The global tuberculosis situation. Progress and problems in the 20th century, prospects for the 21st century

Dual-Energy Computed Tomography Lung in patients of Pulmonary Tuberculosis

Objectives

The objective of this study was to characterize findings of high-resolution computed tomography (HRCT) and dual-energy CT (DECT) (80 keV, 140 keV, and mixed) in pulmonary tuberculosis (TB) patients and to compare and correlate HRCT and DECT findings.

Material and Methods

This cross-sectional study was conducted on 67 patients of 18-65 years of age who were suspected cases of pulmonary TB with signs and symptoms of cough, fever, hemoptysis, sputum, night sweats, and weight loss with positive sputum AFB examinations/bronchoalveolar lavage. All the patients subjected to HRCT scan and followed with DECT scan. Comparison of various imaging techniques (DECT 80 keV, DECT 140 keV, and DECT mixed) with HRCT was done for detecting lung findings and data so obtained were subjected to statistical analysis.

Results

On comparing the various imaging techniques with HRCT for detecting consolidation, tree in bud pattern, cavitary lesions, ground-glass opacity, bronchiectasis, atelectasis, nodules, granuloma, peribronchial thickening, and fibrosis, the maximum agreement of HRCT was found with DECT 80 keV and minimum agreement was found with DECT 140 keV.

Conclusion

The study concluded that DECT 80 keV monochromatic reconstructions among 80 keV, mixed, and 140 keV monochromatic reconstructions in lung parenchyma window settings are a faster and better analytical tool for the assessment of findings of pulmonary TB when compared with HRCT.

Clinical and radiological features of pulmonary tuberculosis in patients with idiopathic pulmonary fibrosis

BACKGROUND

Data regarding the radiological and clinical features of pulmonary tuberculosis (PTB) in patients with idiopathic pulmonary fibrosis (IPF) are limited. Accordingly, the aim of this study was to investigate the clinico-radiological features of PTB in patients with IPF.

METHODS

Clinico-radiological variables were retrospectively compared between PTB patients with and without IPF (TB-IPF and TB-control, respectively), and computed tomography (CT) findings were compared between the TB-IPF group and patients with nontuberculous mycobacterial lung disease and IPF (NTM-IPF).

RESULTS

Of 609 IPF patients, 28 (4.6%) were diagnosed with PTB. In the TB-IPF group, incidental radiological finding was the most common presenting manifestation, and the rate of treatment success was significantly lower than in the TB-control group. On CT scan, the typical locations of reactivated PTB were significantly less often involved in the TB-IPF group than in the TB-control group. The TB-IPF group exhibited a significantly lower frequency of centrilobular nodules and a higher rate of consolidation-predominant pattern than did the TB-control group. CT findings in the TB-IPF group were similar to those in the NTM-IPF group.

CONCLUSIONS

Incidental radiological findings were the most common presenting manifestations in TB-IPF patients, who were more likely to present with atypical PTB manifestations on CT scan and who experienced poorer treatment outcomes.

Click chemistry based regioselective one-pot synthesis of coumarin-3-yl-methyl-1,2,3-triazolyl-1,2,4-triazol-3(4H)-ones as newer potent antitubercular agents

Coumarin-3-yl-methyl-1,2,3-triazolyl-1,2,4-triazol-3(4H)-ones (8k-z) were synthesized via copper(I)-catalyzed azide-alkyne cycloaddition click chemistry. The synthesized hybrid molecules were characterized by spectral studies. Compounds 8k-z were screened for their in vitro anti-TB activity by using the Microplate Alamar Blue assay and for cytotoxicity using the MTT assay. Some of the compounds were found to be most potent against the tested Mycobacterium tuberculosis H37Rv strain with a MIC of 1.60 µg/ml. Further, docking the compounds into the InhA binding pocket showed strong binding interactions and effective overall docking scores were recorded. The drug-likeness and toxicity studies were computed using Molinspiration and Protox, respectively.

A prospective study on quality of life in patients with pulmonary tuberculosis at a tertiary care hospital in Kashmir, Northern India

BACKGROUND

Pulmonary Tuberculosis (PTB) is a contagious, airborne infection that destroys when M. tuberculosis primarily attacks the lungs. PTB is curable with an early diagnosis and antibiotic treatment. Stigmatization and negative emotions resulting from the illness could result in long term impairment of patients psychological well being which may result in work absenteeism resulting in loss of productivity and reduced monthly income.

METHODS

This was a prospective study which was conducted over a period of one and half year. A total of 198 patients were recruited for the study. Quality Of Life (QOL) was assessed at baseline and at the end of intensive phase. For QOL WHO based QOLBREF was used.

RESULTS

In the present study patients scored lowest in the baseline physical (8.36 ± 1.60) followed by the psychological domain (10.40 ± 1.72) however at the end of intensive phase both physical (11.98 ± 1.70) and psychological (12.75 ± 1.) domains improved very much and the difference was statistically significant.

CONCLUSION

We conclude that HRQOL is significantly reduced in patients with PTB, and that it improves rapidly and significantly with DOTS-based intensive phase of treatment. Special focus on reduction of stigmatization should be given in the management of TB to reduce the psychological distress.

Second-line anti-tuberculosis drug resistance testing in Ghana identifies the first extensively drug-resistant tuberculosis case

BACKGROUND

Drug resistance surveillance is crucial for tuberculosis (TB) control. Therefore, our goal was to determine the prevalence of second-line anti-TB drug resistance among diverse primary drug-resistant Mycobacterium tuberculosis complex (MTBC) isolates in Ghana.

