Tuberculosis Clinical Strains Research Articles

Rapid film-based determination of antibiotic susceptibilities of Mycobacterium tuberculosis strains by using a luciferase reporter phage and the Bronx Box.

Detecting antibiotic resistance in Mycobacterium tuberculosis is becoming increasingly important with the global recognition of drug-resistant strains and their adverse impact on clinical outcomes. Current methods of susceptibility testing are either time-consuming or costly; rapid, reliable, simple, and inexpensive methods would be highly desirable, especially in the developing world where most tuberculosis is found. The luciferase reporter phage is a unique reagent well-suited for this purpose: upon infection with viable mycobacteria, it produces quantifiable light which is not observed in mycobacterial cells treated with active antimicrobials. In this report, we describe a modification of our original assay, which allows detection of the emitted light with a Polaroid film box designated the Bronx Box. The technique has been applied to 25 M. tuberculosis reference and clinical strains, and criteria are presented which allow rapid and simple discrimination among strains susceptible or resistant to isoniazid and rifampin, the major antituberculosis agents.

Glycinergic and GABAergic neurons in the ventral nucleus of the lateral lemniscus in mammals

Mycobacterium tuberculosis is naturally resistant to clarithromycin (CLR). The genes Rv3197A (whiB7) and Rv1988 (ermMT) have been shown to be involved in the resistant phenotype. In this study, a CLR-susceptible M. tuberculosis clinical strain was identified, designated as DS3214, and the nucleotide sequences and expression profiles of whiB7 and ermMT were investigated. The results revealed that strain DS3214 contained a one nucleotide deletion in whiB7, leading to a truncated peptide. Expression of whiB7 was low, whereas comparable expression of ermMT was determined compared with the reference strain M. tuberculosis H37Rv. Overexpression of the mutant whiB7 in M. tuberculosis H37Ra did not increase the minimum inhibitory concentration (MIC) to CLR or kanamycin, indicating the defect of the mutant WhiB7. The CLR-susceptible M. tuberculosis clinical strain, whose whiB7 is naturally mutated, was first described in this study and whiB7 has been shown to play a role in the CLR-susceptible phenotype.

Fermentative preparation of S35-siomycin, a sulfur-containing peptide antibiotic.

Siomycin is a sulfur-containing peptide antibiotic which resembles thiostrepton in structure2) and is produced by Streptomyces sioyaensis1). The antibiotic shows high activity against various gram-positive bacteria including Mycobacterium tuberculosis and many clinical resistant strains of Staphylococcus. YAGI et al.3) recently reported that the yield of siomycin is increased three- to four-fold by the addition of elemental sulfur to the fermentation broth where the sulfur is oxidized to thiosulfate, and also that the incorporation of thiosulfate ions is one of the key steps in siomycin biosynthesis. This work has been carried out in order to prepare S35-siomycin for pharmacological use, and owes much to the above work of YAGI et al.3)