OBJECTIVETo investigate the distribution of the Beijing genotypes of Mycobacterium tuberculosis (M. tuberculosis) and the relationships between Beijing genotype strains and drug-resistant phenotypes in China.

METHODSClinical isolates were collected during a 9-month research period from April to December in 2008 in six geographic regions of China. One isolate that had been biochemically confirmed to be a member of the M. tuberculosis complex was collected from each patient. The demographic data of the patients (eg. sex, age, and history of tuberculosis) as well as the drug resistance patterns and sources of the clinical isolates were collected. Drug susceptibility testing was performed using proportion method. Beijing genotypes of M. tuberculosis were identified by spacer oligonucleotide typing or insertion of IS6110 in the genomic dnaA-dnaN locus.

RESULTSAmong the 410 M. tuberculosis clinical isolates, 67.1% (275/410) isolates were Beijing genotypes of M. tuberculosis. Significantly larger proportions of tuberculosis patients were infected with Beijing genotypes in the northeastern regions of China than that of in the central-western regions (chi2 = 20.50, P = 0.000). No significant associations were found either between Beijing genotype strains and patients' age, sex, or treatment history. Multidrug-resistant isolates and rifampin-resistant isolates were more common among Beijing genotype strains than among non-Beijing strains (P = 0.002, P = 0.005).

CONCLUSIONSAbout two third of the clinical isolates of M. tuberculosis in China are Beijing genotypes. Beijing genotype strains are not correlated with patients' age, sex, treatment history. People living in the northeastern regions of China are more susceptible to Beijing genotypes than those living in the central-western of China. Beijing genotype strains tend to be rifampin-resistant or multidrug-resistant.

Antitubercular Agents ; pharmacology ; China ; Genotype ; Humans ; Mycobacterium tuberculosis ; classification ; genetics ; Phenotype ; Rifampin ; pharmacology ; Tuberculosis ; drug therapy ; Tuberculosis, Multidrug-Resistant ; genetics

Tuberculosis (TB) is an ancient infectious disease. Before the availability of effective drug therapy, it had high morbidity and mortality. In the past 100 years, the discovery of revolutionary anti-TB drugs such as streptomycin, isoniazid, pyrazinamide, ethambutol and rifampicin, along with drug combination treatment, has greatly improved TB control globally. As anti-TB drugs were widely used, multidrug-resistant (MDR) and extensively drug-resistant (XDR) strains of Mycobacterium tuberculosis emerged due to acquired genetic mutations, and this now presents a major problem for effective treatment. Genes associated with drug resistance have been identified, including katG mutations in isoniazid resistance, rpoB mutations in rifampin resistance, pncA mutations in pyrazinamide resistance, and gyrA mutations in quinolone resistance. The major mechanisms of drug resistance include loss of enzyme activity in prodrug activation, drug target alteration, overexpression of drug target, and overexpression of the efflux pump. During the disease process, Mycobacterium tuberculosis may reside in different microenvironments where it is expose to acidic pH, low oxygen, reactive oxygen species and anti-TB drugs, which can facilitate the development of non-replicating persisters and promote bacterial survival. The mechanisms of persister formation may include toxin-antitoxin (TA) modules, DNA protection and repair, protein degradation such as trans-translation, efflux, and altered metabolism. In recent years, the use of new anti-TB drugs, repurposed drugs, and their drug combinations has greatly improved treatment outcomes in patients with both drug-susceptible TB and MDR/XDR-TB. The importance of developing more effective drugs targeting persisters of Mycobacterium tuberculosis is emphasized. In addition, host-directed therapeutics using both conventional drugs and herbal medicines for more effective TB treatment should also be explored. In this article, we review historical aspects of the research on anti-TB drugs and discuss the current understanding and treatments of drug resistant and persistent tuberculosis to inform future therapeutic development.
Humans ; Pyrazinamide/therapeutic use* ; Isoniazid/therapeutic use* ; Antitubercular Agents/therapeutic use* ; Tuberculosis, Multidrug-Resistant/microbiology* ; Mycobacterium tuberculosis/genetics* ; Tuberculosis/drug therapy* ; Rifampin/therapeutic use* ; Mutation ; Drug Resistance, Multiple, Bacterial/genetics*