MATERIALS AND METHODS

One hundred and seventeen MTBC isolates with varying first-line drug resistance were analyzed. Additional resistance to second-line anti-TB drugs (streptomycin [STR], amikacin [AMK] and moxifloxacin [MOX]) was profiled using the Etest and GenoType MTBDRsl version 2.0. Genes associated with resistance to AMK and MOX (gyrA, gyrB, eis, rrs, tap, whiB7 and tlyA) were then analyzed for mutation.

RESULTS

Thirty-seven (31.9%) isolates had minimum inhibitory concentration (MIC) values ≥2 µg/mL against STR while 12 (10.3%) isolates had MIC values ≥1 µg/mL for AMK. Only one multidrug-resistant (MDR) isolate (Isolate ID: TB/Nm 919) had an MIC value of ≥0.125 µg/mL for MOX (MIC = 3 µg/mL). This isolate also had the highest MIC value for AMK (MIC = 16 µg/mL) and was confirmed as resistant to AMK and MOX by the line probe assay GenoType MTBDRsl version 2.0. Mutations associated with the resistance were: gyrA (G88C) and rrs (A514C and A1401G).

CONCLUSION

Our findings suggest the need to include routine second-line anti-TB drug susceptibility testing of MDR/rifampicin-resistant isolates in our diagnostic algorithm.

18F-Fluoro-2-Deoxy-d-Glucose PET/Computed Tomography Evaluation of Lung Cancer in Populations with High Prevalence of Tuberculosis and Other Granulomatous Disease

Pulmonary tuberculosis infects one-third of world's population and is responsible for the high mortality and morbidity in developing countries. The presence of a high number of macrophages and lymphocytes in active tuberculosis granulomas is associated with high uptake of ¹⁸F-fluoro-2-deoxy-d-glucose on PET imaging mimicking lung cancer. In many cases, radiological features of pulmonary tuberculosis are undistinguishable from lung cancer, which makes the diagnosis difficult. Clinical history and computed tomographic (CT) findings on a hybrid PET/CT are as important as findings on a PET in the diagnosis of lung cancer.

Design, synthesis, and in vitro antituberculosis activity of benzo[6,7]cyclohepta[1,2-b]pyridine-1,3,4-oxadiazole derivatives

A new antitubercular agents, benzo[6,7]cyclohepta[1,2-b]pyridine-1,3,4- oxadiazole hybrids (6a-o), have been designed and synthesized involving oxidative cyclization of hydrazones by use of di(acetoxy)iodobenzene, characterized by IR,¹ H NMR,¹³ C NMR, and HRMS, and further confirmed by X-ray analysis. All the newly synthesized compounds 4a-o evaluated for their in vitro antimycobacterial activity against Mycobacterium tuberculosis H37Rv (ATCC27294). Among the compounds tested, the compounds 4o (MIC: 1.56 μg/ml) and 4l, 4m (MIC: 3.125 μg/ml) are promising lead analogues and have shown lower cytotoxicity.

A Novel and Efficient Five-Component Synthesis of Pyrazole Based Pyrido[2,3-d]pyrimidine-diones in Water: A Triply Green Synthesis

A novel one pot synthesis of pyrazolo[4′,3′:5,6]pyrido[2,3-d]pyrimidine-diones, via a five-component reaction, involving, hydrazine hydrate, ethyl acetoacetate, and 1,3-dimethyl barbituric acid, an appropriate aryl aldehydes and ammonium acetate catalyzed via both of heterogeneous and homogeneous catalysis in water, is reported.

A Structure-Activity Relationship Study of Naphthoquinone Derivatives as Antitubercular Agents Using Molecular Modeling Techniques

Tuberculosis (TB) is one of the major causes of death worldwide. Mycobacterium tuberculosis, the leading causative agent of TB, is responsible for the morbidity and mortality of a large population worldwide. In view of above and as a part of our effort to develop new and potent anti-TB agents, a series of substituted naphthoquinone derivatives were subjected to molecular modeling using various feature selection methods. The statistically significant best 2D-QSAR model having correlation coefficient [Formula: see text] and cross-validated squared correlation coefficient [Formula: see text] with external predictive ability of [Formula: see text] was developed by SA-PLS, and group-based QSAR model having [Formula: see text] and [Formula: see text] with [Formula: see text] was developed by SA-PLS. Further analysis using three-dimensional QSAR technique identifies a suitable model obtained by SA-partial least square method leading to antitubercular activity prediction. k-nearest neighbor molecular field analysis was used to construct the best 3D-QSAR model using SA-PLS method, showing good correlative and predictive capabilities in terms of [Formula: see text] and [Formula: see text]. The pharmacophore analysis results obtained from this study show that the distance between the aromatic/hydrophobic and the naphthoquinone moiety sites to the aliphatic and acceptor groups should be connected with almost the same distance for significant antitubercular activity. The information rendered by QSAR models may lead to a better understanding of structural requirements of antitubercular activity and also can help in the design of novel potent antitubercular activity.

Anything to Stay Alive: The Challenges of a Campaign for an Experimental Drug

Drug-resistant tuberculosis (TB) has a high mortality rate. Most medicines used to treat it are poorly tested and have terrible side effects. Activists have campaigned for patients with drug-resistant TB to have access to experimental drugs, particularly one called bedaquiline, before these have been approved by regulatory authorities such as the Food and Drug Administration (FDA) in the United States (US) and the Medicines Control Council (MCC) in South Africa. Some activists have also campaigned for bedaquiline to be approved by regulatory authorities before testing of the drug is completed. These campaigns raise ethical concerns about whether patients should be offered experimental, unapproved, medicines for the treatment of life-threatening illnesses, and if authorities should approve drugs for life-threatening illnesses when vital questions about safety and efficacy remain outstanding.

