Cerehrospinal fluid examination
Cerehrospinal fluid: when the sampes is brought into the clinics it is necessary that the clinicians should be notified instantaneously for the organism that is suspected to be present in the sample. The sample is generally sent in sterile universal container. Direct smear staining is the most preferable method used for the specimen examination, at the same time culture should be set instantaneously as the as the sample get into the laboratory. For every spinal fluid, is sterile but sometimes do improper handling of the sample, contaminant may be introduce into the sample, this may either take place from the ward where the sample is collected or during laboratory analysis procedure.
First thing to observed when cerebrospinal fluid is sent to laboratory, is to check either the fluid is clear or cloudy, after that transfer the sample into a sterile centrifuge container, but make sure that the quantity is left as a reserve.
Centrifuge the fluid at 2000rpm for 5 minutes. Discard the supernatant fluid into a sterile container keep it until it is needed for biochemical analysis or other investigation. From the sediment, make two slide film, used one film for gram staining and the second film for acid fast bacilli or organism.
Use the deposit to prepared for culture using blood agar and medium. When blood agar is prepared and inoculated, prepare another, but these should be chocolate media now and then inoculate. The culture should be incubated anaerobically at 35ºC and 10%CO2 . next day, examine your culture for any growth, any growth colonies found should be identify and sensitivity test carried out on the growth colonies.
Incase of suspicious tuberculous meningitis, lowenstain-jenson slope prepared and inoculated and incubate it at 37ºC for a maximum period of 8 weeks. But regular interval check is necessary when tuberculosis meningitis is suspected. The cerebrospinal fluid can be inoculated overnight at a temperature of 35ºC via the above explain procedures.
Above all when any of the following organism listed bello is observed;
They could be the course of the infection or as a contaminant. But note that the above listed organism are associated with the course or meningitis. So when one of the the organism isolated from the culture, further investigation should be carried out.
In case of tuberculosis meningitis, on the macroscopical examination, a spider slot is often noted on the fluid, when such is observed, decant the fluid slowly into clean watch glass, lay a clean piece of lens paper on the clot gently, by doing that the clot will stick to the paper. Then blot the cloth onto a clean glass slide fixed and used ziehl- Neelsen staining method to stain the sample.
Stool: these are usually collected with a suitable container with a wide mouth and cover, or are collected with a rectal swab and to the laboratory but incase of preserving the life span of the same organism such as enteric pathogen, then it is recommended to used cary lair transport medium. Some of these implicated enteric pathogens are salmonella, shigellae, vibrio, Yersinia, complobacter, Escherichia coli, Aeromonas, and verotoxigenic. These organism also involved do to out break of food poison, such organism are staphylococcus aureus, clostridium perfringens and bacillus cereus. These organism can all be isolated by special selective method. The stool may also be screen for mycobacterium tuberculosis or other parasite.