For an infectious disease like tuberculosis, which
is transmitted by aerosol droplets, the rapid and
accurate detection of M.tuberculosis is essential,
not only to speed up the treatment of the patient
but also to control the spread of the disease.
Tuberculosis in childhood occurs with different
manifestations. All these forms of tuberculosis,
except when cavitation occurs in pulmonary
tuberculosis, are paucibacillary in nature. For
this reason, even though at the present time
bacteriological confirmation is still the final
proof of tuberculous disease, it is difficult to
obtain.
Depending on the form of disease manifestation,
several specimens like sputum and/or gastric
lavage, as children are often unable to produce
sputum, lymph nodes and other biopsy specimens,
pus, ascitic fluid, pleural or cerebrospinal
fluid (CSF) need to be collected. If delay is
anticipated, relevant specimens may be collected
in suitable transport medium for sending it to the
laboratory.
There are two ways to address diagnosis of
tuberculosis. The direct approach is concerned
with the detection of the bacteria by microscopy
or culture, detection of tuberculostearic acid (bacterial
wall component), detection and identification
of mycobacterial antigen by the use of
polyclonal or monoclonal antibodies, analysis of
lipid composition by chromatography, and the
detection of DNA or RNA of mycobacterial
origin by hybridization with a DNA probe with
or without amplification of nucleic acids. The
indirect approach relates to measurement of host
immune response against the mycobacteria. This
includes humoral immunity via the detection of
antibodies against the bacteria and cellular response
via skin tests