Intuitive weights of harm for therapeutic decision making in smear-negative pulmonary Tuberculosis: an interview study of physicians in India, Pakistan and Bangladesh

Background

To estimate the amount of regret and weights of harm by omission and commission during therapeutic decisions for smear-negative pulmonary Tuberculosis.

Methods

An interviewer-administered survey was done among young physicians in India, Pakistan and Bangladesh with a previously used questionnaire. The physicians were asked to estimate probabilities of morbidity and mortality related with disease and treatment and intuitive weights of omission and commission for treatment of suspected pulmonary Tuberculosis. A comparison with weights based on literature data was made.

Results

A total of 242 physicians completed the interview. Their mean age was 28 years, 158 (65.3%) were males. Median probability (%) of mortality and morbidity of disease was estimated at 65% (inter quartile range [IQR] 50-75) and 20% (IQR 8-30) respectively. Median probability of morbidity and mortality in case of occurrence of side effects was 15% (IQR 10-30) and 8% (IQR 5-20) respectively. Probability of absolute treatment mortality was 0.7% which was nearly eight times higher than 0.09% reported in the literature data. The omission vs. commission harm ratios based on intuitive weights, weights calculated with literature data, weights calculated with intuitive estimates of determinants adjusted without and with regret were 3.0 (1.4-5.0), 16 (11-26), 33 (11-98) and 48 (11-132) respectively. Thresholds based on pure regret and hybrid model (clinicians’ intuitive estimates and regret) were 25 (16.7-41.7), and 2(0.75-7.5) respectively but utility-based thresholds for clinicians’ estimates and literature data were 2.9 (1-8.3) and 5.9 (3.7-7.7) respectively.

Conclusion

Intuitive weight of harm related to false-negatives was estimated higher than that to false-positives. The mortality related to treatment was eightfold overestimated. Adjusting expected utility thresholds for subjective regret had little effect.

Efficacy and safety of recombinant Mycobacterium tuberculosis ESAT-6 protein for diagnosis of pulmonary tuberculosis: a phase II trial

BACKGROUND

This study aimed to determine the efficacy and safety of recombinant Mycobacterium tuberculosis ESAT-6 protein for diagnosis of pulmonary tuberculosis (TB).

MATERIAL AND METHODS

A phase II trial was performed in 158 patients with pulmonary TB (145 initially-treated and 13 re-treated) and 133 healthy subjects. Skin testing was carried out by injecting purified protein derivative (PPD) (on left forearm) or recombinant ESAT-6 protein at a dosage of 2, 5, or 10 μg/mL (on the right forearm) in each subject. Reaction activity and adverse events were monitored at 24, 48, and 72 h following the injection. Receiver operating characteristic curves were plotted to determine the areas under the curves (AUCs) and the cut-off induration diameters for the optimal diagnostic performance.

RESULTS

The reaction activity was significantly increased upon recombinant ESAT-6 injection in pulmonary TB patients compared with healthy subjects. In pulmonary TB patients, the reaction was dose-dependent, and at 48 h, 10 μg/mL recombinant ESAT-6 produced a reaction similar to that produced by PPD. The AUCs for a 10 μg/mL dosage were 0.9823, 0.9552, and 0.9266 for 24 h, 48 h, and 72 h, respectively, and the induration diameters of 4.5-5.5 mm were the optimal trade-off values between true positive rates and false positive rates. No serious adverse events occurred in any subjects.

CONCLUSIONS

Recombinant ESAT-6 protein is efficacious and safe for diagnosing pulmonary TB. Based on the reaction, performance, safety, and practicability, we recommend that 10 μg/mL at 48 h with an induration cut-off value of 5.0 mm be used.

Differentiation between tuberculosis and lymphoma in mediastinal lymph nodes: Evaluation with contrast-enhanced MDCT

AIM

To determine the specific imaging criteria on contrast-enhanced multidetector computed tomography (MDCT) for differentiating between tuberculosis and lymphoma in mediastinal lymph nodes.

MATERIALS AND METHODS

The anatomical distribution and enhancement patterns of mediastinal lymph nodes on contrast-enhanced MDCT were reviewed in 37 patients with tuberculosis and 54 patients with lymphoma. Of the patients with lymphoma, 18 had Hodgkin's disease and 36 had non-Hodgkin's lymphoma.

RESULTS

Region 10R was involved more often in tuberculosis than in Hodgkin's disease and non-Hodgkin's lymphoma. Region 6 had a higher tendency to be affected in Hodgkin's disease and non-Hodgkin's lymphoma compared with tuberculosis. Tuberculosis showed peripheral enhancement in 78% of cases, frequently with a multilocular appearance, compared to Hodgkin's disease and non-Hodgkin's lymphoma, which showed peripheral enhancement in only 6 and 3% of cases, respectively. Homogeneous enhancement was more commonly seen in lymphoma (83% for Hodgkin's disease, and 83% for non-Hodgkin's lymphoma) than in tuberculosis (8%). In the determination of tuberculosis, results showed that when a peripheral enhancement pattern was seen, sensitivity was 78%, specificity was 96%, and accuracy was 89%. In the determination of lymphoma, results showed that when a homogeneous enhancement pattern was seen, sensitivity was 83%, specificity was 92%, and accuracy was 87%.

CONCLUSION

The findings of the present study indicate that specific anatomical distribution and enhancement patterns of lymphadenopathy shown on contrast-enhanced MDCT can be useful in differentiating tuberculosis from lymphoma of mediastinal lymph nodes.

