An ancestral genomic locus in Mycobacterium tuberculosis clinical isolates from India hints the genetic link with Mycobacterium canettii.

BACKGROUND: Tuberculosis remains a worldwide public health emergency. To better understand M. tuberculosis and to identify genomic variations characteristic to the Indian clinical isolates by a low-cost method, a genomic subtractive hybridization between M. tuberculosis H37Rv and a clinical isolate from South India was performed. RESULTS: This revealed a novel 0.4-kb subtractive fragment which was used as a handle to pull out a 4.5-kb genomic region characteristic to the clinical isolate and was absent in H37Rv. On further studies, this 4.5-kb region was found to be present in 91% of the M. tuberculosis clinical isolates screened from Kerala, a state in South India. Interestingly, this novel region has 99% identity (with 100% query coverage) with genomic regions of M. canettii. DISCUSSION: The present study hypothesizes that this locus was present in the recent common environmental ancestor of mycobacteria, retained to the maximum extent in M. canettii and ancestral isolates of M. tuberculosis, and later deleted in other modern lineages of M. tuberculosis. Thus, this region may serve as one of the links between the pathogenic mycobacteria and the environmental species. We also propose that the Indian isolates of M. tuberculosis might be closely related to the putative progenitor M. prototuberculosis with respect to this locus. More studies on other genomic loci from different strains of M. tuberculosis are required to establish more links in this direction.

Lite-YOLOv8: a more lightweight algorithm for Tubercle Bacilli detection.

Deep learning is a transformative force in the medical field and it has made significant progress as a pivotal alternative to conventional manual testing methods. Detection of Tubercle Bacilli in sputum samples is faced with the problems of complex backgrounds, tiny and numerous objects, and human observation over a long time not only causes eye fatigue, but also greatly increases the error rate of subjective judgement. To solve these problems, we optimize YOLOv8s model and propose a new detection algorithm, Lite-YOLOv8. Firstly, the Lite-C2f module is used to ensure accuracy by significantly reducing the number of parameters. Secondly, a lightweight down-sampling module is introduced to reduce the common feature information loss. Finally, the NWD loss is utilized to mitigate the impact of small object positional bias on the IoU. On the public Tubercle Bacilli datasets, the mean average precision of 86.3% was achieved, with an improvement of 2.2%, 1.5%, and 2.8% over the baseline model (YOLOv8s) in terms of mAP0.5, precision, and recall, respectively. In addition, the parameters reduced from 11.2 to 5.1 M, and the number of GFLOPs from 28.8 to 13.8. Our model is not only more lightweight, but also more accurate, thus it can be easily deployed on computing-poor medical devices to provide greater convenience to doctors.

Research on detection method of Tubercle Bacilli based on the improved YOLOv5.

In the field of medical imaging, the detection method of Tubercle Bacilli based on deep learning can overcome the shortcomings of traditional manual detection methods, such as large subjectivity, large workload, slow detection speed, and reduce the occurrence of false detection or missed detection under specific circumstances. However, due to the small target and complex background of Tubercle Bacilli, the detection results are still not accurate enough. In order to reduce the influence of sputum sample background on Tubercle Bacilli detection and improve the accuracy of the model for Tubercle Bacilli detection, a target detection algorithm YOLOv5-CTS based on YOLOv5 algorithm is proposed in this paper. The algorithm first integrates the CTR3 module at the bottom of Backbone of YOLOv5 network to obtain more high-quality feature information, which brings significant performance improvement to the model; then in the neck and head part, a hybrid model with the improved feature pyramid networks and the added large-scale detection layer is utilized to perform feature fusion and small target detection; finally, the SCYLLA-Intersection over Union loss function is integrated. The experimental results show that YOLOv5-CTS increases the mean average precision to 86.2% compared with the existing target detection algorithms for Tubercle Bacilli, such as Faster R-CNN, SSD and RetinaNet, etc, which shows the effectiveness of this method.

Effects of smoking on the severity and transmission of pulmonary tuberculosis: A hospital-based case control study.

Introduction: There is a high incidence of both smoking and tuberculosis (TB) in China. This study examined the risk factors for severe pulmonary TB (PTB) and positive tubercle bacilli in sputum. Methods: We conducted a retrospective case-control study in a tertiary hospital from January 2017 to December 2018 (n = 917). The clinical and biological characteristics of patients were collected, and univariable and multivariable logistic regression analyses were performed to assess the factors associated with smoking in terms of the severity and transmission of PTB. Results: Positive tubercle bacilli in sputum and severe PTB were much higher in smoking patients. Together with nutrition status, heavy smoking exhibited a 284% greater risk in severe PTB. Positive tubercle bacilli in sputum was significantly associated with hypoproteinemia and smoking regardless of the status, duration, and degree. Conclusion: Because cigarette smoking was strongly and inversely associated with hypoproteinemia, we conclude that smoking plays a critical role in the severity and transmission of PTB. Smoking cessation interventions should be employed to prevent severe PTB and decrease the transmission of PTB.

The performance of tongue swabs for detection of pulmonary tuberculosis.

