Examination for growth after overnight incubation.
Y. pestis is a highly infectious organism.
Maximum care should be taken
Lownstein Jensen (LJ) Meduim if Buruli ulcer is suspected:
Decontaminate the swab by immersing it in sodium hydroxide 40g/l (4% W/v) solution for 10 minutes.
Inoculate the decontaminated specimen on two slopes of acid LJ medium.
Incubate one slope at 35-370C as described for culture of M. tuberculosis and incubate the other slope at 320C for up to 8 weeks.
9 Microscopical examination Routine: Gram Smear: Look for: Gram positive cocci that could be S. aureus Gram positive streptococci that could be S. pyogenes or other streptococci. Gram negative rods that could be p. aeroginosa, proteus speices, E.coli or other coliforms. 9 If tropical ulcer is suspected, look for vincent’s organisms If cutaneus anthrax is suspected, look for large Gram variable rods lying in chains that could be B. anthracis.