Tuberculous otitis media with endobronchial tuberculosis

Although tuberculosis can affect various organs and tissues, the lung is the site most commonly involved. Extrapulmonary tuberculosis (EPTB) involves relatively inaccessible and variable sites and is consequently often overlooked by clinicians. The ear is a notably very rare site of EPTB, and the diagnosis is difficult because of the variable and confusing signs and symptoms. To our knowledge, this is the first case in which tuberculous otitis media and endobronchial tuberculosis coexisted.

Design, synthesis of some new (2-aminothiazol-4-yl)methylester derivatives as possible antimicrobial and antitubercular agents

A series of (2-aminothiazol-4-yl)methylester (5a-t) derivatives were synthesized in good yields and characterized by (1)H NMR, (13)C NMR, mass spectral and elemental analyses. The crystal structure of 5a was evidenced by X-ray diffraction study. The compounds were evaluated for their preliminary in vitro antibacterial, antifungal activity and were screened for antitubercular activity against Mycobacterium tuberculosis H37Rv strain. The synthesized compounds displayed interesting antimicrobial activity.

Nitrate reduction pathways in mycobacteria and their implications during latency

Mycobacterial persistence has gained a lot of attention with respect to developing novel antitubercular drugs, which could drastically reduce the duration of tuberculosis (TB) therapy. A better understanding of the physiology of Mycobacterium tuberculosis, and of the metabolic state of the bacillus during the latent period, is a primary need in finding drug targets against persistent TB. Recent biochemical and genetic studies of nitrate reduction in mycobacteria have revealed the roles of distinct proteins and enzymes involved in the pathway. The differential degree of nitrate reduction among pathogenic and non-pathogenic mycobacterial species, and its regulation during oxygen and nutrient limitation, suggest a link between nitrate reduction pathways and latency. The respiratory and assimilatory reduction of nitrate in mycobacteria may be interconnected to facilitate rapid adaptation to changing oxygen and/or nitrogen conditions, increasing metabolic flexibility for survival in the hostile host environment. This review summarizes the nitrate metabolic pathways operative in mycobacteria to provide an insight into the mechanisms that M. tuberculosis has evolved to adapt successfully to the host environment.

Developing pyrrole-derived antimycobacterial agents: a rational lead optimization approach

Tuberculosis (TB) represents a never-ending challenge toward which research efforts are needed. Drug resistance is the key problem that scientists in the field need to fight. The development of new drugs endowed with novel modes of action against different biological targets is of extreme importance; these new agents should also exhibit lower toxicity compared with the anti-TB drugs currently available. Furthermore, new drugs should be inexpensive since most of the TB-infected population lives in developing nations. In the last few years, numerous researchers have focused their attention on TB, leading to the discovery of some interesting compounds. Among these, the pyrrole-derived compounds we developed can be considered very promising antimycobacterial agents. Aided by molecular modeling studies, we synthesized numerous compounds characterized by the same 1,5-diarylpyrrole scaffold and elucidated very interesting antitubercular/antimycobacterial properties. Some compounds identified are extremely promising and represent a step towards the design of novel lead structures in the fight against TB. Our efforts to this end are reviewed here.

Pulmonary mycobacterial disease: diagnostic performance of low-dose digital tomosynthesis as compared with chest radiography

PURPOSE

To compare the diagnostic performance of a low-radiation-dose digital tomosynthesis (DTS) technique with that of conventional radiography in the detection of lung lesions in patients with pulmonary mycobacterial disease.

MATERIALS AND METHODS

The institutional review board approved this study, and all patients provided informed consent. In this study, 100 patients (65 study patients, 35 control patients) underwent multidetector computed tomography (CT), chest radiography, and low-dose DTS (effective doses: 3.4, 0.02, and 0.05 mSv, respectively). Two radiologists evaluated radiographs and DTS images for the presence of parenchymal lesions and the number of cavities in each patient; CT served as the reference standard. Wilcoxon signed rank and McNemar tests and κ statistics were used.

RESULTS

The accuracies of DTS and radiography in depicting mycobacterial disease were 97% and 89%, respectively, for observer 1 (P = .039) and 99% and 93%, respectively, for observer 2 (P = .031). The accuracies of DTS and radiography in depicting each lesion type were, respectively, 95% and 77% for bronchiolitis, 92% and 76% for nodules, 86% and 79% for consolidation, and 93% and 70% for cavities. Interobserver agreement with DTS (κ = 0.62-0.94) was superior to that with radiography (κ = 0.46-0.62). Of a total of 141 cavities found with CT, means of 27 (19%) cavities at chest radiography and 108 (77%) cavities at DTS (P < .01) were detected by the two observers.

CONCLUSION

DTS performed with a low-dose technique is superior to radiography for the detection of lung lesions in patients with pulmonary mycobacterial disease.

Synthesis and pharmacological evaluation of clubbed isopropylthiazole derived triazolothiadiazoles, triazolothiadiazines and mannich bases as potential antimicrobial and antitubercular agents

A series of novel clubbed Isopropylthiazole derivatives triazolothiadiazines 2a-g, dihydro triazolothiadiazoles 3a-g, thioxotriazoles 4a-d, triazolothiadiazole 5, arylideneamino triazolethiones 7a-h and oxadiazolethiones 11a-b were synthesized and characterized by IR, (1)H NMR, (13)C NMR, elemental and mass spectral analysis. These compounds were evaluated for their preliminary in vitro antibacterial, antifungal and antitubercular activity against Mycobacterium tuberculosis H(37)Rv strain by broth dilution assay method. All the compounds exhibited moderate to significant antibacterial and antifungal activities. Results of the antitubercular screening against M. tuberculosis H(37)Rv showed compounds 7c and 7d exhibited good antitubercular activity (MIC 4 and 8 μg/mL) respectively, when compared with first line drug such as isoniazid (0.25 μg/mL).

