Characterization of mycobacterium tuberculosis and predisposing factors associated with tuberculosis among risk population in Baghdad city

Abstract EN

Background : Tuberculosis (TB) remains one of most common infectious diseases wide distribution in the world.

The predisposing factors and unimmune responsiveness (immune anergy) increase the severity of this disease.

The technological advances have large improvement in diagnosis of early stages of this disease.

Aim of study : To evaluate the commonly laboratory methods used for the diagnosis of TB.

To assess the state of some aspects of immune response in TB patients ; and to investigate some risk factors associated with tuberculosis.

Methods : This study was applied on 70 TB patients who were admitted to Specialized Chest and Respiratory Center in Baghdad Medical City, Iraq.

It involved also 30 apparently healthy as control group.

Sputum and sera samples were collected from both groups according to the standard methods.

Bacterial isolates of Mycobacterium tuberculosis were identified by staining technique, colonial morphology, biochemical reactions, and by molecular detection (Gene Xpert).

Each patient check for some risk factors such as : Age, gender, diabetic status, and viral infection with cytomegalovirus (CMV).

Estimation of certain immune criteria in TB patients as interferon-gamma (IFN–γ), interleukin-2 (IL-2) and CMV antibodies (CMV-Abs) by standard methods.

Results : The diagnosis of TB using Gene Xpert method was highly specificity 100 %, sensitivity 92.9 % and accuracy 95 %.

There was an increase in TB cases among age groups 41-50 and followed by 21-30 years old of TB patients.

The study showed that there is no significant difference (p > 0.05) in the level of sera IFN-γ and IL-2 between TB patients and control group, while there was a significant (p < 0.001) increase in the level of anti-CMV IgG among study groups.

Also there is a significant (p < 0.05) decrease in the levels of IL-2 and IFN-γ between diabetic TB patients compared with those non-diabetic TB patients.

In addition, there is significant decrease (p > 0.05) in the mean serum concentration of IL-2 and IFN-γ between tobacco smoking TB patients compared with non-smokers TB patients.

Conclusion : This study provides evidence that the Gene Xpert assay is the best diagnostic method used for TB detection.

The cytokine of TB patients reflects an immunological anergy induced by some predisposing factors as diabetes mellitus, tobacco smoking and viral infection that lead to reduction of immunity level in TB patients.