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Background: The emergence of drug-resistant tuberculosis (DR-TB) has been a major obstacle to global tuberculosis control programs, especially in developing countries, including Ethiopia. This study investigated drug resistance patterns and associated mutations of Mycobacterium tuberculosis Complex (MTBC) isolates from the Amhara, Gambella, and Benishangul-Gumuz regions of Ethiopia. Methods: A cross-sectional study was conducted using 128 MTBC isolates obtained from patients with presumptive tuberculosis (TB). Phenotypic (BACTEC MGIT 960) and genotypic (MTBDRplus and MTBDRsl assays) methods were used for drug susceptibility testing. Data were entered into Epi-info and analyzed using SPSS version 25. Frequencies and proportions were determined to describe drug resistance levels and associated mutations. Results: Of the 127 isolates recovered, 100 (78.7%) were susceptible to four first-line anti-TB drugs. Any drug resistance, polydrug resistance, and multi-drug resistance (MDR) were detected in 21.3% (27), 15.7% (20), and 15% (19) of the isolates, respectively, by phenotypic and/or genotypic methods. Mono-resistance was observed for Isoniazid (INH) (2, 1.6%) and Streptomycin (STR) (2, 1.6%). There were two genotypically discordant RIF-resistant cases and one INH-resistant case. One case of pre-extensively drug-resistant TB (pre-XDR-TB) and one case of extensively drug-resistant TB (XDR-TB) were identified. The most frequent gene mutations associated with INH and rifampicin (RIF) resistance were observed in the katG MUT1 (S315T1) (20, 76.9%) and rpoB (S531L) (10, 52.6%) genes, respectively. Two MDR-TB isolates were resistant to second-line drugs; one had a mutation in the gyrA MUT1 gene, and the other had missing gyrA WT1, gyrA WT3, and rrs WT1 genes without any mutation. Conclusions: The detection of a significant proportion of DR-TB cases in this study suggests that DR-TB is a major public health problem in Ethiopia. Thus, we recommend the early detection and treatment of DR-TB and universal full first-line drug-susceptibility testing in routine system. [ABSTRACT FROM AUTHOR]

In 2016, the World Health Organization (WHO) estimated that there were 147,000 cases and 12,500 deaths worldwide from tuberculosis, which is predominantly caused by Mycobacterium bovis. However, because of the [...]

Background: There is limited information on the performance of the Xpert® MTB/RIF test for diagnosis of smear-negative pulmonary tuberculosis (SNPT) and rifampicin resistance (RR) in the same-day diagnosis approach. The effects of sputum quality and other factors affecting the Xpert performance are also under-investigated. Objective: This study aimed to determine the performance of the Xpert® MTB/RIF test for detection of SNPT and RR in the same-day diagnosis strategy and the effect of sputum quality and other factors on its performance. Methods: A cross-sectional study was conducted from August 2017 to January 2018 across 16 health facilities in Addis Ababa, Ethiopia. Two spot sputum samples were collected from 418 presumptive SNPT patients, tested with Xpert® MTB/RIF, then compared to tuberculosis culture. Additionally, culture isolates were tested for RR by BACTEC MGIT™ 960 drug susceptibility testing (DST) and MTBDRplus version 2. Results: The Xpert® MTB/RIF test detected 24 (5.7%) SNPT cases, with a sensitivity of 92.3% (75.9% – 97.9%) and specificity of 99.2% (97.8% – 99.7%) compared with tuberculosis culture. Xpert® MTB/RIF also detected three (11.58%) RR strains with 100.0% concordance with BACTEC MGIT™ 960 DST and MTBDRplus results. Three blood-stained SNPT samples were positive by Xpert (30.0%), which was 6.9 times higher compared to salivary sputum (odds ratio: 6.9, 95% confidence interval: 1.36–34.96, p = 0.020). Conclusion: The performance of the Xpert® MTB/RIF to detect SNPT and RR in same-day diagnosis is high. However, SNPT positivity varies among sputum qualities, and good sample collection is necessary for better test performance. [ABSTRACT FROM AUTHOR]

