|EVALUATION OF SPUTUM SMEARS PREPARED BY DIFFERENT
|N Naganathan, KT Ganapathy & R Rajalakshmi: Indian
J Med Res 1979, 69, 893-900.
Sputum microscopy is the main casefinding tool
in tuberculosis control programmes. The technique of smear preparation
is an important step which needs to be simple for wide applicability.
It is often stressed that smear should be prepared from the purulent
portions of the sputum as they are likely to have more number of
bacilli. It may not be possible for the microscopist/paramedical
worker at the periphery to strictly follow this procedure. Hence,
a study was conducted to compare the sensitivity of 4 methods of
sputum smear preparation viz., direct smear prepared (i) blindly
without making any selection of portions of sputum specimen, (ii)
from portions of sputum material likely to contain the bacilli,
(iii) after mixing up the sputum specimens thoroughly, and (iv)
from centrifuged deposit after homogenization of sputum with sodium
hydroxide and concentration by centrifugation. Culture was also
done for Mycobacterium tuberculosis.
A total of 549 specimens were employed. Positivity
rates by four methods were: 79.6% by method (i), 80.3% by method
(ii), 80.7% by method (iii) and 77.2% by method (iv). There was
no statistically significant difference in the number of positives
obtained from different methods. Centrifuged deposit smears proved
to be in no way better than the direct smears. The differences
in the methods lay only in the classification of positive smear
as of a low or high grade.
|KEY WORDS: SMEAR EXAMINATION, SENSITIVITY METHODS,
|RECOVERY OF TUBERCLE BACILLI FROM URINE OF PULMONARY
TUBERCULOSIS PATIENTS AND ITS COMPARISON WITH THE CORRESPONDING SPUTUM
|VK Challu, B Mahadev, R Rajalakshmi & K Chaudhuri:
Indian J TB 1989, 36, 107-11.
A study was done to compare (1) the filtration
method with conventional centrifugation method for the recovery
of tubercle bacilli from urine and (2) drug sensitivity profile,
virulence for guinea pigs and phage type of the urine isolates with
the corresponding isolates from the sputum of cases of bacillary
Urine specimens from 236 pulmonary tuberculosis
patients were cultured by routine centrifugation method as well
as filtration method. Filtration was done by passing urine through
a 0.45 um membrane filter and treating the membrane with 5% oxalic
acid for 15 minutes. LJ medium was used for culture in both the
methods. Centrifugation yielded 27 positives (11.6%) whereas
filtration gave 12 (12.6%) out of 95 specimens filtered. Contamination
was more with filtration method. Comparison of the biological
properties of M.tuberculosis isolated from urine and sputum of the
same patients revealed difference in drug sensitivity profile or
virulence for guineapigs for 13 of 25 (52%) of the pairs of isolates
tested. Moreover 4 of 11 pairs subjected to phage typing were found
to differ in both major and minor phage types. The significance
of these findings in the light of the pathogenesis of tuberculosis
is also discussed.
|KEY WORDS: FILTRATION, CENTRIFUGATION, SENSITIVITY,
VIRULENCE, SPECIFICITY, TUBERCLE BACILLI.