Surgery and Healing in the Developing World - Dartmouth-Hitchcock

Lab in a Suitcase
Table 1. Selected common pathogenic bacteria
Gram + ve cocci Gram + ve bacilli (rods)
Staphylococci Bacillus anthracis
Staph aureus Listeria monocytogenes
Staph epidermidis Clostridium tetani
Streptococci Clostridium difficile
Strep pyrogens
Strep pneumoniae
E. faecalis
Gram - ve cocci Gram - ve bacilli (rods)
Neisseria meningitidis Escherichia coli
Neisseria gonorrhoeae Salmonella
Shigella
Yersinia pestis
Bordetella pertussis
Pseudomonas aeruginosa
Mycobacterium tuberculosis
Mycobacterium leprae
The Carbol Fushion Stain
Mycobacterium tuberculosis (TB) is very prevalent in developing countries, therefore
rapid identification is necessary. TB is stained using carbol fucsin staining and is
known for its resistance to decolarization. If TB is suspected obtain sputum or CSF
from the patient and make a smear on a glass slide. When making the smear remember
not to make it too thick as this will distort the view.
Carbol Fucsin Procedure
1. Make smear of sample
2. Heat fix by passing through flame 3 times
3. Cover smear with carbol fucsin using an eyedropper, (1-2 min)
4. Heat fix smear by passing through flame 3 times
5. Wash with running water until water runs clear
6. Cover smear with 20% H2SO4, (2-4 min)
7. Wash with running water. Note: if still colored then repeat acid
decolarization step
8. Wash with running water
9. Cover smear with methylene blue, (2-4 min)
10.Wash with running water until water runs clear
11.Heat dry and observe under oil immersion
Microscopic Observation of Carbol Fucsin Stain
Examine the slide in a manner similar to that described for the Gram stain in the
previous section. TB is a Gram negative (red) bacilli (rod).
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