Computer-assisted detection (CAD) methodology for early detection of response to pharmaceutical therapy in tuberculosis patients

The chest x-ray radiological features of tuberculosis patients are well documented, and the radiological features that change in response to successful pharmaceutical therapy can be followed with longitudinal studies over time. The patients can also be classified as either responsive or resistant to pharmaceutical therapy based on clinical improvement. We have retrospectively collected time series chest x-ray images of 200 patients diagnosed with tuberculosis receiving the standard pharmaceutical treatment. Computer algorithms can be created to utilize image texture features to assess the temporal changes in the chest x-rays of the tuberculosis patients. This methodology provides a framework for a computer-assisted detection (CAD) system that may provide physicians with the ability to detect poor treatment response earlier in pharmaceutical therapy. Early detection allows physicians to respond with more timely treatment alternatives and improved outcomes. Such a system has the potential to increase treatment efficacy for millions of patients each year.

Characterization of late tuberculosis infection in Sigmodon hispidus

We previously described primary tuberculosis in Sigmodon hispidus cotton rats up to 6 months following a pulmonary challenge. At that time, we observed fewer animals demonstrating disease as time from exposure progressed. We hypothesized that some cotton rats may control a primary infection to latency in a similar fashion to humans. The current experiment was designed to examine the natural progression of disease in S. hispidus at a later timepoint following a respiratory challenge with Mycobacterium tuberculosis (Mtb). An additional objective was to test whether cotton rats may become latently infected, and to determine whether latent disease might be activated by cyclophosphamide induced immune suppression. Thirty-four percent of the inoculated cotton rats died prior to 9 months following the challenge. However, 50% of immunocompetent animals surviving past 9 months demonstrated positive lung tissue cultures for Mtb without histologic evidence of disease. None of the immunosuppressed animals demonstrated this pattern. These findings are consistent with the development of latent tuberculosis infection in some cotton rats. Furthermore, it appears reactivation of disease occurs with cyclophosphamide induced immunosuppression. Cotton rats may serve as a model for latent as well as active tuberculosis infection.

[Tuberculosis in the Bajo Deba area (Guipúzcoa, Spain) from 1995 to 2006]

BACKGROUND

Within the Multicenter Project on Tuberculosis Research performed in Spain in 1996-1997, the Bajo Deba Area reported the highest incidence of tuberculosis in the Basque Country. We analyzed the clinical and epidemiological characteristics of the tuberculosis population diagnosed in our area during the period of 1995 to 2006.

METHODS

Ambispective, observational study.

RESULTS

A total of 584 patients were diagnosed with tuberculosis. The disease affected the respiratory tract in 509 cases and other sites in 75 cases. The mean annual incidence rate of tuberculosis was 64.5 cases per 100 000 inhabitants (91.6 in 1995-1998; 34.9 in 2003-2006). The mean annual incidence rate of smear-positive patients was 20.7 cases per 100 000 inhabitants (33.8 in 1995-1998; 12.9 in 2003-2006). The 15 to 24-year-old group was the most highly affected during the period of 1995 to 1998 (mean annual incidence rate 199.4 cases per 100 000); in contrast, the > 75-year-old group was the most highly affected during the period of 2003 to 2006 (121.1 cases per 100 000 inhabitants). Fifty-three patients were co-infected by HIV (9%) (yearly mean of 11.6% in 1995-1998 and 7% in 2003-2006). Löwenstein culture was positive in 431 cases (73.8%). Resistance to isoniazid was detected in 1.4% out of a total of 287 strains tested, and multidrug resistance was not observed. Nine patients were immigrants (1.5%). Treatment completion was greater in our area (505 patients, 86.4%), as compared to that recorded in the Guipuzcoa province during the same period (1956 of 2525 patients, 77.5%) (P < .01).

CONCLUSIONS

The Bajo Deba Area presented a high incidence of tuberculosis in the 1995 to 2006 period. Epidemiological trends showed a progressive decrease in the number of tuberculosis patients, with a shift from younger to older persons as the most highly affected age group. The impact of drug resistance and immigration was negligible on tuberculosis rates. The percentage of microbiologically confirmed cases was high. Treatment completion was satisfactory.

Pulmonary tuberculosis: up-to-date imaging and management

OBJECTIVE

Pulmonary tuberculosis (TB) is a common worldwide infection and a medical and social problem causing high mortality and morbidity, especially in developing countries. The traditional imaging concept of primary and reactivation TB has been recently challenged, and radiologic features depend on the level of host immunity rather than the elapsed time after the infection. We aimed to elaborate the new concept of the diagnosis and treatment of pulmonary TB, to review the characteristic imaging findings of various forms of pulmonary TB, and to assess the role of CT in the diagnosis and management of pulmonary TB.

CONCLUSION

Fast and more accurate TB testing such as bacterial DNA fingerprinting and whole-blood interferon-gamma assay has been developed. Miliary or disseminated primary pattern or atypical manifestations of pulmonary TB are common in patients with impaired immunity. CT plays an important role in the detection of TB in patients in whom the chest radiograph is normal or inconclusive, in the determination of disease activity, in the detection of complication, and in the management of TB by providing a roadmap for surgical treatment planning. PET scans using 18F-FDG or 11C-choline can sometimes help differentiate tuberculous granuloma from lung malignancy.