BACKGROUND: Mycobacterial infections are known to cause a public health problem globally. The burden of pulmonary disease from nontuberculous mycobacteria is reportedly on the rise in different parts of the world despite the fact that there is limited data about the disease in sub-Saharan Africa including Ethiopia. Hence, we aimed to assess the magnitude of M. tuberculosis and nontuberculous mycobacteria (NTM) among presumptive pulmonary tuberculosis patients attending St. Paul's hospital Medical College, Addis Ababa, Ethiopia. METHODS: A cross-sectional study was conducted from June to September 20/2016. Morning sputum specimens were collected, processed and cultured in Lowenstein Jensen medium and BACTEC MGIT 960 media. The nontuberculous mycobacteria were further confirmed and characterized by Genotype CM/AS assays. The socio-demographic, clinical and chest x-ray data were collected using a structured questionnaire. The data was analyzed using SPSS version 20. RESULTS: Out of 275 presumptive tuberculosis patients enrolled in the study, 29(10.5%) were culture positive for Mycobacteria. Of these, 3(10.3%) were found to be NTM and 26(89.6%) were Mycobacterium tuberculosis complex. Of the NTM, two were unidentified and one typed as M.peregrinum. There was no coisolation of Mycobacterium tuberculosis complex and nontuberculous mycobacteria. Overall, 6(23.1%) Mycobacterium tuberculosis complex isolates were resistant to at least one antituberculosis drug. Of these, two were multidrug resistant tuberculosis cases (7.7%) detected from previously treated patients. CONCLUSION: Relatively low magnitude of Mycobacterium tuberculosis complex and nontuberculous mycobacteria isolates were seen in the study area. Therefore, further study using a large sample size is needed to be done to consider nontuberculous mycobacteria infection as a differential diagnosis in presumptive pulmonary tuberculosis patients. [ABSTRACT FROM AUTHOR]

Background: There is limited information on the performance of the Xpert ® MTB/RIF test for diagnosis of smear-negative pulmonary tuberculosis (SNPT) and rifampicin resistance (RR) in the same-day diagnosis approach. The effects of sputum quality and other factors affecting the Xpert performance are also under-investigated., Objective: This study aimed to determine the performance of the Xpert ® MTB/RIF test for detection of SNPT and RR in the same-day diagnosis strategy and the effect of sputum quality and other factors on its performance., Methods: A cross-sectional study was conducted from August 2017 to January 2018 across 16 health facilities in Addis Ababa, Ethiopia. Two spot sputum samples were collected from 418 presumptive SNPT patients, tested with Xpert® MTB/RIF, then compared to tuberculosis culture. Additionally, culture isolates were tested for RR by BACTEC MGIT™ 960 drug susceptibility testing (DST) and MTBDRplus version 2., Results: The Xpert ® MTB/RIF test detected 24 (5.7%) SNPT cases, with a sensitivity of 92.3% (75.9% - 97.9%) and specificity of 99.2% (97.8% - 99.7%) compared with tuberculosis culture. Xpert ® MTB/RIF also detected three (11.58%) RR strains with 100.0% concordance with BACTEC MGIT™ 960 DST and MTBDRplus results. Three blood-stained SNPT samples were positive by Xpert (30.0%), which was 6.9 times higher compared to salivary sputum (odds ratio: 6.9, 95% confidence interval: 1.36-34.96, p = 0.020)., Conclusion: The performance of the Xpert ® MTB/RIF to detect SNPT and RR in same-day diagnosis is high. However, SNPT positivity varies among sputum qualities, and good sample collection is necessary for better test performance., Competing Interests: The authors declare that they have no financial or personal relationships that may have inappropriately influenced them in writing this article., (© 2022. The Authors.)

Background: Digestion and decontamination of non-sterile clinical specimens such as sputum are an essential step in the isolation of mycobacteria. Masking of mycobacteria in Mycobacterial growth indicator tube (MGIT) 960 liquid culture system by fungi and bacteria other than mycobacteria is a major problem., Objective: To assess the effect of 1.5% sodium hydroxide final concentration on recovery rate of mycobacterial species and decontamination of other bacterial and fungal contaminants from sputum sample., Methodology: Laboratory based cross sectional study with convenient sampling technique was carried out on subjects referred to the National Tuberculosis Reference Laboratory of Ethiopian Public Health Institute from November 2015 to February 2016. Single morning sputum was collected from each patient and analyzed., Results: A total of 264 subjects were enrolled in the study. The mean age of participant was 31 (SD 20.14 - 41.42) years old. The majority (61%) were male. Increasing the final concentration of NaOH from 1% to 1.5% reduced the contamination rate from 22.4% to 6.8% (P<0.001) without affecting mycobacterial recovery (P=1.00). A total of 26 different species of microbial contaminants were identified as being associated with BACTEC MGIT 960 culture system., Conclusion: Results presented in this study demonstrated that the use of a final concentration of 1.5% NaOH with NALC method aids in reducing culture contamination rate for decontaminating sputum samples referred for tuberculosis culture diagnosis. Among the identified microbial contaminants, the most predominant was coagulase negative Staphylococcus species.