الفهرس 
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Abstract
This study aims at comparison between traditional methods in TB
diagnosis and a serodiagnostic method based on detection of lgG
antibodies directed against specific Mycobacterium tuberculosis antigens
(38 kDa antigen &16 kDa antigen) using a commercially available
ELISA kit to evaluate its sensitivity and specificity.
The study was carried out on 60 patients attending the outpatient
clinic of Benha chest hospital and inpatient Zagazig Chest hospital.
Thirty control subjects were included and compromised of 15 patients
who were admitted to the chest department in Benha university hospital
and 15 healthy blood donors who came for blood donation at the Blood
Bank of Benha University Hospital. Laboratory tests were carried out at
Microbiology & Immunology Department of Benha Faculty of Medicine.
The study was done from March (2011) to August (2012).
The patients were selected according to the clinical , radiological
and laboratory data suspecting open pulmonary tuberculous infection.
Those with past history of TB, on antituberculous treatment, HIV positive
and new cases not willing for informed consent were excluded.
All patients under study were subjected to:
Full history taking
Clinical examination.
Radiological examination.
The control subjects included (15) patients who were admitted
to Benha University Hospital with pulmonary diseases other than TB in
addition to (15) healthy voluntary blood donors who came for blood
donation at the Blood Bank of Benha University Hospital.
SUMMARY
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Early morning sputum sample and blood samples were collected
from shared patients and the control group and subjected to the following:
A. SPUTUM SAMPLES:
I- Decontamination and Concentration.
II- Staining: Ziehl Neelsen stained smears
III- Culture:
1. Löwenstein-Jensen (LJ) medium: The isolated bacterial colonies
were identified by:
Ziehl Neelsen stain.
Nitrate reduction test.
Niacin production test.
2. Manual Mycobacteria Growth Indicator Tube (MGIT).
B. BLOOD SAMPLES:
They were used to detect lgG antibodies directed against
specific mycobacterium tuberculosis antigens (38 kDa antigen &16-kDa
antigen) using commercially available ELISA kit (PATHOZYME TB
COMPLEX PLUS, Omega Diagnostics)
The results of the study showed the following:
1. Out of the 60 patients with pulmonary tuberculosis; 40 (66.7 %) were
males and 20 (33.3%) were females with male to female ratio 2:1.
2. The most frequent age group affected by pulmonary tuberculosis was
the 25-34 age group (30%), followed by 15-24 age group (26.6%) then
35-44 and 45-54 age groups (16.6% each)
3. As regards the occupation of patients under study, 42 (70%) of the
cases with pulmonary tuberculosis were manual workers, 12 cases
(20%) were house wives and 6 cases (10%) were employers.
4. There is significant association between TB infection and cigarette
smoking.
SUMMARY
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5. 28.3% of the studied TB cases have a positive family history of TB
infection compared to 2% in the control group.
6. 56.7% of the studied TB cases were diabetics compared to 26.7% in
the control group and this is statistically significant
7. The mean detection times of mycobacterium tuberculosis from the
sputum samples on MGIT was 11.9 ± 3.2 days compared to 28.3 ± 6.3
days when using LJ medium.
8. The sensitivity and specificity of BBL MGIT were 90% and 86.7%
respectively.
9. 45% of the studied TB patients were seropositive for 38-kDa and 16-
kDa antigens.
10. The sensitivity and specificity of the Pathozyme TB complex plus
(ELISA test) were 45% and 93.3% respectively.
11. Although MGIT is more costly and laborious, it has distinct
advantages over the conventional LJ culture with respect to faster
growth. It is safe, and simple to use and does not require exogenous
gas or radioactive elements compared with other mycobacterial
cultures. Nevertheless, due to LJ culture positive but BBL MGIT
negative specimens, a combination of solid and liquid culture systems
is still required for the highest recovery of mycobacteria from clinical
specimens.
12. The ELISA test (Pathozyme TB complex plus) is simple, easy to
perform but to replace culture, the ‘gold standard’ recommended by the
WHO, the sensitivity and specificity of a satisfactory serological test
should be higher than 80% and 95% respectively. So this test has a
good specificity and a lower level of sensitivity than recommended.
13. But this sensitivity is comparable to the compromised sensitivity of
the direct microscopic examination of clinical samples by Ziehl-
Neelsen staining technique (the most commonly used method for rapid
diagnosis in limited resources labs). So, this test may be useful in
diagnosis, although its use alone is not recommended as a single tool to
confirm or to rule out TB.
14. So it could be used in combination with other methods to increase
diagnostic accuracy, especially for culture-negative tuberculosis cases
and extrapulmonary TB which are difficult to diagnose.
RECOMMENDATION
)115(
RECOMMENDATIONS
1- Strict precautions should be followed by those in contact with
tuberculous cases to prevent disease transmission.
2- Smoking should be prohibited due to the significant association
between smoking and tuberculosis.
3- All tuberculous patients should be tested for diabetes mellitus due to
the significant association between diabetes and tuberculosis.
4- Although MGIT is more costly and laborious, it has distinct
advantages over the conventional LJ culture with respect to faster
growth. It is safe, and simple to use and does not require exogenous
gas or radioactive elements compared with other mycobacterial
cultures. Nevertheless, due to LJ culture positive but BBL MGIT
negative specimens, a combination of solid and liquid culture systems
is still required for the highest recovery of mycobacteria from clinical
specimens.
5- The ELISA test (Pathozyme TB complex plus) is simple, easy to
perform, has a very good specificity and an acceptable sensitivity. To
replace culture, the ‘gold standard’ recommended by the WHO, the
sensitivity and specificity of a satisfactory serological test should be
higher than 80% and 95% respectively. So this test has a good
specificity and a lower level of sensitivity than recommended. But this
sensitivity is comparable to the compromised sensitivity of the direct
microscopic examination of clinical samples by Ziehl-Neelsen
staining technique (the most commonly used method for rapid
diagnosis in limited resources labs). So, this test is useful in diagnosis,
RECOMMENDATION
)116(
although its use alone is not recommended as a single tool to confirm
or to rule out TB. It could be used in combination with other methods
to increase diagnostic accuracy, especially for culture-negative
tuberculosis cases and extrapulmonary TB which are difficult to
diagnose.
6- Further studies are required to assess this test especially in diagnosing
cases with closed pulmonary and extrapulmonary TB, the groups that
can get the utmost benefit of it.