1,5-Diphenylpyrrole derivatives as antimycobacterial agents. Probing the influence on antimycobacterial activity of lipophilic substituents at the phenyl rings

Synthesis and biological evaluation of new derivatives of 1,5-bis(4-chlorophenyl)-2-methyl-3-(4-methylpiperazin-1-yl)methyl-1H-pyrrole (BM 212, 16) are reported. Variously substituted phenyl rings with different substitution pattern and lipophilicity were added to the pyrrole nucleus to evaluate their influence on the activity toward Mycobacterium tuberculosis (MTB) and atypical mycobacteria. The most active derivatives showed activity between 0.125-0.5 microg/mL (better than 16 and streptomycin) and protection index (64-256) higher than 16 (4) and similar to isoniazid and streptomycin (128).

Infection control in the dental office

The risk of infectious disease transmission is an inherent part of dental practice. Fortunately, such risks can be greatly reduced through modern infection control practices. Such practices include the use of various measures, including administrative, engineering, and work practice controls. Such measures should be codified in an office infection control plan, which should form the basis for the daily infection control activities of the staff. This article discusses some of the measures that should be taken to safeguard the health of dental healthcare workers and patients.

Scale-up of multidrug-resistant tuberculosis laboratory services, Peru

One-sentence summary for table of contents: Strategic design and implementation of these services is feasible in resource-poor settings.

Over the past 10 years, the Peruvian National Tuberculosis (TB) Program, the National Reference Laboratory (NRL), Socios en Salud, and US partners have worked to strengthen the national TB laboratory network to support treatment of multidrug-resistant TB. We review key lessons of this experience. The preparation phase involved establishing criteria for drug susceptibility testing (DST), selecting appropriate DST methods, projecting the quantity of DST and culture to ensure adequate supplies, creating biosafe laboratory facilities for DST, training laboratory personnel on methods, and validating DST methods at the NRL. Implementation involved training providers on DST indications, validating conventional and rapid first-line DST methods at district laboratories, and eliminating additional delays in specimen transport and result reporting. Monitoring included ongoing quality control and quality assurance procedures. Hurdles included logistics, coordinating with policy, competing interests, changing personnel, communications, and evaluation. Operational research guided laboratory scale-up and identified barriers to effective capacity building.

Insights into infectious disease in the era of Hippocrates

Hippocrates is traditionally considered the father of modern medicine, still influencing, 25 centuries after his time, various aspects of medical practice and ethics. His collected works include various references to infectious diseases that range from general observations on the nature of infection, hygiene, epidemiology, and the immune response, to detailed descriptions of syndromes such as tuberculous spondylitis, malaria, and tetanus. We sought to evaluate the extent to which this historical information has influenced the modern relevant literature. Associating disease to the disequilibrium of body fluids may seem an ancient and outdated notion nowadays, but many of the clinical descriptions presented in the Corpus Hippocraticum (Hippocratic Collection) are still the archetypes of the natural history of certain infectious diseases and their collective interplay with the environment, climate, and society. For this reason, modern clinicians and researchers continue to be attracted to these 'lessons' from the past - lessons that remain extremely valuable.

Mycobacterial bacilli are metabolically active during chronic tuberculosis in murine lungs: insights from genome-wide transcriptional profiling

Chronic tuberculosis represents a major health problem for one-third of the world's population today. A key question relevant to chronic tuberculosis is the physiological status of Mycobacterium tuberculosis during this important stage of infection. To examine the molecular bases of chronic tuberculosis and the role of host immunity in mycobacterial growth, we determined the mycobacterial transcriptional profiles during chronic and reactivation phases of murine tuberculosis using in vivo microarray analysis (IVMA). Following 28 days of aerosol infection, mycobacterial counts remained stable, although the bacilli were metabolically active with a 50% active transcriptome. The expression of genes involved in lipid and carbohydrate pathways was significantly enriched during the middle stage of chronic tuberculosis, suggesting a nutrient-rich microenvironment. A total of 137 genes were significantly regulated in mid-chronic tuberculosis (45 and 60 days) compared to an early stage (14 days) of infection. Additional sets of genes, including the virulence regulator virS, were up-regulated during the reactivation stage, indicating their possible roles in mycobacterial resurgence. Interestingly, a set of potential transcriptional regulators was significantly induced at the late stage of chronic tuberculosis. Bioinformatic analysis identified a large number of genes that could be regulated by one of the potential transcriptional regulators encoded by rv0348, including the sigF operon. Taken together, IVMA provided a better definition of the transcriptional machinery activated during chronic and reactivation stages of tuberculosis and identified a novel transcriptional regulator. A similar approach can be adopted to study key stages of intracellular pathogens.

The American cotton rat: A novel model for pulmonary tuberculosis

Several animal models are used to study Mycobacterium tuberculosis (MTB) infections, but none is a fully ideal model of human disease. The American cotton rat is an excellent model for the study of several human viral and bacterial respiratory infectious diseases, but until now has not been reported to be a model with MTB infection. Preliminary experiments were designed in which two species of cotton rats (Sigmodon hispidus and Sigmodon fulviventer) received respiratory challenges with M. tuberculosis via either intranasal or aerosol inoculation. Granulomatous disease, often with central necrosis, developed in the lungs, spleen, and lymph nodes of infected animals. The number of MTB bacilli in the lungs increased logarithmically until reaching a plateau in the second month after aerosol inoculation. There were differences in response to infection between the two species, with S. fulviventer demonstrating greater mortality than S. hispidus. Cytokine gene expression analysis by reverse transcriptase polymerase chain reaction (RT-PCR) was performed on both normal appearing and granulomatous lung tissue from infected animals. Many cytokine genes were more highly expressed in the focal areas of inflammation. Cotton rats provide another valuable tool in future research with tuberculosis.