Introduction: Oral and/or tongue swabs have demonstrated ability to detect Mycobacterium tuberculosis (Mtb) in adults with pulmonary tuberculosis (TB). Swabs provide useful alternative specimens for diagnosis of TB using molecular assays however, the diagnostic pickup by culture requires further improvement and development. Several studies identified the presence of differentially culturable tubercle bacilli (DCTB) populations in a variety of clinical specimens. These organisms do not grow in routine laboratory media and require growth factors in the form of culture filtrate (CF) from logarithmic phase cultures of Mtb H37Rv. Methods: Herein, we compared the diagnostic performance of sputum and tongue swabs using Mycobacterial Growth Indicator Tube (MGIT) assays, Auramine smear, GeneXpert and DCTB assays supplemented with or without CF. Results: From 89 eligible participants, 83 (93%), 66 (74%) and 79 (89%) were sputum positive by MGIT, smear and GeneXpert, respectively. The corresponding tongue swabs displayed a lower sensitivity with 39 (44%), 2 (2.0%) and 18 (20%) participants respectively for the same tests. We aimed to improve the diagnostic yield by utilizing DCTB assays. Sputum samples were associated with a higher positivity rate for CF-augmented DCTB at 82/89 (92%) relative to tongue swabs at 36/89 (40%). Similarly, sputum samples had a higher positivity rate for DCTB populations that were CF-independent at 64/89 (72%) relative to tongue swabs at 26/89 (29%). DCTB positivity increased significantly, relative to MGIT culture, for tongue swabs taken from HIV-positive participants. We next tested whether the use of an alternative smear stain, DMN-Trehalose, would improve diagnostic yield but noted no substantial increase. Discussion: Collectively, our data show that while tongue swabs yield lower bacterial numbers for diagnostic testing, the use of growth supplementation may improve detection of TB particularly in HIV-positive people but this requires further interrogation in larger studies.

Tubercular mycotic aortic aneurysm: A case report.

Tubercular aneurysms of larger vessels, particularly the aorta is very rare. The first case of tubercular involvement of the aorta in the form of aortitis was reported in 1882 by Weigert and the first case of tubercular mycotic aneurysm of the aorta was reported in 1895. The preoperative diagnosis of tubercular aortic aneurysm is difficult. Even at surgery, determining the tubercular nature of the lesion is problematic. The gross appearance may not be distinctive, and acid-fast stains are unlikely to be performed. We report the case of a young female patient who was started on antitubercular treatment for pleural effusion and was found to have aortic aneurysm, which later on proved to be tubercular in origin.

Smooth Tubercle Bacilli: Neglected Opportunistic Tropical Pathogens.

Smooth tubercle bacilli (STB) including "Mycobacterium canettii" are members of the Mycobacterium tuberculosis complex (MTBC), which cause non-contagious tuberculosis in human. This group comprises <100 isolates characterized by smooth colonies and cordless organisms. Most STB isolates have been obtained from patients exposed to the Republic of Djibouti but seven isolates, including the three seminal ones obtained by Georges Canetti between 1968 and 1970, were recovered from patients in France, Madagascar, Sub-Sahara East Africa, and French Polynesia. STB form a genetically heterogeneous group of MTBC organisms with large 4.48 ± 0.05 Mb genomes, which may link Mycobacterium kansasii to MTBC organisms. Lack of inter-human transmission suggested a yet unknown environmental reservoir. Clinical data indicate a respiratory tract route of contamination and the digestive tract as an alternative route of contamination. Further epidemiological and clinical studies are warranted to elucidate areas of uncertainty regarding these unusual mycobacteria and the tuberculosis they cause.

Studies on Cultivation and Drug-Resistance of Tubercle Bacilli Isolated from Renal Tuberculosis / 대한비뇨기과학회지

Author performed clinical studies at random on 19 patients with renal tuberculosis who were admitted for the period of April 1958 through February 1959 to Department of Urology at Seoul National University Hospital as to tuberculosis bacterial cultures and their resistance tests using pre- and postnephrectomy urine and diseased tissue itself. The results in this study were summarized as follows: 1. All except one case had received antituberculosis medication for not more than 6 months. 2. To all cases beginning at the time of admission preoperation medications consisting of SM 1.0 gm, PAS 12gm, and INH 300mg, and these regimen were given throughout study. 3. The culture positivity rates were 79% in prenephrectomy bladder urine. 90% in caseous material from diseased renal cavity and 44% in postnephrectomy bladder urine. The lower were the culture positivity rate in prenephrectomy bladder urine, the longer the preceding period of antituberculosis drugs given. Culture positivity rate of caseous material from diseased renal cavity, however, was persistently high irrespective of the length of the antituberculosis medication and the culture positivity rate of postnephrectomy bladder urine appeared to be dependent more on the presence or absence of the remaining renal tuberculosis rather than on the period of antituberculosis medication. 5. From the repeated culture of prenephrectomy bladder urine over short period of time, in the same individual results were rather inconstant and this seemed to be independent upon the use of antituberculosis drugs. 6. Cultural studies on urine and diseased renal tissue yielded the same results whether it was checked on the day of specimen collection or after less than 7 day's refrigerated storage. 7. While doing cultural studies from prenephrectomy bladder urine on patients who received antituberculosis drugs one case was found to need more than two months to grow and this trend seemed to be more so in cases of cultures from diseased renal tissues. 8. Resistance was shown as to SM in 9 cases out of 10 cases on whom prenephrectomy bladder urines were checked, in 5 out of 6 cases on whom tuberculosis culturers were done from diseased renal caseous tissues and in 2 cases out of each group possessed resistance to PAS as well. 9. Resistance to SM was to be easily acquired and afterward the degree of resistance seemed to increase rapidly from the use of SM of short duration. 10. Cases with positive microscopic finding and negative cultures were seen only in prenephrectomy bladder urine and this fact was thought not to be specifically related to the antituberculosis treatment. 11. Cases with negative microscopic finding and positive cultures were seen in patient who received only long antituberculosis treatment and these were characterized by small number of colonies. 12. The appearance of resistant strain was found not to be specifically related with the status of microscopical finding on prenephrectomy bladder urine nor with cultural studies on the same specimen.

