The WHO continues to search for innovative technologies to enhance accurate and reliable laboratory diagnosis of TB to curb Mycobacterium tuberculosis and DR-TB worldwide. However, the emergence of drug-resistant forms of TB, which need more resources to detect, treat, and effectively reduce the burden of disease is a challenging problem. GeneXpert™ MTB/RIF assay is a new automated real-time Nucleic Acid Amplification Technology that overcomes many of the current operational difficulties in TB diagnosis .
TB affects mostly adults in the economically productive age groups with approximately two-thirds of cases estimated to occur among people aged 15-59 years .
In the present study, the overall forms of presumptive Mycobacterium tuberculosis positivity rate were 24.3%. Our finding was similar to studies conducted in the Debre Markos Hospital (23.2%) , Gondar Referral Hospital (24.6%) , Gambella (20.0%) , Afar (24.5%) , India (27.6%) , South Africa (26%) , Nigeria (22.9 %)  And the WHO report in Africa (25%) . However, it was lower compared to reports in Jigjiga (65.5%) , Kenya (32.25%) , in eastern Uttar Pradesh (32.9%)  and Congo (79.1%) .The main difference in these latter findings may show our inclusion of all forms of presumptive tuberculosis while other studies included identified cases of Mycobacterium tuberculosis. In contrast, our finding was higher when compared with studies conducted in Metema and Armacho (5.7%) , Felege Hiwot Referral Hospital, and Debre Tabor Hospital (14.6%) , in three referral hospitals and the regional laboratory in Addis Ababa (15.11%) , other parts of Ethiopia (4.7%-10.8%) [21-23], Nigeria (10.3%)  and India (2.31%) .The variations might be due to the difference in study design, type and number of participants, and environmental conditions.
The co-infection of TB-HIV in this study was found to be high at 33.3% (171/513). This finding was supported by previous studies conducted in Amhara (27.7%) , Gambella , in Ethiopia (29.4%) , and in Central Nigeria (36.3%) . However, our findings were higher than studies conducted in the Debre Markos Referral Hospital (16.6%) , different studies across Ethiopia (20.3-24.2 %) [14,29-32], and a WHO estimation for Ethiopia of 14% (9.6%-19%) . Conversely, the findings were lower than studies conducted in the Felege Hiwot Referral Hospital and Debre Tabor Hospital (41.9%) , Zambia (98.3%) , and South Africa (>70%) . The possible explanations for this difference could be reflect policy recommendations for which HIV infected patients, as an eligible group, are more likely to be tested using GeneXpert™.
In this study, Mycobacterium tuberculosis was prevalent in all ages, but have seriously hit the age group of 30-44 years with 26.0% and of whom 34/420 (8.1%) were rifampicin resistant. The positivity finding was in line with studies conducted in Gondar (29.8%) , different studies in Ethiopia [21-23,35], WHO reports 2017  and Agaro Teaching Health Center in southwestern Ethiopia .However, contrary findings with several studies in a different part of Nigeria and Zambia [18,24,33] which had lower prevalence, but higher than a study conducted in eastern Uttar Pradesh (40%) .
In the present study, the percentage of Mycobacterium tuberculosis positivity significantly higher in presumptive TB patients (20.0 %) compared to presumptive drug resistance (4.3 %) with (P < 0.00). This finding was comparable to studies conducted in Afar (20.9) , Debre Markos Referral Hospital (15.1%)  and Gambella (19.6%) . However, it is much lower than studies conducted in Felege Hiwot Referral Hospital and Debre Tabor Hospital (54.8) , Gondar (25.2 %)  and Zimbabwe (37.1%) .The discrepancies might be due to our inclusion of all presumptive TB cases, and a high number of participants.
According to our study, we found 132 (9.1%) of rifampicin-resistant cases among confirmed TB cases. This result is comparable with studies conducted in Debre Markos Referral Hospital (10.3%) , Felege Hiwot Referral Hospital and Debre Tabor Hospital (9.3%) , Addis Ababa (9.9 %)  and India (10.5%) .Our finds are higher than studies conducted on northwest, east and south parts of Ethiopia (2.9%-5.7%) [6,19,31-32,39,42,46 and 48], Nigeria (2.9%)  and Zambia (5.9%) .The possible explanation for these variations could be related to our retrospective approach spanning four years, or differences in study designs .However, our incidence was lower than for studies conducted in Gondar 15.8% ,other parts of Ethiopia (11.5-39.4) [39-40and 51],Congo (42.2%)  and China (17.6-26.3%) [43 and 50].
Limitation of the Study
As we collected retrospective data from the GeneXpertTM TB registration book, we encountered data missing and incompleteness. Variables included for associated factors were also limited.