Ethnopharmacological evaluation of the informant consensus model on anti-tuberculosis claims among the Manus

Ethnobotanists often utilize predictive models to analyze the potential of indigenously used medicinal plants. The most common of these prognostic models is the informant consensus model. This study evaluates use of this model through the analytical ethnopharmacology of Manus Province, Papua New Guinea (PNG). The informant consensus model enables researchers to prioritize plants for pharmacognostic evaluation, based on the relative frequency of plants cited in anthropological interviews. Fieldwork on Manus Island, PNG, led to the identification of 43 species of plants used in traditional medicine for persistent respiratory symptoms. Plants were collected, dried, micro-extracted using a new technique generated in our laboratory, and evaluated in vitro against Mycobacterium tuberculosis. The results, in the form of IC(50) values and modified selectivity indices (SI), were compared to the results of the anthropological models of informant consensus, and statistically compared through linear regression and t-tests. Results were not statistically significant (alpha=0.1), leading to the conclusions that the informant consensus assumptions were inaccurate in predicting anti-mycobacterial activity among the Manus for anti-TB claims.

The Phosphoenolpyruvate Carboxykinase of Mycobacterium Tuberculosis Induces Strong Cell-Mediated Immune Responses in Mice

Phosphoenolpyruvate carboxykinase (PEPCK) catalyzes guanosine or adenosine mononucleotide-dependent reversible conversion of oxaloacetate (OAA) and phosphoenolpyruvate (PEP). Mycobacterium (M) tuberculosis possesses a putative GTP-dependent PEPCK. To analyze the immune responses caused by PEPCK, the effects of PEPCK on the induction of CD4(+) T cells and cytokines such as IFN-gamma, IL-12 and TNF-alpha were evaluated in mice. It was found that the number of CD4(+) T cells was increased in the PEPCK immunized mice although the change of the number of CD8(+) T cells was not significant. The cytokines IFN-gamma, IL-12 and TNF-alpha were increased significantly in the mice immunized with PEPCK than those of incomplete adjuvant. These characteristics were further demonstrated in the mice infected by pckA mutated BCG strain. The results indicate that PEPCK can effectively induce cell-mediated immune response by increasing activity of cytokines and PEPCK may be a promising new subunit vaccine candidate for tuberculosis.

Pseudo-rationale design of efficient TB vaccines: Lesson from the mycobacterial 27-kDa lipoprotein

To develop or improve acellular vaccines against tuberculosis, scientists are in quest for the most efficient Th1 antigens. Immunization of mice with the M. tuberculosis 27-kDa antigen resulted in a strong Th1 immune response as indicated by serum analysis, splenocyte proliferation and cytokines secretion profile. Unexpectedly, mice immunized with 27-kDa turned out to be more susceptible to mycobacterial challenge as we found significant increase in the splenic cfu count compared to control groups. Moreover, the protection provided by BCG or other mycobacterial antigens was completely abolished once the 27-kDa antigen was added to the vaccine preparations. Further analysis of 27-kDa revealed that this lipoprotein is a B-cell mitogen, a feature that is known to be linked to enhanced virulence of the pathogen. However, by using the non-acylated form, 27DeltaSP, we excluded the involvement of the mitogenicity of 27-kDa in its deleterious effect. Currently, there is no explanation to the fact that the 27-kDa interferes with the protective immunity of other mycobacterial antigens; however, it is clear that 27-kDa need to be excluded from any future vaccine preparations. Indeed, we developed a multivalent vaccine that consists of six other mycobacterial antigens: 85B, 38-kDa, ESAT-6, CFP21, Mtb8.4 and 16-kDa. Immunization of mice with these antigens emulsified in Ribi adjuvant system and supplemented with recombinant IFN-gamma, resulted in strong Th1 immune response and a high protection level that was comparable to that of BCG.

Limited good and limited vision: multidrug-resistant tuberculosis and global health policy

Almost a third of the world's population is infected with Mycobacterium tuberculosis, the organism that causes tuberculosis disease. Most of those infected never fall ill, but individuals who do can recover if they have access to effective therapies. This paper discusses certain ethical and ethnographic issues raised by cases in which patients are infected with M. tuberculosis strains resistant to at least the two most powerful drugs on which therapy is usually based. In most poor countries, people with such multidrug-resistant tuberculosis (MDR-TB) were, until very recently, considered "untreatable." In addition to being consigned to a permanent state of ill health, they were also at risk of transmitting their resistant strain to others. In this paper we discuss the logic of "cost-effectiveness," which international health policy-makers utilized to make the case that treatment of MDR-TB is not feasible in resource poor settings. These analyses, which have held sway in public health policy for many years, are flawed, we argue, because they ignore and conceal the social determinants of access to health services and often rely on assumptions rather than evidence. We propose that policies based solely on analyses of cost-effectiveness of specific interventions for individual settings can be short-sighted and, because they do not pay sufficient attention to the social, political, economic, epidemiological and pathophysiological factors influencing the production of health, will ultimately hinder progress toward effective global TB control.

Tuberculosis in stem cell transplant patients

Tuberculosis (TB) is an increasing health problem, and patients undergoing stem cell transplantation (SCT) are at high risk of acquiring TB. Following a review of the medical literature, this article reports the current situation of TB in SCT patients. A PubMed search was undertaken using the keywords 'tuberculosis', 'stem cell transplantation' and 'bone marrow transplantation', and cases with meaningful data for analysis were included. The medical literature contains relatively few data on TB and SCT. Although there is a risk of TB in allogeneic SCT patients, this is less than in solid organ transplant patients, and the risk in autologous SCT patients is similar to the risk in the general population. The incidence of TB in SCT patients is proportional to the incidence of TB in the general population. Evidence favouring TB prophylaxis is not well established. While allogeneic transplantation carries a risk of TB, this is not true for autologous transplantation. Prophylaxis can only be an option for selected patients or countries with high rates of TB.

