• Korean Journal of Veterinary Service
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• v.46 no.1
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• pp.29-34
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• 2023

Mycobacterium tuberculosis complex (M. tuberculosis complex) is a causative agent of contagious chronic disease in a wide range of mammalian hosts, mainly cattle, goat, pigs, wildlife, and humans. The definite diagnosis of tuberculosis is made based on culture of M. tuberculosis, but it takes a long time. In the present study, we analyzed whether the detection time of M. tuberculosis could be reduced when cultured in the medium containing the culture-promoting ingredients-107 (CPI-107) using the BacT/Alert 3D system, an automatic culture system. The time to detection (TTD) tended to decrease as the added concentration of CPI-107 increase. In the case of low numbers of M. tuberculosis, it decreased by 21.0% at 1.2 mg/mL of CPI-107 and by 15.9% in the case of high numbers of M. tuberculosis. In the culture using clinically isolated M. tuberculosis strains, the shortening of the culture time by CPI was more evident. In conclusion, the detection time of M. tuberculosis was shortened in the medium added with CPI-107, and this could be used for isolation, culture and drug susceptibility test of M. tuberculosis.

• Korean Journal of Veterinary Service
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• v.41 no.4
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• pp.239-244
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• 2018

Mycobacterium tuberculosis (M. tuberculosis) complex is the causative agent of tuberculosis (TB) in humans and bovine TB in mammalian hosts and grows very slowly. Selenium is a central molecule in nitrogen metabolism and an essential ingredient for all living cells and glutamic acid. The effects of selenium on the growth of M. tuberculosis, a representative slow-growing Mycobacterium species, were investigated and measured using the BacT Alert 3D System (MB/BacT System). Sodium selenate, at a final concentration of $10{\mu}g/mL$, reduced the average time-to detection (TTD) to 197.2 hours (95% confidence interval (CI), 179.6~214.8) from 225.1 hours (95% CI, 218~232.0) in the control culture media (P<0.05). The TTD did not increase with $\text\tiny{L}$-glutamate concentrations up to $10{\mu}g/mL$, but a significant reduction in the TTD was observed in the presence of $20{\mu}g/mL$ ${\text\tiny{L}}$-glutamate in culture media (P<0.05). In conclusion, selenate and ${\text\tiny{L}}$-glutamate enhance the growth of M. tuberculosis.

• Tuberculosis and Respiratory Diseases
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• v.81 no.3
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• pp.233-240
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• 2018

Background: Non-conversion of sputum smear and culture prolongs the infectivity of the patient and has been associated with unfavorable outcomes. We aimed to evaluate factors associated with persistent sputum positivity at the end of two months of treatment of new case pulmonary tuberculosis (TB). Methods: Data of 87 human immunodeficiency virus-negative patients with culture-positive drug-susceptible pulmonary TB admitted to local university hospital between September 2015 and September 2016 were reviewed. Factors associated with sputum smear and/or culture positivity at the end of the second month of treatment were analyzed. Results: Twenty-two patients (25.3%) remained smear and/or culture-positive. Male sex, lower body mass index (BMI), unemployment, alcohol abuse, higher number of lobes involved and cavities on chest X-rays, shorter time to detection (TTD) on liquid cultures, higher respiratory sample smear grading and colony count in solid cultures, higher C-reactive protein, erythrocyte sedimentation rate, leukocytosis, thrombocytosis, and anemia were all significantly associated with persistent sputum positivity. However, in the logistic regression analysis only male sex, lower BMI, alcohol abuse, higher radiological involvement, cavitation, higher smear grading, higher colony count in solid cultures and shorter TTD were determined as independent factors associated with persistent sputum positivity at the end of 2 months of treatment. Conclusion: In conclusion, higher sputum smear and culture grading at diagnosis, shorter TTD, higher number of lobes involved, cavitation, male sex, alcohol abuse, and lower BMI were independently associated with persistent sputum positivity. These factors should be sought when distinguishing which patients will remain infectious longer and possibly have worse outcomes.