parasite experiance in my next blog.
Shameema :)
hello shameema~!
ReplyDeleteI'm also learning the weil-felix test too. But my department do rapid card screening before doing the tube method. Does your department do the card method too? Or they just straightaway do the tube method? And also, does the trapped air bubbles affect the reading? Because for my side, they say bubbles are okay.
CYA ON FRI~!
yaNLing xD
Hi! No, our lab does not do the card method, we straightaway just do the tube method.Well, the bubbles does not really affects the result but we are advised to gently tap the tubes to release any bubbles present... The volume and the pipetting technique is more important...
ReplyDeleteDo you grow the stool in multiple agar? Say, both MacConkey agar and Salmonella Shigella? For confirmation purposes.
ReplyDeleteFor example, you suspect is camphylobacter species. Do you grow on both camphylobacter agar and Salmonella Shigella agar?
So that you can confirm your test that it is camphylobacter species if colony are only found on camphylobacter agar and not Salmonella Shigella agar.
Or is there a very distinct difference that you are about to distinguish between each of them? For example, salmonella turns a different colour from shingella.
Note: Typo error at the first paragraph.
I worked on the respiratory, blood and stoot.
Stoot? or Stool?
Who in TG01-group 2 posted the comment on 27 July?
ReplyDeleteYes, we grow stool in multiple agar. This is to identify the confirm the bacteria growth. The identification of the bactieria pressent is done in the identification lab.
ReplyDeleteShameema
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