Virulent clinical isolates ofMycobacterium tuberculosisgrow rapidly and induce cellular necrosis but minimal apoptosis in murine macrophages

In this study, we investigated the ability of four clinical isolates of Mycobacterium tuberculosis representing a range of virulence for their capacity to grow in bone marrow-derived macrophages. The rate of growth of each of the isolates in macrophages reflected their known virulence, but the most virulent isolates strongly induced production of the cytokine tumor necrosis factor alpha. A key difference, however, was the degree of cell cytotoxicity observed with the more virulent strains after several days in culture. Staining of cell monolayers for DNA fragmentation indicative of apoptosis showed that this was minimal and only evident to any degree in macrophages infected with the most virulent strains. In contrast, electron microscopy revealed damage of macrophages consistent with cell necrosis. These results suggest that rapid intracellular growth rate and induction of necrotic cell death within host macrophages are virulence factors of M. tuberculosis in the early stages of bacterial infection. They further imply that infected cell apoptosis, regarded as a defense mechanism or cross-priming mechanism, plays a minimal role.

Animal models of tuberculosis

It was Robert Koch who recognized the spectrum of pathology of tuberculosis (TB) in different animal species. The examination of clinical specimens from infected humans and animals confirmed the variable patterns of pathological reactions in different species. Guinea pigs are innately susceptible while humans, mice and rabbits show different level of resistance depending upon their genotype. The studies of TB in laboratory animals such as mice, rabbits and guinea pigs have significantly increased our understanding of the aetiology, virulence and pathogenesis of the disease. The introduction of less than five virulent organisms into guinea pigs by the respiratory route can produce lung lesions, bacteraemia and fatal diseases, which helped the extrapolation of results of such experiments to humans. The similarities in the course of clinical infection between guinea pigs and humans allow us to model different forms of TB and to evaluate the protective efficacy of candidate vaccines in such systems. The only limitation of this model, however, is a dearth of immunological reagents that are required for the qualitative and quantitative evaluation of the immune responses, with special reference to cytokines and cell phenotypes. Another limitation is the higher cost of guinea pigs compared with mice. The rabbit is relatively resistant to Mycobacterium tuberculosis, however following infection with virulent Mycobacterium bovis, the rabbit produces pulmonary cavities like humans. The rabbit model, however, is also limited by the lack of the immunological reagents. Mice are the animal of choice for studying the immunology of mycobacterial infections and have contributed much to our current understanding of the roles of various immunological mechanisms of resistance. The resistance of mice to the development of classic TB disease, however, represents a significant disadvantage of the mouse model. Although non-human primates are closely related to humans, owing to high cost and handing difficulties they have not been exploited to a large extent. As all existing animal models fail to mimic the human disease perfectly, efforts should be focused on the development of the non-human primate(s) as the alternative animal model for TB.

Peritoneal Tuberculosis in a 15-Month-Old Male: Surgical Diagnosis of an Insidious Disease

BACKGROUND

Peritoneal involvement is a relatively rare complication of tuberculosis, accounting for approximately 3.3% of extrapulmonary disease in the United States. Clinical diagnosis relies on a preponderance of indirect evidence and is often delayed. We describe such a patient.

METHODS

An otherwise healthy 15-month-old male presented with fever, abdominal distention, vague abdominal pains, and a few episodes of watery diarrhea. Standard laboratory and radiologic work-up was unrevealing, and after a prolonged hospitalization, caseating granulomas were identified at diagnostic laparotomy.

RESULTS

Definitive treatment was further delayed pending culture results, and the patient's condition worsened until fulminant cardiovascular collapse led to his demise.

CONCLUSIONS

Despite effective chemotherapeutic regimens, the overall mortality of tuberculous peritonitis may be as high as 51%. The diagnosis must be considered and empiric antituberculous treatment started early in the course of the disease, even if definitive diagnosis is still pending.

Validation of the use of Middlebrook 7H10 agar, BACTEC MGIT 960, and BACTEC 460 12B media for testing the susceptibility of Mycobacterium tuberculosis to levofloxacin

Levofloxacin, the active l-isomer of the quinolone ofloxacin, is now widely accepted for treatment of multidrug-resistant tuberculosis. Because the drug is now widely used, we sought to establish susceptibility test conditions for Mycobacterium tuberculosis against levofloxacin by the traditional reference method, agar proportion (AP), the commonly used BACTEC 460 radiometric system, and the newer BACTEC MGIT 960 method. To determine the stability of levofloxacin in the two newer test systems (BACTEC 460 and BACTEC MGIT 960), media containing subinhibitory levels of levofloxacin were prepared and stored at 4 and 37 degrees C for 14 days. The stored media were inoculated with H37Rv, and the drug activity was compared to freshly prepared media. Results show that levofloxacin is stable over the course of testing. Next, optimum levofloxacin test concentrations were determined for AP, BACTEC 460, and BACTEC MGIT 960 methods. MICs were determined for 32 pan-susceptible isolates of M. tuberculosis obtained from presumably untreated patients and 14 quinolone-resistant isolates. The levofloxacin-resistant strains either were isolated from patients who remained culture-positive despite treatment with a quinolone agent (six strains) or contained known mutations in gyrA (eight strains). Levofloxacin MICs resulted in a bimodal pattern with values for resistant strains consistently higher than those for pan-susceptible strains. Results show that levofloxacin concentrations of 2 microg/ml (BACTEC 460 and BACTEC MGIT 960) and 1 microg/ml (AP) inhibited the growth of all pan-susceptible strains while permitting the growth of all levofloxacin-resistant strains. Confirmatory tests with a subset of pan-susceptible and levofloxacin-resistant isolates validated the selected test concentrations.