A Clinical Study of Tubercle Bacilli in Urine of the Patients with Pulmonary Tuberculosis / 대한비뇨기과학회지

One hundred and twenty-six patients with pulmonary tuberculosis having no clinical evidence of genito-urinary tuberculosis were studied for tubercle bacilli in their urine and the following results were obtained 0f 126 patients studied, 5 cases (4.0%) were found having positive tubercle bacilli in urine. of which three were found in the moderately advanced cases of pulmonary tuberculosis and two in the far-advanced. While, in the treated group of 56 with anti-tuberculous drugs for pulmonary tuberculosis, three cases were positive for tubercle bacilli in urine, of which two were found in the moderately advanced and one in the far-advanced of pulmonary tuberculosis, two cases were also positive in the non-treated group of 70, of which one was found in the moderately advanced and another in the far-advanced of pulmonary tuberculosis. Two instances of positive tubercle bacilli in urine were found in the group of treatment for less than 6 months and only one in patients having treatment for more than 6 months.

A Clinical Study of I.V.P. and Tubercle Bacilli in Urine of the Patients with Pulmonary Tuberculosis / 대한비뇨기과학회지

Sixty-nine pulmonary tuberculosis patients with no clinical evidence of genito-urinary tuberculosis were studied of I.V.P. and tubercle bacilli in their urine and the following results were obtained: Of 69 patients studied, 3 cases (4.34%) were found having positive tubercle bacilli in their urine of which two were found in the thirty-two moderately advanced cases and one was found in twenty-one far-advanced of their pulmonary tuberculosis. One of three was treated irregularly with anti-tuberculous triple therapy during about seven months and two were not treated Of 69 patients studied, 3 cases (4.34%) were found having positive intravenous pyelographic examination, of which two cases were group 1 of Lattimer's classification and one was group 3. Two of these were found in moderately advanced pulmonary tuberculosis and one was far-advanced.

A Clinical Study on Examination of Tubercle Bacilli in Renal Tuberculosis / 대한비뇨기과학회지

Comparative studies were performed between discovery of tubercle bacilli from prenephrectomy bladder urine and other clinical tests as performed on all 19 patients with renal tuberculosis who had been admitted to the Department of Urology at Seoul National University Hospital for the period of April 1958 hrough February 1959. The results in this study were summarized as follows: 1. Modes of antituberculosis medications prior to admission on these patients were as follow: SM only, 4 cases; combined use of SM and PAS, a cases; SM, PAS and INHcombined, 1 cases; unknown, 4 cases, and not used in 3 cases. 2. Durations of antituberculosis medications were as follow: Less one month, 4 cases, less than 6 months, 7 cases; over 6 months, 1 case; unknown, 4 cases, and not used in 3 cases. 3. Positivity rate for microscopic examination was 79% on prenephrectomy bladder urine and when two cases who also developed prostatic tuberculosis were excluded the positivity rate was 76% 4. Discovery of tubercle bacilli was not easy even on urine specimen which showed much protein and many white blood cells. 5. Cases which did not reveal tubercle bacilli on microscopic examination from caseous material of tuberculous renal cavity again showed microscopical negativity from prenephrectomy bladder urine. 6. The presence of the severe lesion of bladder wall was not related with ease with which tubercle bacilli being found from prenephrectomy bladder uriue. 7. Adverse effect was to be foundfrom antituberculosis medication as to the tubercle bacilli on prenephrectomy urine. Cases who had used antituberculosis drugs for less than one month showed high positivity rate equal to the cases who never did. 8. It was deemed unnecessary to stop using antituberculosis medication of less than two months' duration in order to discover tubercle bacilli on prenephrectomy bladder urine. 9.Inability to discover tubercle bacilli on prenephrectomy bladder urine was not wholly due to the previous use of antituberculosis drugs and to raise the positivity rate repeated examination would be indicated.