Identification and validation of a new target is one of the most important steps for new antituberculosis (TB) drug discovery. Researches have shown that Mycobacterium tuberculosis (Mtb) encodes 20 CYP450 enzymes which play important roles in the synthesis and metabolism of lipid, cholesterol utilization, and the electron transport of respiratory chain in Mtb. With the critical roles within the organism as well as the protein structures of six Mtb CYP450 enzymes being clarified, some of them have been highlighted as potential anti-tuberculosis targets. In this paper, the phylogenetic analysis, the structural features, and the enzymatic functions of Mtb CYPs, as well as the mechanism of interactions with selective inhibitors such as azole antifungal agents for the CYPs have been reviewed and summarized. The druggability of the CYPs has also been analyzed for their further utility as targets in high throughput screening and rational design of more selective inhibitors.
Antitubercular Agents ; chemistry ; pharmacology ; Azoles ; chemistry ; pharmacology ; Cytochrome P-450 Enzyme Inhibitors ; chemistry ; pharmacology ; Cytochrome P-450 Enzyme System ; genetics ; metabolism ; Drug Delivery Systems ; methods ; Drug Discovery ; Humans ; Mycobacterium tuberculosis ; drug effects ; enzymology ; genetics ; Phylogeny ; Tuberculosis ; drug therapy ; microbiology

Mycobacterium tuberculosis, which belongs to the genus Mycobacterium, is the pathogenic agent for most tuberculosis (TB). As TB remains one of the most rampant infectious diseases, causing morbidity and death with emergence of multi-drug-resistant and extensively-drug-resistant forms, it is urgent to identify new drugs with novel targets to ensure future therapeutic success. In this regards, the structural genomics of M. tuberculosis provides important information to identify potential targets, perform biochemical assays, determine crystal structures in complex with potential inhibitor(s), reveal the key sites/residues for biological activity, and thus validate drug targets and discover novel drugs. In this review, we will discuss the recent progress on novel targets for structure-based anti-M. tuberculosis drug discovery.
Bacterial Proteins ; antagonists & inhibitors ; chemistry ; genetics ; metabolism ; Crystallography, X-Ray ; Drug Discovery ; Genomics ; Models, Molecular ; Molecular Targeted Therapy ; Mycobacterium tuberculosis ; drug effects ; genetics ; metabolism ; Protein Conformation

Last two decades have witnessed the resurging of tuberculosis (TB) and multi-drug resistant TB, even the extensive drug resistant TB. It is urgent to develop novel drug to combat the increasingly worsen TB. Capreomycin is an ideal second-line TB drug. It is also recognized as an attractive template to develop more peptide antibiotics. In this review, the biosynthesis gene cluster of capreomycin, the action mechanism unveiled by transcriptome and novel resistance rational are summarized from the recent functional genomic investigation.
Antibiotics, Antitubercular ; chemistry ; pharmacology ; Capreomycin ; chemistry ; pharmacology ; Drug Resistance, Multiple, Bacterial ; drug effects ; Genes, Bacterial ; Mycobacterium tuberculosis ; drug effects ; genetics ; Open Reading Frames ; Ribosomal Proteins ; metabolism ; Tuberculosis, Multidrug-Resistant ; drug therapy

Antitubercular Agents ; pharmacology ; therapeutic use ; Diagnostic Techniques, Respiratory System ; Drug Approval ; Drug Resistance ; Female ; Gene Amplification ; Humans ; Immune Adherence Reaction ; Male ; Treatment Failure ; Tuberculosis ; diagnosis ; drug therapy ; genetics

Although tuberculosis is largely a curable disease, it remains a major cause of morbidity and mortality worldwide. Although the standard 6-month treatment regimen is highly effective for drug-susceptible tuberculosis, the use of multiple drugs over long periods of time can cause frequent adverse drug reactions. In addition, some patients with drug-susceptible tuberculosis do not respond adequately to treatment and develop treatment failure and drug resistance. Response to tuberculosis treatment could be affected by multiple factors associated with the host-pathogen interaction including genetic factors and the nutritional status of the host. These factors should be considered for effective tuberculosis control. Therefore, therapeutic drug monitoring (TDM), which is individualized drug dosing guided by serum drug concentrations during treatment, and pharmacogenetics-based personalized dosing guidelines of anti-tuberculosis drugs could reduce the incidence of adverse drug reactions and increase the likelihood of successful treatment outcomes. Moreover, assessment and management of comorbid conditions including nutritional status could improve anti-tuberculosis treatment response.
Antitubercular Agents/blood/*therapeutic use ; Arylamine N-Acetyltransferase/genetics ; Chromatography, High Pressure Liquid ; Drug Monitoring ; Humans ; Nutritional Status ; Pharmacogenetics ; Tandem Mass Spectrometry ; Tuberculosis/*drug therapy

