Identification and Isolation of Mycobacterium tuberculosis from Iranian Patients with Recurrent TB using Different Staining Methods

Re-activation of tuberculosis (TB) and the emergence of multi-drug resistance (MDR) isolates is a serious problem in the worldwide. Thus, accelerating the recognition of resistance of Mycobacterium tuberculosis isolated from TB patients is important. The aim of this study was to identifying and isolation of M. tuberculosis isolates from Iranian patients with recurrent TB using different staining methods. During 16 months from October 2013 to February 2015, 176 sputum samples were collected from patients suspected with TB who were under treatment or had the infection with TB resistant to treatment referred to the Health Centre in Sari and Ghaemshahr. The sputum specimen’s smears provided with four specific staining techniques. Data analysis was performed using t-test and descriptive statistics frequency distribution by SPSS–version 16 software. And Pvalues <0.05 was considered statistically significant. Of total 176 tuberculosis patients, 28 cases (15.9%) were AFB smear-positive sputum and also 17 cases (9.65%), 11 (6.25%) were male and female, respectively. The mean age of patients was 47±2 years. The sensitivity of Ziehl–Neelsen stain and Fluor chrome staining respectively was 82% and 100%, while specificity of Zihle-Neelson, Fluorochrome respectively were 86% and 100%. Direct examination of sputum samples of patients under treatment and treatment-resistant with mycology staining methods revealed that the fungi were observed in 3 patients (7.1%). Our results showed that the sensitivity of Ziehl–Neelsen stain was lower than Fluorochrome staining, while specificity of Zihle –Neelson was higher than Fluorochrome so, use of both staining methods is needed.