Time to detection of Mycobacterium tuberculosis using the MGIT 320 system correlates with colony counting in preclinical testing of new vaccines.

Clinical studies have suggested that the enumeration of mycobacteria by using automated liquid systems is a faster and simpler alternative to quantitative cultures. Here, we show that the time to detection of M. tuberculosis growth as measured with the MGIT 320 liquid culture system inversely correlates with CFU determinations from culture on solid media and that mycobacterial quantification using the MGIT system is faster and easier to perform than CFU plating.

Novel conjugate of moxifloxacin and carboxymethylated glucan with enhanced activity against Mycobacterium tuberculosis.

Mycobacterium tuberculosis is an intracellular pathogen that persists within macrophages of the human host. One approach to improving the treatment of tuberculosis (TB) is the targeted delivery of antibiotics to macrophages using ligands to macrophage receptors. The moxifloxacin-conjugated dansylated carboxymethylglucan (M-DCMG) conjugate was prepared by chemically linking dansylcadaverine (D) and moxifloxacin (M) to carboxymethylglucan (CMG), a known ligand of macrophage scavenger receptors. The targeted delivery to macrophages and the antituberculosis activity of the conjugate M-DCMG were studied in vitro and in vivo. Using fluorescence microscopy, fluorimetry, and the J774 macrophage cell line, M-DCMG was shown to accumulate in macrophages through scavenger receptors in a dose-dependent (1 to 50 microg/ml) manner. After intravenous administration of M-DCMG into C57BL/6 mice, the fluorescent conjugate was concentrated in the macrophages of the lungs and spleen. Analyses of the pharmacokinetics of the conjugate demonstrated that M-DCMG was more rapidly accumulated and more persistent in tissues than free moxifloxacin. Importantly, therapeutic studies of mycobacterial growth in C57BL/6 mice showed that the M-DCMG conjugate was significantly more potent than free moxifloxacin.

Deformin, a substance found in Bartonella bacilliformis culture supernatants, is a small, hydrophobic molecule with an affinity for albumin.

Culture supernatants of Bartonella bacilliformis were previously shown to contain a factor, called deforming factor or deformin, which causes deformation and invagination of red cell membranes and formation of intracellular vacuoles. This factor is here shown to be a small water-soluble molecule, approximately 1400 Da as estimated by gel-filtration chromatography. Deforming factor binds tightly to albumin, especially albumin dimers and multimers, present in the growth medium. It can be released from albumin with 50% ethanol and has been partially purified by filtration and HPLC.

Induction of macrophage binding to virally infected cells by low levels of lipopolysaccharide.

Bone marrow culture-derived macrophages (BMCM) and vesicular stomatitis virus-infected BALB/c-3T3 cells (3T3-VSV) were used to determine whether macrophages could be activated to bind virally infected cells. Although lipopolysaccharide (LPS)-activated BMCM bound some uninfected BALB/c-3T3 cells, the number of targets that were bound increased with increasing times between infection and assay. Furthermore, LPS-activated BMCM bound more 3T3-VSV cells than did control macrophages. As more targets were added, the number of targets bound by the unactivated macrophages remained relatively level. However, the number of targets bound by the activated macrophages increased with increasing concentrations of added targets until they reached a plateau that was eight times greater than that bound by the unactivated BMCM. When BMCM were exposed to LPS for 24 h before assay, they lost both their ability to bind to 3T3-VSV and their cytolytic activity against those targets. However, as when using P815, a standard tumor target, the acquisition of binding of 3T3-VSV could be separated from macrophage cytolytic activity against those targets. The amount of LPS required to activated BMCM for increased binding of 3T3-VSV cells was 10-100 times lower than that needed to induce cytolytic activity for 3T3-VSV cells. Each of these values was approximately 100-fold lower than the amount of LPS required to induce the corresponding activity (binding or cytotoxicity) by using P815 targets.