Investigations on the genetic diversity of Mycobacterium tuberculosis in China have shown that Beijing genotype strains play a dominant role. To study the association between the M. tuberculosis Beijing genotype and the drug-resistance phenotype, 1286 M. tuberculosis clinical isolates together with epidemiological and clinical information of patients were collected from the center for tuberculosis (TB) prevention and control or TB hospitals in Beijing municipality and nine provinces or autonomous regions in China. Drug resistance testing was conducted on all the isolates to the four first-line anti-TB drugs (isoniazid, rifampicin, streptomycin, and ethambutol). A total of 585 strains were found to be resistant to at least one of the four anti-TB drugs. The Beijing family strains consisted of 499 (53.20%) drug-sensitive strains and 439 (46.80%) drug-resistant strains, whereas the non-Beijing family strains comprised 202 (58.05%) drug-sensitive strains and 146 (41.95%) drug-resistant strains. No significant difference was observed in prevalence (χ= 2.41, P > 0.05) between the drug-resistant and drugsensitive strains among the Beijing family strains. Analysis of monoresistance, multidrug-resistant TB, and geographic distribution of drug resistance did not find any relationships between the M. tuberculosis Beijing genotype and drug-resistance phenotype in China. Results confirmed that the Beijing genotype, the predominant M. tuberculosis genotype in China, was not associated with drug resistance.
Antitubercular Agents ; therapeutic use ; China ; epidemiology ; Drug Resistance, Multiple, Bacterial ; Genetic Variation ; Genotype ; Humans ; Microbial Sensitivity Tests ; Mycobacterium tuberculosis ; genetics ; isolation & purification ; Phenotype ; Tuberculosis, Multidrug-Resistant ; drug therapy ; epidemiology

Abscess ; diagnosis ; etiology ; therapy ; Antitubercular Agents ; therapeutic use ; DNA, Bacterial ; analysis ; Debridement ; methods ; Diagnosis, Differential ; Follow-Up Studies ; Humans ; Male ; Metacarpus ; Middle Aged ; Mycobacterium tuberculosis ; genetics ; isolation & purification ; Tuberculosis, Pulmonary ; complications ; drug therapy ; microbiology

Gallbladder tuberculosis is an extremely rare disease that is rarely reported in the literature. Arriving at the correct diagnosis of gallbladder tuberculosis is difficult, and it is usually made by histopathologic examination after cholecystectomy. However, due to the low sensitivity of acid-fast stain and culture result, diagnosing gallbladder tuberculosis is still demanding even after tissue acquisition. To overcome this problem, tuberculosis-polymerase chain reaction (TB-PCR) is performed on the resected specimen, which has high sensitivity and specificity. A 70-year-old female who had previously undergone total gastrectomy for advanced gastric cancer was admitted with right upper quadrant pain. Abdominal ultrasonography and computed tomography revealed acute cholecystitis without gallstones or sludge. She underwent cholecystectomy and the histopathologic finding of the specimen showed chronic active cholecystitis without gallstones or sludge. Because she was suspected to have pulmonary tuberculosis, TB-PCR was also performed on the resected gallbladder. TB-PCR showed positive reaction for Mycobacterium tuberculosis and we could diagnose it as gallbladder tuberculosis. Herein, we present a case of gallbladder tuberculosis diagnosed by TB-PCR from resected gallbladder.
Aged ; Antitubercular Agents/therapeutic use ; Cholecystitis, Acute/*diagnosis/surgery/ultrasonography ; DNA, Bacterial/analysis ; Female ; Humans ; Mycobacterium tuberculosis/genetics/isolation & purification ; Polymerase Chain Reaction ; Tomography, X-Ray Computed ; Tuberculosis/*diagnosis/drug therapy/microbiology